I bought this for a old red clay brick wall that let water treu the bricks and mortar. After many research I found this product had all the requirements I was looking for. First I repaired all the cracks in the mortar and after everything was dry I used a leaf blower to remove all the dust and loose mortar. Then I taped all the wood and windows off. And followed the instructions. After I applied the sealer and let it dry the red clay brick wall was a little bit darker and it looks much better now with the sealer on it. We have had a lot off rain and no water came treu the bricks and the mortar and the bricks were dry on the inside. The sealer really works good as long you follow the instructions!! I will definitely use the product again for my customers.