All COLORED block made in Florida Contains integral waterproofing. The assumption you MUST make is that if the block is not colored it will not contain integral waterproofing. EVERY block that is used in a single wythe installation SHOULD contain integral waterproofing --- even if it is going to be painted or sealed. So…. If you are designing a single wythe wall that does not contain integral color be sure to request integral waterproofing!! ONE more thing --- EVERY single wythe wall SHOULD be painted or sealed.
Remember – Single Wythe -- Integral Waterproofing --- Painted and Sealed -- ALWAYS.
The architect is specifying the product DRY-BLOCK by gcp applied technologies as an integral waterproofing admix to be added to the block that are to be covered with a direct applied stucco. Is this what the industry would recommend?
The masonry industry and the stucco manufactures in Florida clearly DO NOT recommend the use of an integral waterproofing agent in masonry to be covered with direct applied stucco. This is not specific to the DRY-BLOCK product but applies to ANY integral waterproofing agent added to the block during the manufacturing process.
The reason is simple - integral waterproofing agents negatively effect the bond between the block unit and the stucco coating. This bond is one of the most important aspects direct applied stucco coatings. The problem is that good stucco bond depends on absorption of cement and water, out of the stucco, into the pores of the block. The integral waterproofing agents are an excellent product for preventing exactly this type of water movement.
Integral waterproofing in the masonry is highly recommended for single-wythe masonry walls which are not covered with direct applied stucco. They would also be appropriate for masonry covered with stucco attached to lath that is then mechanically attached to the block.
In the case of direct applied stucco, the stucco itself is the primary waterproofing barrier protecting the wall. Stucco has proven itself an effective waterproofing barrier by both experience and testing.
Jerry Painter, FASTM
Don Beers, PE, GC