We are located in St. Louis and use masonry extensively in mid-Missouri. Weather conditions vary from very hot, humid to quite cold and wind driven rain conditions. We refuse to use single wyth masonry block based on previuos experience and wall type failure to prevent moisture migration through the block to the interior surface. Past efforts to apply water resistent coating (water proof is a misnomer), have not held up over time. Although coatings will suffice for a period of time, we have found that the moisture will eventually migrate through the block and cause paint failure at the interior. I suppose if the Owner is prepared to regularly apply new coating, it is an option. Although the wall type can be very economical, the Owner should be made aware that there is a very high probability that mositure migration will occur. We have not used any CMU with water repellent added to the block mix.
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Bruce Dell AIA
Hoener Associates, Inc.
Saint Louis MO
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