Due To The Many Variables In The Field CSW Coatings Strictly Cannot And Do Not Discuss Any Form Of Troubleshooting Without Required Necessary Information Requested In Our Escalated Case Inquiry Form.
This Includes Both Written And Verbal Correspondence.
Level 1 Support
Troubleshooting Guide – Typical troubleshooting experienced by the bulk of applications designed as both an educational tool and self managed problem solver to minimize downtime and enable 24x7 availability.
Level 2 Support
Escalated Case Inquiry Form – Form submission to Technical with written assisted responses referencing and elaborating on Troubleshooting Guide. Allow up to 3 business days for replies.
Level 3 Support
Phone Support – Outbound call to customer at Technical discretion once Level 1 and Level 2 support has been thoroughly exhausted. Allow up to 3 business days once escalated.
Level 4 Support
Third Party Site Visit
$250 per hour plus expenses. (GST inclusive)
Minimum 2 hour purchase.
Site visit fees refunded in full if manufactured products are proven to be defective.
Full technical report of issue, causes and rectification.
Substrate and coating tests, surrounding landscape investigations
Evaluation of quality assurance reports filled in accordance with AS 3894
Testing of coating and substrate in accordance with AS 3894 and AS 1580
Testing and QC trial of manufactured product, including attempted replication of problems
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CSW Coatings understands that should an application project not turn out as expected,
the first port of call is to question the product???
- Product batches are generally manufactured in 10,000 litre batches.
- Single drum(s) failure from 10,000 litre batch would be extremely rare.
- Sealers/coatings perform in a consistent and predictable manner with a very small percentage of applications developing issues. These issues most likely can be attributed to improper surface preparation, moisture issues or application methods.
There Is Always A Trigger Mechanism For Sealer / Coating Issues!!
Read the application instructions, then apply to an uninstalled, virgin tile / stone.
Note the differences between this test and your applied surface. Common sense will usually show that something occurred on the surface that caused the problem.
See other areas of this Problem Solving section now that you have more information about the situation.
Video: AS/NZS 2311:2009 Australian Standards:
Surface Preparation and Applicators Obligations.
Video Credits: The National Institute of Painting and Decorating
AS/NZS 2311:2009 Section 3.1 Par 2: “Surface assessment and preparation are particularly important as the painter may be held liable for any future failure because the very act of painting a surface may be interpreted as accepting that surface as being suitable for painting”.
Painters/applicators need to follow the testing and application/direction requirements recommended in AS/NZS 2311:2009, Product Label and Website. Failure to take the precautions indicated in both AS/NZS 2311:2009 and manufacturer’s information and recommendations, exposes the painter/applicator to a risk of premature failure.
Level 1 Support: Troubleshooting Guide.
Question: I used a sealer and certain areas of the floor remain white and hazy. Why did this happen, and how do I fix it?
Answer: When dealing with sealer-related problems, the trigger mechanism often revolves around one or more of the following factors: moisture, temperature, surface contamination, and application method. In this case, the long, thin streaks of white indicate over-application of the sealer with a roller. If the roller is overloaded with sealer, it tends to drag large amounts across the surface in streaks and ribbons. These thicker streaks of sealer skin over on the top surface, preventing the sealer from fully curing. Instead of turning clear, the sealer remains white and milky in appearance. Another factor at play is the surface texture of the overlay. If the surface has differences in elevation, sealer tends to puddle in the valleys. It will also collect in cracks and joints. These areas are more susceptible to this white hazing or milkiness.
Fixing this situation can be as easy as applying a thin solvent bath or as involved as stripping the entire area, depending on the sealer product used. A simple solvent (xylene, acetone, or methyl ethyl ketone) wiped over the surface can loosen the sealer, allowing the underlying material to cure and turn clear. If this method doesn't work, or destroys the sealer, you'll need to use a chemical stripper to remove the affected areas. (Be sure to test the stripper on a small section first to determine the effect.) Once the entire area is stripped and cleaned, reapply the sealer, taking care not to overload the roller.
Question: What is causing grey spots on my surface
Answer: Sealer diffusion. This phenomenon, where the sealer is no longer adhered to the concrete, looks a lot like efflorescence from a distance, but on closer inspection is actually more gray or cloudy. Without getting into complex physics, the sealer has lifted (even if only by micro-meters) and it causes the discoloration. The small air gap that now exists between the sealer and concrete causes the light to diffuse and create the grayish-white cloudy look. Moisture-vapor pressure, contamination or over-application of the sealer can cause this problem.
Another thing it may be is moisture condensation trapped under the sealer. Have you had any major wet weather events in the weeks prior to this occurring? As with most decorative concrete issues, it could be a combination of both of these things, with a little efflorescence thrown in for good measure.
To fix the problem, wait until you get some warmer weather. A xylene bath (lightly soaking the problem area with a xylene solvent and back rolling) is the first step. If this does not work, you will probably need to strip off some or all of the sealer.
Question: There are spots concentrated around the edges of the slab
Answer: The acrylic sealer is actually fracturing. Typically this occurs when the sealer is applied too heavily. Acrylic sealers are designed to go down very thin. Even with two coats, the thickness should be only about 1 mm. To give you some reference, a credit card is about 1mm thick.
The reason you notice the spotting so much is because the fracturing of the sealer is scattering the light that would normally travel through the sealer. When light can travel through a sealer without interference, you'll see a nice, clean reflection. Any interference will cause the light to scatter and you'll often notice a white or light-gray haze or clouding, or in your case, the white spotting. At higher solids, you need to be very careful to apply the sealer thinly. Acrylics are tough stuff, but they are prone to cracking once they exceed 1 to 2 mils in thickness. If you like the high-gloss look of an acrylic but want to avoid this problem in the future, consider using a two-part urethane, which is designed to go down at 3mm. Or spread out the acrylic more thinly to achieve a 1mm thickness.
Question: While applying the sealer on the first half of the floor, I could see roller marks and bubbles and the primer started to string up on me. I mixed a new batch and proceeded to finish rolling the rest of the floor but at a much faster pace, and I seemed to have no problem. But now roller marks are visible throughout the entire floor, not to mention the bubbles.
Answer: Sanding will take surface bubbles out, but buffing with a floor machine will not be aggressive enough. If the bubbles go deeper than the surface, you may need to strip and start over. My suggestion is to try sanding out the marks and then reapply your topcoat. If this does not work, strip down to a point were no roller marks or bubbles appear and start over. Do a test area before doing the entire floor.
All rollers produce lines, with more material coming off the ends of the roller as it moves across the surface. Depending on the material used, application temperature and pot life, the roller lines may or may not even out. The speed of rolling, the amount of material on the roller and the weight pushing down on the roller also play a role in leaving roller marks. Picture a car tyre that has mud on it. If you drive slowly, the mud comes off the tyre evenly. If you speed up, the mud flies all over and leaves more prominent marks on the outside edges of the tyre.
Question: My penetrating sealer no longer beads water and seems porous.
Answer: Penetrating sealers are breathable sealers and are specifically designed to allow water vapour transmission. The initial obvious beading may have been excess residue (presented sometimes as a sheen) which in time has been reduced. Although the “bead” may go away anywhere from 2-12 months, the sealer will continue to work within the pores. For further explanation please see website on "How Does A Penetrating Sealer Work?". Eventually, dependent on environmental variables a sealer will require a maintenance coat(s).
Question: I applied sealer with a roller and ended up with lap lines. How do I prevent these lines, and is there a way to remove them?
Answer: First, be sure you are using the proper applicator for the sealer type. Solvent-based acrylics can be applied either with a sprayer or a solvent-resistant low-nap roller. Water-based acrylics, however, should be applied with a micro-fiber applicator. And heavy-bodied coatings (such as urethanes and epoxies) should be applied squeegee or specialty roller followed by a spiked roller for de-gassing.
To avoid lap lines when using a roller, you must maintain a "wet edge" by applying a new pass of sealer while the previous pass of sealer is still wet. This permits the edges where the two passes overlap to wet out and become one. Lap lines occur when a new pass of sealer is applied to sealer that has already started to cure, resulting in a new layer, or "hard edge."
Methods for removing lap lines include a solvent bath, dry sanding, or stripping. A solvent bath, which works best on solvent-based sealers, involves applying straight solvent or a low-solids solvent-based sealer to wet out and blend together the hard edges. Typically the solvent re-liquefies the previous layer of sealer and no additional working of the coating is needed. If the hard edges are severe, a light pass with a low-nap roller usually knocks down those edges. Dry sanding is often used on water-based sealers. Use a 200+ grit screen to lightly sand the surface and knock down the lap lines, and then re-apply the same water-based sealer to even out the sanded surface. If the lap lines are severe, you may need to strip the sealer completely and start over.
Question: I recently applied two coats of an acrylic sealer to a stained floor. After the sealer dried, the floor appeared blotchy, with some areas glossy and others not. What causes this, and should I apply more sealer to remedy the situation?
Answer: If you were to look at a concrete floor under a microscope, you would see what looks like an endless range of plateaus and valleys. The number and depth of these plateaus and valleys is directly proportional to the finish of the concrete. A smooth finish has fewer of them while a rough finish looks like the Grand Canyon. When sealer is applied, it fills the valleys, but you may need to apply more than one coat depending on the finish of the floor. Typically when we see a floor that has blotchy areas of gloss, this means that some areas do not have sufficient sealer to fill the valleys. Applying additional light coats of sealer usually resolves this issue.
Question: Why do car tyres leave black marks on my sealed driveway? How do I avoid this and remove the existing tyre marks?
Answer: This is a phenomenon called "plasticizer migration." plasticizers are polymer compounds added to rubber, glue and plastic to make them flexible. The rubber used to make car tyres contains plasticizers to improve traction. But when the car is driven, the tyres heat up, causing the plasticizers to soften and leach out of the tyre. When a hot tyre is parked or driven on certain types of sealers, the plasticizers migrate into and discolor the sealer. The better the tyre quality, the higher the quantity of plasticizer —and the greater the chance for hot tyre marking. Lower-quality tyres are harder and contain less plasticizer , so they usually result in less hot tyre marking on sealers.
If switching to harder tyres is not in the cards, then consider using a different type of sealer. When a sealer cures, the resins cross link, forming a sticky tangle, like a bowl of undercooked spaghetti. All sealers exhibit some degree of cross linking. The greater the cross linking, the denser the coating and the more resistant the sealer will be to hot tyre marking. Most hot tyre marks occur on acrylic sealers, which exhibit minimal cross linking. Using a higher-solids acrylic or a high-solids, highly cross-linked urethane or epoxy sealer will reduce hot tyre marking greatly. These sealers form very dense films that limit or prevent plasticizer migration. Striking a good balance of sealer durability and density will make all the difference when sealing driveways and garage floors.
To get rid of discoloration from hot tyre marking, cleaning the surface with a concrete degreaser may be all that's needed, depending on the level of discoloration. If the discoloration has migrated deep into the sealer, you may need to loosen the affected areas with a solvent or totally remove the sealer with a chemical stripper.
Question: Shortly after applying a solvent-based acrylic sealer, tiny blisters and bubbles appeared on the surface of the sealer. What are these, and how do I get rid of them?
Answer: According to several coating chemists, bubbles and blisters in sealers and coatings are always a concern. While they don't always occur, there remains a chance they can show up.
Most sealers with less than 100% solids cure by "evaporative technology." The liquid portion of the sealer (water, xylene, acetone, etc.) is used to make transport and application of the sealer possible. Once the sealer is applied, the liquid evaporates into the atmosphere leaving the solid plastic portion of the sealer on the surface. During the evaporation phase, the solid plastic gets hard.
It is during this curing phase that air and other gases need to escape. If the sealer dries too fast (such as on hot days), too slow (on cold days), or the top dries before the bottom (due to wind or sun exposure or being applied too thickly), the potential is there to trap gas and create blisters and bubbles. Picture air trying to move through thick maple syrup. When the syrup is cold, the air will move very slowly. Heat that syrup up a bit, and it thins, allowing the air to move much faster. Too much heat, and the syrup itself starts to cook.
As far as getting rid of the blisters and bubbles, there are three common remedies depending on type of sealer and how many and how deep the bubbles and blisters run. For solvent-based sealers, blisters and other surface defects can usually be removed with a solvent bath (wetting the surface with acetone or xylene). This sometimes works with water-based sealers, but testing first is always recommended. Sometimes simple surface blisters in a solvent system can also be removed just by applying an additional coat of the same sealer. Surface sanding and re-application of the sealer has also worked in spot applications. If bubbles run deep, then the sealer is usually on too thick, and a solvent bath along with back rolling may be needed. As a last resort, the surface can be stripped of all sealer, cleaned, and resealed.
Question: The finished colour on my surface differs from the colour swatch on your website. Why is this so?
Answer: Colours may vary from how they appear on our web page and should be used as a guide only.
Whilst every effort has been made to accurately match the colours represented on our website, CSW Coatings advises that there may be significant colour variation between our website and end product. These variations arise due to different computer monitors (make, model and technology of the monitor, as well as resolution, contrast and brightness control settings) in much the same way a scan will differ from an original image and a colour photocopy.
Furthermore, coatings can exhibit variation in perceived colour depending on gloss level (porosity of substrate) , application method (ie. brush, roller and spray give rise to different finishes), viewing angle and light source..
Components that go into the manufacture of tints can affect the perceived colour as some of the solvents and resins are amber in colour but they do not effect final colour unless inadequately mixed with base.
When a tint is added to a base the colour will be affected by the base itself. It can also be affected by how well the tint is stirred in that the greater the shear when stirring the better the colour development and subsequent opacity of the finish coat.
Question: My coatings colour does not look full bodied and looks translucent?
Answer: This indicates an inadequate mix.
Question: I have a colored, exposed-aggregate driveway. Over the years, the sealer has become more and more cloudy. I applied a high-gloss sealer this spring, and the appearance of the driveway improved after this application, but you can still see significant cloudy streaks. I think I need to strip the sealer and reapply. What are your suggestions? What products should I use?
Answer: After too many reapplications of sealer, there comes a time when the coating can no longer breathe. When this occurs, moisture builds up and condenses under the sealer, making it turn white and cloudy. It typically does not occur in all areas and often appears random and streaky. After time, the sealer can also start to delaminate (come away from the concrete or previous layer of sealer), which will only make the cloudiness worse.
It sounds like you have reached the point where you have too much sealer, and as you suspected, it is time to strip and start over. In general, a good-quality chemical stripper will do the trick. It may take multiple attempts to get it all off, depending on how many layers of sealer are on the slab. After stripping the sealer, scrub the surface with soap and water, followed by rinsing with clean water. Hot water is better if you can arrange it. Let the driveway dry for a minimum of 24 hours, then reseal with one or two thin coats of sealer.
Question: How do humidity levels and dew points affect sealer application over substrates?
Answer: A great way to get a handle on the concepts of humidity, dew point, and condensation is to look at your bathroom mirror the next time you shower. Run a hot shower for 10 minutes, and the bathroom will fill up with steam (water as a gas) due to high humidity. When that hot steam hits a cold mirror, it condenses as a liquid (dew point) on the mirror's surface.
This same process can happen with cold concrete/pavers/tiles, whether indoors or outdoors. But unlike a mirror, substrates act like a sponge and the condensed water will soak in. If the surface has been sitting open to the air for hours or days, the concrete may look dry and show no outward signs of moisture. However, if applicators go ahead and apply a sealer, they will trap in all that moisture, causing the sealer to turn white or hazy.
When sealing exterior concrete surfaces, remember that humidity and condensation are most often higher in the morning. Consider applying the sealer in the late afternoon or evening. When sealing interior surfaces, make sure there is enough air movement through the room or building to allow the floor to give up its moisture. Damp or enclosed environments obviously will hold more moisture, and pose a bigger potential sealing issue. Bring the floor up to temperature slowly before sealing.
Question: I have a friend that is a builder / painter / applicator etc and he says just by looking at my surface that the product has failed.
Answer: In this business experts are all too common. Unfortunately unless NATA approved, opinions mean very little.
Question: I applied a sealer on my surface and moss and mould has grown back.
Answer: Unfortunately no product exists to prevent the growth of water born contaminants like moss, mould, mildew etc. A sealer prevents contaminant spores permanently embedding to substrate thus making maintenance substantially easier. Substrate will still need to be maintained.
Question: I applied a two-part solvent-based urethane sealer on concrete. In certain random areas, the sealer foamed and bubbled. What caused this foaming, and how do I fix it?
Answer: Two-part urethanes are higher-end sealers for concrete. Not only are they nearly twice as thick as an acrylic sealer (3 to 5 mils), but they also produce a very durable and chemical-resistant non-yellowing coating. The two components are made up of a resin (Part A) and a hardener (Part B). When these two parts are mixed at the proper ratio, they get very hard, with the time of hardening depending on temperature and other environmental factors.
One thing a lot of applicators aren't aware of is that the polymer in the Part A resin reacts vigorously with water. The reaction creates bubbles in the sealer, which results in a frothy foam. (this is how foam for mattresses, car seats, and foam insulation is made). In this case, water must have been present in this area when the sealer was applied.
The fix involves using a strong chemical stripper to remove the affected area. Remember that urethane sealers have good chemical resistance, so a typical solvent- or water-based stripper will have little or no affect. Once you strip away the foamed sealer, slightly sand the area and its borders to prepare for sealer reapplication. Then clean the entire area with alcohol or acetone to remove any residual stripper, dust, and dirt. Reapply the same sealer to the prepared area, taking care to blend the new sealer in at the edges.
Question: Is it normal to still get marks on a surface that has been treated with an impregnating sealer?
Answer: Since impregnating sealers do not fill the pores, marks from a contaminating agent can still discolour the surface. The good news is that the sealer holds the contaminating agent close to the surface. Usually, a diluted acid free bleach and light scrubbing will remove most marks caused by organic contaminating agents such as oil etc.
Moisture is a leading cause of problems with sealers. Under certain conditions, moisture can become trapped in or under the sealer, resulting in whitening or clouding of the sealer membrane. But why does this happen, how do we avoid it and how do we fix it?
There are two key contributors to moisture problems. The first is sealer contact with moisture in the substrate during application. Sealers can't take much moisture contact. This is why they need to be applied after the concrete has cured for 28 days. If a sealer has been applied to green or wet substates you can pretty much guarantee the development of a nasty white haze. This has to do with the type of resin (or plastic) the coating is made from, and how that resin deals with moisture contact.
The second key contributor to moisture problems is the permeability of the sealer, or how readily water is able to pass through the sealer membrane. Permeability is directly related to the solids type and content and thickness of the sealer. All exterior acrylics are designed to allow some level of permeability when applied correctly. The lower the solids content and/or the thinner the membrane thickness, the more moisture that can pass through the sealer without getting trapped and turning white. This is why applying sealer at the proper thickness is so important, especially when dealing with high-solids-content products (in excess of 25%). The higher the solids content, the smaller the margin of error. Most of the moisture-related problems in the field are caused by over application of high-solids sealers.
In regard to avoiding moisture-related problems, it is really quite simple. Use a sealer with a solids content of less than 25% and apply it thinly by spray. If problems do occur, misting solvents over the surface, such as acetone, xylene or MEK (methyl ethyl ketone) followed by back rolling will spread out the sealer film and remove excess material. After the solvents evaporate, the sealer will reharden. In a worst-case scenario, it may be necessary to strip off the sealer followed by cleaning of the surface and sealer reapplication.
The Effects of Temperature on Sealer
The No. 2 cause of problems when applying sealers to substrates (after moisture) is temperature. Both air and surface temperature play a role, but surface temperature is typically more critical. After application, sealers undergo a chemical reaction that causes them to cure and form a film. Temperature plays a critical role in how fast or even whether this reaction occurs. The best temperature range for applying sealers is 10 to 28 degrees C (50 to 80 degrees F). That degree window is really not very big, especially when you're working outside. This is why monitoring weather conditions and looking at a thermometer should be mandatory before every sealer application. Here's what can happen if temperatures are too low or too high.
When temperatures are too cold during sealer application, a film won't form and you're left with a white, powdery residue.
Every sealer has a minimum film forming temperature (MFT), or the minimum temperature needed for the sealer to properly form its film, cure, and get hard. For most sealers, this temperature is around 5 degrees C (40 F) or higher. To be safe, most sealer manufacturers specify 10 C (50 F) to provide a buffer zone. If the temperature is at or slightly below the MFT, the chemistry of the sealer is affected, the reaction slows down, and you get partial to no film development. Bottom line: The sealer is weak and will not hold up very long. If the temperature is really cold, film development stops altogether and all you are left with is a white powder on the surface after the carrier (solvent or water) evaporates.
Temperature is a catalyst. As the temperature increases, so does the reactivity of the sealer. Increased reactivity decreases the working time, or pot life, of the sealer. The faster the reactivity, the less time the sealer has to wet out the surface, de-gas, and form its film. This makes it critical to get the sealer down on the concrete quickly and efficiently. As the temperature increases, the ability to roll out sealers becomes more difficult. We always recommend spraying solvent-based sealers, especially in warm conditions. A common indication that the temperature is too high is the formation of fine "spider webs" or "cotton candy" strings coming off the roller or spray tip. This occurs when higher temperatures cause the solvent to flash before the resin (plastic) in the sealer can form its film. The pressure from the sprayer or friction from the roller pulls the soft plastic into long, thin strands.
Another common issue caused by higher temperatures is the formation of bubbles or blisters in the sealer. They occur when the solvent flashes too fast, trapping gas and air in the sealer. With today's tightening VOC requirements more fast-flashing solvents are being used, which makes the window of application even smaller. When outside temperatures are expected to rise above the recommended application range, apply the sealer during the cooler times of the day, typically mornings and evenings
Dealing with Condensation on Sealers
We have covered how moisture and temperature can each affect sealer performance. But what happens when both come into play? Here's a mini lesson in meteorology to explain the problems that can occur when the two conspire. The air that surrounds us always contains water vapor, but the amount of water can vary. Humidity is the measure of how much water is in the air at any given time. We would not have to worry about this water vapor if it just remained trapped in the air as a gas. But it doesn't because temperature fluctuations convert that water vapor into a liquid. If temperatures rise and enough water is in the air, instability is created and rain can fall. As temperatures fall, condensation can occur in the form of dew. For example, on cool summer nights, you'll often see dew-covered cars, grass, and other surfaces once morning comes around. The dew point is the temperature at which water comes out of the air and becomes a liquid.
What does all this have to do with sealers and your surface? A lot, if not taken into consideration before sealing. As humidity increases and temperature decreases, water will condense on cool surfaces. Since most surfaces act like a sponge, it will absorb the condensation. The problem is that the slab surface won't look wet, but hiding just beneath it can be lots of collected water. If a sealer is then applied to the surface, the trapped water can cause the sealer to white out or not adhere properly. Outdoors, this problem is more common during transition seasons as nights get colder but humidity is still high during warm days. Indoors, this problem is prevalent in the winter near walls and doors where floor temperatures are colder.
Cold Temperature and 2 Pack Incomplete Cure
If incomplete cure is not the result of an inconsistent mix then variations in temperature will either speed up or slow down the curing process.
In general terms if substrate temperature (not air temperature) is cool and surface remains tacky/sticky then heated fans may be utilised to aid in the curing process.
Caution is advised against aiming fan directly at specific areas of coating and should treat room temperature uniformly to avoid "mud cracking".
If not wishing to employ heated fans then coating (subject to consistent mix) will eventually achieve Hard Dry cure after substrate temperature has remained above approximately 10 degrees (24-36 hrs). Overnight conditions must also be taken into consideration as can vary substantially from daytime conditions.
If only wishing to remove tacky residue from some or all application then a solvent wash may also be performed with xylene/mop/broom.
Ultimately temperature variations are specific to local application. As an example only, a suspended slab in a shopping centre will experience vastly different environmental variables in contrast to an enclosed garage floor slab or car dealership as drying times are generally related to air circulation, temperature, and film thickness.
Preparing Surfaces for Sealer Application
A simple but often overlooked step in any sealer application is surface profile. When we use the term "surface profile" in regard to sealing, we are including all aspects of the surface at the time of sealer application. But the two heavy hitters are cleanliness and porosity. Overlooking either can cause even the best sealers to fail.
Clean means just that: clean! A surface that is to be sealed must be free of all dirt, dust and any other contamination that will come between the sealer and the surface. Just spending a little extra time cleaning can make all the difference in how well the sealer adheres. In some cases, a good broom or blower is all that is needed to remove loose dirt. More stubborn contaminants may require removal by scrubbing with Moss, Mould and Mildew cleaners followed by a clean water rinse or acid etching followed by neutralization. I also consider residue from stain and dyes, excess release powder and efflorescence as surface contamination. These types of dry contamination are most often the culprits when sealers fail due to a dirty or contaminated surface. Efflorescence and stain residue are especially nasty because their extreme pH levels can affect sealer chemistry. A sealer that exhibits white "curds" in the film or soft spots is often failing due to a surface pH imbalance.
Porosity refers to the concrete surface's ability to take in the sealer. If the sealer can't wet out there will be little or no adhesion and durability. A hand-troweled concrete surface is usually porous enough to accept a one-part sealer with a solids content lower then 30%. A machine-troweled concrete surface will usually require additional prep to open it enough to accept the same sealer. Typical methods for opening a very tight or dense surface include light sanding or acid etching. When dealing with higher-solids sealers (usually two-part urethanes and epoxies with solids in excess of 45%) opening the surface or diluting the first sealer coat is highly recommended. A simple water test (to see how well the water wets out the surface) is a great way to determine if the surface is ready to accept the sealer.
Sealer Application Tips. Each type of sealer has a recommended applicator and coverage rate.
Choosing the Best Applicator. Simply using the right application tool won't guarantee good results. You also need to practice the proper application techniques to avoid bubbles, blisters, lap lines and other eyesores.
The most common application problem is applying too much sealer at once (remember the phrase "thin to win"). Sealers are designed to perform best at a specific thickness, depending on the type of resin. This is determined by the coverage rate for that particular sealer. A good analogy is to compare sealers to a deck or cards. The first and second cards dealt are close to the surface, hard to pick up and very stable. The more cards you put on the pile, the more unstable the pile gets. The same holds true for sealers. The first and second thin coats are very stable, have good adhesion and provide good durability. The more you apply, either in one or multiple applications, the more unstable the system gets. With solvent-based systems, the signs of overapplication are typically bubbles, blisters and white haze. With water-based systems, you'll often see blisters, foam and a milky white cloudiness.
Another common application mistake is lap lines, or uneven application. When applying sealer, always go back over the previous pass about 2 inches as you move across the surface. This overlap needs to occur when the sealer is still wet, so the two passes blend and become one. If the first pass dries, the second creates a lap line and can be seen after the entire floor is dry. Fixing the problem usually requires applying another full coat of sealer.
When applying sealer by sprayer (whether using airless or pump-up type) make sure to maintain constant pressure and use the proper tip. A cone-shaped spray pattern is better than a fan pattern, and the more atomized the sealer the better.
When applying sealer by roller, make sure to buy a roller suitable for the sealer type (water- or solvent-based) and a nap thickness appropriate for the surface. When rolling on water-based sealers, be careful not to over-roll, which can causing foaming and blisters. You also may need to dip the roller more often. Some newer acetone-based fast-drying sealers can't be roll applied because they flash off too fast.
When using a lamb's wool applicator, micro-fiber applicator, synthetic mop or T-Bar, the application process is the same. Pour the sealer on the surface, and push and pull the product while maintaining a wet edge until you achieve the desired thickness. These application methods are very good for water-based sealers because they don't foam and you can see the white sealer go clear as you push and pull it around the floor. However, they will only work on smooth floors.
Did The "Seal" Fail?
That can happen no matter what sealer was used. This does not mean the "sealer" lost its performance. It can mean the substrate:
has moved (base movement, thermal contraction/expansion) that breaks sealer bond.
cracked (large or micro-cracks not visible to the eye)
had contact with something that breaks down the sealer. This depends on the sealer formula catagory and usually can be determined from the sealer label.
had dust or other contaminents that interfered with the sealer bond and/or penetration.
is showing the eventual signs of a sealer application that was not done properly, or could not be done properly. For example:
a penetrating sealer applied as a coating and not enough liquid to penetrate down.
a substrate that was thought to be absorbent but was reduced or eliminated absorption (grouts modified with additives, tile that was pre-sealed prior to grouting, etc.)
something that interfered with the sealer's bond to the surface.
How Important Are The Temperature Limitations On Sealer Application?
Even though the thermometer says 25 degrees, the surface to be sealed can be 10 or more degrees higher (and vice-versa). All sealers will tend to dry faster than designed if applied to a hot surface. That could mean insufficient time to properly penetrate (and/or spread to a tough film) and bond.
If the surface temperature is too cold, the normal flowing and curing characteristics are also changed from what was designed into the formulas. The differences could also negatively effect penetrating and/or spreading.
Also, a water based sealer allowed to freeze can experience separation of the components. Thawing and remixing might not be sufficient to reblend.
Solvent base products are generally more tolerant of the effects of colder weather applications.
How Important Are The Humidity Limitations On Sealer Application?
It is not the humidity in the air that is the issue, but the moisture in the tile or stone. Humid air will only slow down the drying/curing somewhat, but the sealer will reach its normal hardness. However, do a small test patch to make sure there are no surprises.
Sometimes, despite your diligent research you might have the wrong information. Therefore, no matter how confident you are, whether first time user or seasoned professional, it just makes good sense to patch test a small area and evaluate the results in a few hours before doing a large area.
Do You Really Need To Strip The Old Sealer?
If the existing sealer is not well bonded to the surfacing, there is little point to putting anything on top of it. It will continue to lose bond over time and wear and peel from the surfacing. A good way to evaluate the quality of the existing sealer bonding is:
If there are already areas of peeling, it is reasonable to assume there will be others and the bonding overall is risky.
Use a piece of tape to see if you can lift the sealer from the surface. You should not be able to do this "forced peeling" if there is a good bond.
ALWAYS - ALWAYS - ALWAYS - PATCH TEST FIRST!
The immediate beauty and ability to bead water are not very important. Patch test and allow ample time to evaluate the results. Re-seal projects are potentially so touchy that a test area should be evaluated after a month or more during which the flooring has been subjected to all future abuse including traffic wear, sun, heat, rain, sprinklers and maintenance procedures. Remember that a newly sealed surface always looks beautiful, but a marginal application of sealer under adverse conditions of weather, moisture, preexisting non-compatible sealer, etc. can be at high risk of future peeling. As with a new application, risk approaches zero if the correct sealer is selected and applied according to our directions.
Sealed Surface Has Dark Areas From Water Or Does Not Bead Water
There was not sufficient sealer applied. Just applying a sealer does not mean it is sealed. There must be enough quantity applied to do the job correctly. That is why results should not be determined by appearance, but by the water drop test.
Sealer Shows Marring, Scuffing, Scaring, Heel Marks
Try mild liquid abrasive cleaners or methylated spirits.
Penetrating Sealers Should Not Show A Build. If this is not done and the sealer is "painted" onto the surface in multiple coatings, there can be too much buildup. This excess buildup can be "soft" because penetrating sealers are designed to be resilient and mostly below the surface.
With a solvent based type sealer you can usually apply thinner/methylated spirits to dissolve the buildup and allow it to penetrate as it was designed to do in the beginning.
Second Application Of Penetrating Sealer Pulling Up First
It is not being applied per the label directions. When a sealer is only "painted on" it is not properly penetrated and adhered. When the second application is painted on with a roller it can tend to pull up the first. Just start over, follow the directions and the new sealer will liquify the old. The new and old will then penetrate properly.
Solvent Based Sealer Shows Bubbles Imbedded
As a thick sealer penetrates into a very porous surface it will displace air which must migrate up through the sealer. If the surface is less absorbent than expected or the sealer is "painted" on instead of the way the label recommends - bubbles could form and be trapped. Application in very hot weather can also cause premature drying which does not allow time for the bubbles to migrate out. If the sealer is one of the "solvent based acrylics", new sealer will reliquify old sealer. Just apply more sealer per directions and allow air to migrate out. Thinner will also liquify this type sealer.
Sealer Dries To Varying Darkness On Flagstone Or Sandstone
These stones frequently have imbedded crystalline pockets that may be invisible until a solvent based sealer is used. This sealer darkens the softer stone, but not the crystal. Test first.
Sealer Shows Peeling
This can even happen if:
The sealer was not applied according to the label instructions "and" (not "or") the conditions of heat, rain, traffic, abnormal abuse, etc. are beyond the norm. Sealers are applied incorrectly many times, but they are formulated to allow for great variances in job conditions. The only times a failure exists is when extreme conditions are coupled with an application technique that was in opposition to the application instructions.
Sealer Shows White, Hazy Areas
There are numerous causes:
If it has shown up under a newly applied sealer, it may be residual moisture. It should disappear in a few days, IF there is no longer a source of subsurface water.
If it comes off on your wet finger - chances are it is Efflorescence.
When a sealer is peeling, the air gap between sealer and surface looks white and hazy. If you scratch it with a coin and the sealer peels off down to the flooring surface - it is not properly bonded due to incorrect application.
If if occurs during a situation of standing water - it may disappear after the water is allowed to evaporate out.
Spotty Appearing Areas
One cause can be an uneven first application. Depending on sealer type, the more saturated areas, once cured, can repel the next application. Where repelled it is light in color. Where not repelled and the second application penetrates, it will be darker at first. Once it all dries, the color should be even overall. With an uneven, spotty first application, if a puddle of second application sealer is allowed to dry on top, some will penetrate and some could remain on top. Use a third application, but this time according to the directions and everything should even out naturally.
A Discoloration of the Top Coat - a yellow or brown look.
Paint applied too thickly (more likely when using solvent-based paints).
In compatible system using more than one brand of product.
Top coating too soon for basecoat to cure sufficiently.
Parking a tyre on a surface before the coating has cured.
Abrade the surface adequately to ensure adhesion and apply a suitable coating system to manufactures recommendations. Adhesion is the responsibility of the applicator.
Lifespan as indicated may be achieved in many applications though application method, cleaning methods, substrate type, weather – exposure to elements and traffic will affect wear. The use of solvents, acids and alkalis will seriously reduce a sealers lifespan.
Adhesion Failure - Floor system breaks away from the surface.
Cement is weak – concrete layer can be found on underside of paint chip.
A contaminant on the surface at time of application
The concrete has not been prepared correctly and adhesion has not been achieved.
Remove unsound paint or contaminant, prepare to manufactures recommendations and re-apply paint system. Check the stability of the cement to ensure it is suitable for a paint system.
A densifier works by reacting with the free available lime content within ones slab. A simple test you can perform is an acid resistance test. The higher the pozzolan load in the floor, the lower the amount of free lime available and the more acid-resistant the concrete will be.
The denser and more acid-resistant the concrete is, the less a sodium silicate densifier will react. If the acid foams green on contact, you know you have plenty of free lime for sodium/lithium silicates to work with. This test will also reveal any polymer concrete or portland-free concrete you may encounter.
Oil Marked/Stained Acrylic Concrete Sealer
Film Forming acrylic sealers are a protective coating! They are designed for the protection and enhancement of concrete surfaces. An acrylic sealers task is to protect your substrate from permanent staining much like a polish on a car protects the underlying paint. They are still fine with repelling oils if attended to straight away. What industry has found, especially with any single pack acrylic, is repellency is severely diminished if coating was over applied. Solvents built too heavily on a surface remain trapped and this is what reacts with say an oil spill.
Our preference for application is sprayer as it reduces the potential to over apply. If this is not convenient then a 10-12mm nap roller is advised really stretching out the coats. In a nutshell, a thin coat is much more effective than a thick coat with much less headaches! Over application can also be avoided by sticking with a products specified coverage rates.
Patterned cracking in the surface of the paint film resembling the regular scales of an alligator.
Application of an extremely hard, rigid coating, like a solvent-based enamel, over a more flexible coating, such as a water-based coating.
Application of a topcoat before the undercoat is dry.
Natural aging of oil-based paints as temperatures fluctuate. The constant expansion and contraction results in a loss of paint film elasticity.
Old paint should be completely removed by scraping and sanding the surface.
Bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface.
Coating applied on an excessively hot surface.
Application of coating over a damp or wet surface.
Excess moisture escaping through the surface.
Exposure of coating to dew, high humidity or rain shortly after paint has dried, especially if there was inadequate surface preparation.
Solvent entrapment due to inadequate recoat times.
If blisters go down to the substrate, first try to remove the source of moisture. Remove blisters by scraping, then sanding the surface. Allow to dry
Test for moisture levels and reapply coating when suitable. Use ASTM D4263 test.
A moisture barrier may be required if water vapor transmission rate to high for coating
Formation of fine powder on the surface of the paint film during weathering, which can cause colour fading. Although some degree of chalking is a normal, desirable way for a paint film to wear, excessive film erosion can result in heavy chalking.
Poor preparation on the abraded surface
Use of an interior paint for an outdoor application.
First, remove as much of the chalk residue as possible, using a stiff bristle brush (or wire brush on masonry) and then rinse thoroughly with a garden hose; or use power washing equipment. Check for any remaining chalk by running a hand over the surface after it dries.
The splitting of a dry paint film through at least one coat, which will lead to complete failure of the paint. Early on, the problem appears as hairline cracks; later, flaking of paint chips occurs.
Over thinning the paint or spreading it too thin.
Poor surface preparation, especially when the paint is applied to bare timber without priming.
Painting under hot or windy conditions that make water-based paints dry too fast.
It may be possible to correct cracking that does not go down to the substrate by removing the loose or flaking paint with a scraper or wire brush, sanding to feather the edges, priming any bare spots and repainting.
If the cracking goes down to the substrate, remove all of the paint by scraping, sanding then prime and repaint with a quality exterior coating.
Crusty, white salt deposits, leached from mortar or masonry as water passes through it.
Failure to adequately prepare surface by removing all previous efflorescence.
Excess moisture escaping through the exterior masonry walls from the inside.
If excess moisture is the cause, eliminate the source . If moist air is originating inside the building, consider installing vents or exhaust fans, especially in kitchen, bathroom and laundry areas. Remove the efflorescence and all other loose material with a wire brush, power brush or power washer; then thoroughly rinse the surface. Allow to dry completely and apply appropriate coating system. Moisture migration through surfaces can lead to mold and mildew growth and failures to adhesives, flooring coverings and coatings. Therefore all should receive a vapor barrier below the surface at source of moisture. Vapor retarders must have a permanence of less than 0.3 perms true vapor barriers are to have 0.00 perms to meet ASTM E96.
Fading/Poor Colour Retention
Premature and/or excessive lightening of the paint color, which often occurs on surfaces with a sunny exposure. Fading/poor colour retention can also be a result of chalking of the coating.
Use of an interior grade of paint for an outdoor application.
Use of a paint color that is particularly vulnerable to UV radiation (most notably, certain bright reds, blues and yellows).
Tinting a white paint not intended for tinting, or over tinting a light or medium paint base.
When fading/poor color retention is a result of chalking, it is necessary to remove as much of the chalk as possible (see Chalking). In repainting, be sure to use a quality exterior coatings in colours recommended for exterior use.
Appearance of a denser colour or higher gloss where wet and dry layers overlap during paint application.
Failure to maintain a 'wet edge' when applying paint.
Failure to use appropriate thinner or wetting agent during application.
Maintain a wet edge when painting by applying paint toward the unpainted area and then back into the just-painted surface. This technique (brushing from "wet to dry," rather than vice versa) will help produce a smooth, uniform appearance. It is also wise to minimise the area being painted and plan for interruptions at a natural break, such as a window, door or corner. Solvent-based paints generally have superior wet edge properties.
Loss of paint due to poor adhesion. Where there is a primer and top coat, or multiple coats of paint, peeling may involve some or all coats.
Excess moisture escaping through the exterior walls.
Inadequate surface preparation.
Applying a solvent-based paint over a wet surface.
Earlier blistering of paint (see Blistering).
Try to identify and eliminate the cause of moisture (see Efflorescence and Mottling).
Prepare surface by removing all loose paint with scraper or wire brush, sand rough surfaces, prime bare timber. Recoat with appropriate coating system.
Poor Alkali Resistance
Colour loss and overall deterioration of paint film on fresh masonry.
Coating was applied to new masonry that has not cured for a full year. Fresh masonry is likely to contain lime, which is very alkaline. Until the lime has a chance to react with carbon dioxide from the air, the alkalinity of the masonry remains so high that it can attack the integrity of the paint film.
Allow masonry surfaces to cure for at least 30 days or until the ph level is at the recommended levels for the chosen coating.
Brownish or tan discoloration on the surface due to migration of organic stains such as iron or tannins from the substrate. Typically occurs on 'staining timbers,' such as redwood, cedar and mahogany, or over painted knots in certain other timer species. Also occurs within a concrete surface when an excessive amount of water passes through from below the slab.
Use of a primer that is not sufficiently stain-resistant.
Heat drawing excessive water vapor from below the substrate bringing the stain.
Correct any possible sources of excess moisture. This is not always possible to correct due to the problem existing from a porous substrate .
Use appropriate water vapor barrier prior to applying final coating – consult manufacture for an appropriate coating solution.
A rough, crinkled paint surface occurring when paint forms a 'skin.'
Paint applied too thickly (more likely when using solvent-based paints).
Painting a hot surface or in very hot weather.
Exposure of uncured paint to rain, dew, fog or high humidity levels.
Applying the topcoat to insufficiently dried first coat.
Painting over contaminated surface (e.g., dirt or wax).
Scrape or sand substrate to remove wrinkled coating. Make sure the first coat or primer is dry before applying the topcoat. Apply paints at the manufacturer's recommended spread rate (two coats at the recommended spread rate are better than one thick coat). When painting during extremely humid, cool or damp weather, the applicator should allow extra time for the paint to dry completely.
There is always water vapour passing through concrete into the air, and sealers must remain permeable (breathable) enough in order for that water vapour to pass through them. If sealers are applied too heavily, they lose that permeability and the water vapour does create a kind of hydrostatic pressure.
This results in whitening as small bubbles are formed under the sealer, disbonding that area from the concrete. If enough of this occurs, delamination or peeling can occur. Solution Acrylics can be repaired by using a xylene (or xylol) wash to reform the sealer, and allow it to redeposit on the concrete. Other cross linking coating would have to be removed.
The only reliable prevention is to apply solution sealers as closely as possible to spread rate. Unfortunately, many customers believe that if a little is good, then a lot has to be better and then blame the sealer when problems occur.
As the acrylic sealer abrades, it loses transparency. This may happen within a year after the sealer was applied. Like scuffing a varnished surface with sandpaper, acrylic concrete sealer will turn hazy if scratched. Simple foot traffic or even normal weathering will abrade acrylic sealer. It will at some point become dulled or damaged. Usually, the first suggestion is to re-apply another coat of sealer. This is often the wrong thing to do. Applying more sealer can sometimes cause problems.
In fact, probably the most common mistake when applying acrylic sealer is putting it on too heavy. This is done either by the contractor who originally sealed it, or by the homeowner attempting to maintain his concrete’s appearance. No matter who applies the sealer, it is a mistake to think that if a thin coat of sealer is good, then a thick coat is better. With acrylic sealer, a thin coat protects just as well as a thick coat, but without rendering the surface impervious to rising moisture. Yes, moisture rising out of concrete can cause as many sealer problems as moisture going in.
Because concrete is very porous, almost like a sponge, it absorbs moisture in a number of ways. For example, groundwater can wick into a concrete slab from the sides or from underneath. Rainwater can seep into cracks and crack control joints. Water vapour can be drawn from the atmosphere. In short, concrete will almost always contain some moisture. When the concrete heats up, this moisture wants to rise to the surface and pass through the sealer and into the atmosphere. Thinly applied acrylic sealer allows this to happen. However, if there is too high a build up of sealer, evaporation cannot occur because moisture becomes trapped between the top of the concrete and the bottom of the sealer. This makes the sealer turn white or cloudy, a phenomenon called “blushing”.
Although resealing atop hazy sealer might make coloured concrete look better initially, the problem will soon return and worsen. This is because the solvent in the fresh sealer temporarily breaks down the existing sealer, lets the moisture out, and “melts” the old sealer back onto the surface. Then, when the new sealer dries, the coating is twice as thick as before, and becomes even more impermeable to rising moisture.
So how can you tell if your concrete is still sealed and only needs rejuvenation? If when your dull concrete is viewed at an angle the surface has some sheen, it probably still contains sealer. If the surface is completely dull with no sheen at all, then you may in fact need to reseal. Another test is to thoroughly clean the concrete and allow it to dry. If you then place a drop of water on it and the concrete immediately darkens, the sealer is probably gone. If it beads, even for a few seconds, there is probably still sealer present and the concrete may not need to be resealed.
The most common problem with epoxy coatings is small pinhead size bubbles may appear sporadically over the floor or in honeycomb clusters. In most cases, the bubbles are caused by air entrapment during mixing Part A and Part B by mechanical means. If the mixing action is too aggressive, such as a power drill set at a speed of over 600 rpm, it will forms small entrapped bubbles that are harder to break.
When mixing with a power drill, make sure you set the speed between 300-500 rpm and use a spiral-mixing blade. Make sure that you move the mixing blade all around the inside edge of the pail from bottom to top to ensure proper mixing
If the coating is applied during cooler temperatures, especially if the coating is not preconditioned (kept outdoor in colder temperatures), there is very little chance that air bubbles will break before the material is set. This downfall ultimately leads to the formation of small bubbles at the surface of the coating after it is hardened. This can be prevented by applying the coating in warmer weather by or preconditioning the material (keeping it warm inside until use).
If the bubbles are so severe throughout the floor to such an extent that it must be repaired, sand the floor with 100 mesh sand paper using a belt-sander, then vacuum it and reapply the epoxy coating.
Blisters & Craters Formation:
Outgassing is the phenomenon describing the large bubble formation or blistering that occurs in the complete cured coating. Bubbles may appear in the coating surfaces after a 100% solids epoxy is applied to a porous concrete surfaces. This condition is created when the epoxy begins its exotherm or curing action. The air in the voids of the concrete forces its way through the freshly applied coating. As the coating starts to harden, the air forms buckets that eventually break. When they do, they form large blisters. This problem is very dependent on the quality of the concrete itself and how porous it is.
To avoid or minimize the outgassing problem, seal the porous concrete with a thin solvent-based epoxy primer which due to its ability to penetrate deeply onto the concrete, can replace the air and seal off the concrete slab. This will not entirely eliminate the problem with poor quality concrete. Applying the epoxy coating in direct sunlight can also cause air bubbles to form because the heat of the sun will heat up the concrete. It is recommended that you apply it either in the early morning or later in the afternoon.
Repairing damages (blisters) of outgassing is somewhat complicated. Break the small size bubbles; fill large blisters with epoxy gel and allow it to cure to a hard surface. Sand this surface with 50-60 alumina grits sand paper to a smooth finish, then reapply the epoxy coating over it.
Poor Flow & Film Appearance:
This problem is happens as the coating is applied too hot or two cold or the ventilation of air flow is very aggressive. If the epoxy is applied when the temperature of the material is 30C/85F, the epoxy coating will cure so rapidly entrapped the bubbles onto it, may cause pigment fluctuation or separation or poor flow. At lower temperatures (15C/60F), the viscosity of the coating is very high causing poor flow and inability to level or release the bubbles. Excessive air movement through open doorways, from HVAC or other sources, may cause the surface to dry too rapidly or form a “skin’, preventing trapped air from being released from the coating.
Turn off HVAC blowers (if possible), or at least direct the air flow away from the newly applied epoxy coating.
Avoid high-temperature or low temperature condition whenever possible, cool or warm the product (precondition to room temperature) few days ahead of use for optimal performance.
Poor Adhesion & Peeling:
There are a number of reasons for poor adhesion of the epoxy to a concrete floor, including:
Faulty or insufficient surface preparation
Contamination of the material with oil, dirty solvent or dirty tools
Improper mixing of the two components
Wet or greasy floors
Excessive moisture, which will cause blisters in the epoxy surface that later peel away.
Disbonding from the concrete substrate is frequently associated with surface preparation. But it also could happen from excessive moisture on the substrates or from moisture vapor emissions. If this experienced within several months of the installation it is due to surface saturation affect from the dew point during installation. Aged floors which develop blisters are due to moisture vapor transmission or alkali aggregate reaction.
Providing that the damage does not cover the entirety of the floor, areas of poor adhesion can be defined by tapping over the area with a hammer. A hollow sound indicates lack of adhesion. A chain drag can also determine delamination in both concrete and coatings. Mark out the suspected areas a few inches outside the limits of poor adhesion and cut through the topping, then remove the damaged area by light mechanical hammers to establish the cause of adhesion. Make sure that the concrete is free of grease, etc., and reapply the epoxy coating. It is important to know that epoxies have relatively low peel strength and in instances of poor adhesion, attempting to remove the patch by chiseling can lift a large area of floor out, even where adhesion is still good. Such lifting can be limited by a “stop-cut”.
Inter-coat delamination is another form of poor adhesion. Applying epoxy coating over a previously applied coating may cause this, or applying the topcoat over the first primer coat after the 24hours window is elapsed (without sanding). If the recoat time has elapsed, then you will need to thoroughly sand or grind the concrete flooring, followed by removing the dust with a tack rag before you recoat your flooring. It is important, to always take time to test for compatibility/adhesion if you plan to reapply any coating. Also sand the epoxy coating if it old or have been applied in more than 24 hours previously.
Whether the cause was due poor preparation or moisture, the only way to correct poor adhesion is to sand blast the surface, removing all the flaking coating. In addition, if the surface that is to be coated shows any gloss whatsoever, the surface should be abraded using a medium to coarse sandpaper. Make sure that you remove any dust from the surface with a tack ragged or wipe the surface with a rag and strong such as xylene, prior to the applying the new coating.
If you have an adhesion problem that is throughout your entire floor, it is best that you shot blast the entire floor to the bare concrete, then following the instructions on the coating product, recoat the floor. Make sure however, that you correct any problems due to moisture. Many times, when left alone or ignored, blisters will expand or grow, as the more moisture accumulates underneath the surface of the epoxy. For this reason, it is important to note that if you are applying 100% solid epoxies, they should only be applied on-grade concrete floors that have a moisture barrier or another reputable poly-sheeting barrier beneath them. In addition, you can use a moisture meter to test for moisture content prior to application.
Tacky Surface or Soft Patches:
Surface stickiness and poor hardness are symptoms of improper mixing or incomplete cure. This problem is caused either by improper mixing of A to B or the failure to do adequate blending of the two component. The coating will remain tacky or gummy for so many days after the cure and will never cure. If after the sufficient amount of curing time has passed, your epoxy coating still has not hardened, or has a tacky feel, the problem more than likely is that no catalyst occurred. Unfortunately, this happened because the Part B was either not added to the Part A prior to mixing, or the right proportions were not mixed together.
To fix this problem the coating must entirely removed (using scraper) then clean with excessive amount of solvent such as xylene. Let it dry and reapply the coating.
Do not invert the buckets to try to drain the last drops of materials onto the concrete. There is a risk that the bucket wall or bottom will hold a non-mixed component.
Amine blushing can cause both surface tackiness and loss of gloss, although the coating is firmly cured. Amine blush is a normal chemical reaction between the amine present in epoxy with carbon dioxide and moisture in the air forming carbamate which appears as a greasy surface film. This can happen in conditions of high humidity or in close proximity to water source while the material is still curing; this is especially true at low temperature and high humidity.
The blush will prevent a good intercoat bond and may cause fisheyes during installation of the subsequent coat. It must be removed. In some occasion, the blush looks oily or has white residues. These white residues can either be removed with a vinegar solution (diluted with water).
It is recommended to sand the floor and reapply the coating to ensure a glossy finish since this treatment will remove the gloss as well.
Lack of Uniformity:
This is has to do with a technique rather than with the material itself. If you are not experienced in doing so ask our professional flooring guys to help you out. Lack of uniformity is also caused by poor premixing of component A (containing the colorants). Avoid over-rolling the coating and apply it evenly and at the right thickness. Another reason for discoloration is back rolling or excessive rolling after the material starts to set. The lack of uniformity or film defects can also occurred by excessive airflow, which causes the epoxy to dry too quickly. This usually happens with too much air is allowed to flow over the floor through open doorways, from HVAC or other sources. Another cause of bubbles is due to excessive heat, usually caused by heaters or applying the epoxy coating during extreme weather.
To prevent this simply turn off your HVAC blowers, if this is possible. If it is not possible, then try to redirect the airflow away from your newly applied epoxy coating. It is important to avoid high-temperature conditions whenever possible.
Imperfections and Fish Eyes:
Fish eyes are imperfections in the surface of the epoxy coating, which resemble the fish eyes. Deposits of residual silicone on the surface of the floor cause this type of imperfection. To avoid this type of imperfection, make sure that you properly prepare the concrete surface with the recommended solvent or stripping agent to remove any silicone contaminants. Any petroleum-based lubricant as well as any form of oil or grease including that from food products will cause surface problems, which will cause the epoxy coating to improperly bond. Another cause for fish eyes is to apply epoxy coating over still tacky (not fully dry or uncured) epoxy primer. The third cause of fish eyes the use of mineral sprit either for cleaning the floor or as a thinner. Mineral spirit is not compatible with epoxy coating.
To prevent any problems make sure that you remove all petroleum-based contaminants with an Oil & Grease Emulsifier, followed by a thorough chemical cleaning with caustic, acid, and detergent, test the concrete surface for contamination from an oily substrate by sprinkling with water. If it beads up, steam clean or torch to bring the contaminant to the surface, and chemically clean again.
The only way to repair fisheyes or other imperfections caused by oil or grease residue is to thoroughly sand the surface of the area, then following the steps, thoroughly clean the area again, making sure that you remove the silicon, oil or grease. Before you recoat the area, make sure that you go back over the area with a vacuum or clean the area with a tack rag to ensure that you remove all debris. Before you recoat your entire floor, only apply one unit at a time to monitor to see if the fish eyes reoccurrence.
Lack of Gloss or Dull Finish:
The most common cause of a dull finish is excessive humidity, which is humidity of above 60%. A dull finish after more than 24 hours can be due to moisture condensation during the cure. For this reason, epoxy coating should not be a task performed on rainy days. It is always better to wait for less humid weather. Other causes of a dull finish are improper mixing and/or applying the epoxy coating when either the air temperature or surface temperature of the concrete is cold. It is important to note that excessive humidity that which is above 60% and/or cold temperatures can cause blushing.
Lumps, Bumps or Globs in the Surface:
Sometimes no matter how well you sand, rinse, and clean the concrete surface, you will still discover lumps, bumps, or globs in the dried surface. These lumps, bumps, and globs of often lumps of 100% solids epoxy caused by poor mixing or from using dirty equipment when mixing or applying the epoxy coating. Lumps can also come from lint from the roller sleeve that you use. Always use a lint-free 6 mm roller. Another cause of lumping is when part A has been frozen. If you live in a cold climate area, make sure that part A is completely thawed for 3 days hours, and then you want to blend it thoroughly before using.
If you have bumps, lumps, or globs in your epoxy coating, to correct these imperfections is to sand or grind out the imperfections and then recoat the areas.
Whiting or Cloudiness:
An epoxy coating which appears white or cloudy immediately after installation has most likely been exposed to water prior to a complete cure. The exposure may be due to moisture from the concrete or substrates, moisture from the environment conditions (Dew Point), or from placing the coating into wet service prior to complete cure
Complete Damage & Disintegration:
This is a rare occurrence and only happens upon exposure to severe chemicals, particularly before achieving a full cure. Harsh chemicals such as acetone, methyl ethyl ketone, glacial acetic acid, paint stripper and benzyl alcohol should be kept away from the floor since the damage is irreversible.
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