Concrete Foundation Walls - Water Leakage

Problem: Humid, damp, or, musty basement or crawl space - 1.

Cause: Entry of soil vapor through cracks in the floor slab or foundation walls.

Airborne vapor transfer can occur through both foundation walls and basement slabs. Air can move through porous soils or granular fill into buildings through cracks in walls and slabs and through weeping tile systems into houses, carrying soil moisture into the occupied spaces. Radon and other soul gases can also be carried into houses along these unsealed air paths.

Solutions: Ensure that foundations, slabs and all connections are airtight.

• Minimize cracking in floor slabs and foundation walls by using good mixing, placement and curing techniques.
• Seal the joint between the floor slab and foundation wall with durable caulking - either a single-component or extended polyethylene from below the slab-on-ground up the wall as shown in Figure 29.

Figure 29 - Extending Polyethylene From Below Floor Slab

• Make sure that air is not leaking into the building around the floor drains. Install a trap primer to ensure that the trap at the floor drain never dries out as shown in Figure 30.

Figure 30 - Potential Sources Of Air Leakage

• Ensure an effective seal around sumps, using a tight fitting cover.