Just stumbled onto this
http://www.amesresearch.com/wall_coatings.htm
"Ames' Block & Wall is an elastomeric waterproofing sealant for exterior, above-grade walls. Block & Wall dries to form a waterproof seal to keep water and moisture out. This product expands and contracts up to 700%, is highly resistant to cracking and peeling, and remains flexible at -35°F. Block & Wall is ideal for block walls, basement walls, stucco and many other surfaces. It is heavy duty, yet easily applied by brush, roller or sprayer. Block & Wall was developed for cold and wet weather, and it is formulated to resist fungus, mold and mildew. This product is potable water compliant. Block & Wall cleans up easily with water."
Checkout the cardboard boat video. This stuff is tough.
http://www.amesresearch.com/wall_coatings.htm
"Ames' Block & Wall is an elastomeric waterproofing sealant for exterior, above-grade walls. Block & Wall dries to form a waterproof seal to keep water and moisture out. This product expands and contracts up to 700%, is highly resistant to cracking and peeling, and remains flexible at -35°F. Block & Wall is ideal for block walls, basement walls, stucco and many other surfaces. It is heavy duty, yet easily applied by brush, roller or sprayer. Block & Wall was developed for cold and wet weather, and it is formulated to resist fungus, mold and mildew. This product is potable water compliant. Block & Wall cleans up easily with water."
Checkout the cardboard boat video. This stuff is tough.