Water Management Below Grade
Learn how Tremco's line of foundation waterproofing products were used on the exterior foundation walls at FHB House Kansas to contribute to an energy-efficient home.
Planning for moisture control is integral to the success of a comfortable and energy-efficient home. To manage water below grade, we applied Tremco’s line of water management and drainage system products to the foundation.
Tuff-N-Dri, Tremco’s spray-applied sealant that replaces traditional damp-proofing, was applied to the exterior foundation walls at a 60-mil thickness. When it cures out, it’s closer to 40 mil, but because of its elastomeric properties, if a failure in the foundation were to occur, water infiltration would be much less likely.
The second step in the Tremco process is the application of the Warm-N-Dri drainage board. We chose the 2 3/8-in.-thick board, which is a fiberglass free-draining board that also provides some impact protection during the backfill process to avoid scraping any Tuff-N-Dri coating off the wall. The product also gives the side benefit of some thermal resistance—essentially getting an R-10— so the basement’s going to be a little bit warmer and dryer because of the choices made so far.
To complete water management below grade, we installed the DrainStar Stripdrain system, which is a drainage dimple mat that goes against the base of the Warm-N-Dri product. DrainStar is a footing drain that replaces the traditional corrugated drain tile that you would put a sock on and then bury in gravel.
This product is different in that it does not require a backfill of gravel. It can function in concert with the Warm-N-Dri board to allow the free-draining water to move into that system and then be carried away from the foundation. We are still going to backfill with gravel because there are expansive soils in Kansas that essentially have fatty clays that can be a real problem for us by creating hydraulic pressure that pushes on the walls and creates potential for cracking. As a measure of best practice, we’re going to backfill with the 3/4-in. crushed gravel, and that’ll complete our strategy.