Customer again... Quad forms seal with flashing (under siding) & concrete porch. Algae on porch/siding. Wash area with bleach/water okay? Not harm?

In most situations you should not have a problem but because one surface is concrete (a porous material) there would no guarantee that damage to the seal may or may not occur long term. Unfortunately, the QUAD Sealant is not classified as chemical resistant. What is important to know is that all sealants require maintenance at some point, and sometimes replacement, because of the effects of aging or, because of poor joint design or installation deficiencies that can cause premature failure including but not limited to the use of chemical cleaners.

In most situations you should not have a problem but because one surface is concrete (a porous material) there would no guarantee that damage to the seal may or may not occur long term. Unfortunately, the QUAD Sealant is not classified as chemical resistant. What is important to know is that all sealants require maintenance at some point, and sometimes replacement, because of the effects of aging or, because of poor joint design or installation deficiencies that can cause premature failure including but not limited to the use of chemical cleaners.