We have a bessa block chimney that I’ve applied two different penetrative sealers to, which have markedly decreased water penetration although a small amount still occurs in heavy driving rain. I wish to paint it with the paint ideally adding another layer of rain protection. Is your Concrete Paint Sealer water resistant and/or proof, and is it suitable to use on previously treated (but unpainted) bessa blocks?
It is important to note that penetrating sealers or single pack topical coatings are not waterproofers and are considered repellents. If requiring resistance then a 2 pack would be a more suitable option like: 2 Pack. If exposed to UV then options would be limited to 2 Pack Urethane. Mortar Joints may be a point of weakness due to their recessed nature if not completely sealed.
Unfortunately we have not tested on chimneys when exposed to heat.
Film Forming / Topical coatings can be applied to previously applied penetrating sealers that have not been highly built preferably sticking with same carrier. eg: solvent based penetrating sealer/solvent based film forming coating.
Please also see:
Can Your Product Be Applied Over My Existing Product? FAQ