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Left: Damproofing application. Note lack of waterproofing under
the snap-ties. These walls were inspected and approved for backfill.
Right: Damproofing that doesn't extend above the finished
grade elevation combined with heavy unclassified backfill.

CMU block walls were the preferred method of foundation construction on the east end through the late 60’s and early 70’s. CMU block construction is still used today on many homes, although poured concrete foundations have dominated the market not only because of the cost savings but time savings as well. Because CMU block walls are constructed in layers with mortar between each block, they can prove to be challenging at times to waterproof properly. The two illustrations below show examples of CMU block walls and improper waterproofing. Many of the products used to waterproof CMU block walls decades ago were asphalt or tar-based compounds. Although it is still widely practiced today, the process of tarring a foundation serves nothing more than damp-proofing. The problem with asphalt or tar-based compounds is that they become rigid and brittle over a short period of time and can allow water to seep into the joints of the CMU block walls. Because block foundations are more susceptible to movement from temperature differences between the seasons and moisture content, the waterproofing on block foundation walls should be flexible. Many of the membranes used today adapt well to block foundations with crack bridging and elongation properties. We offer many different coatings for both poured and CMU block foundation walls, ranging from trowel-applied surface coatings to the more advanced sheet-applied membranes.

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CMU block foundation deterioation due to an absence of waterproofing and freeze/thaw cycles.

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CMU block foundation with sanitary
waste line penetration w/o waterproofing.

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Above three photos: Water and mineral migration through a cmu block foundation
due to poor grading, drainage and complete lack of waterproofing.

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Left: Exterior waterproofing. Right: CMU block foundation with sheet applied waterproofing membrane.