How to Assure a Dry, Safe Foundation

Each year, owners of recently-built homes spend countless hours complaining to their builders about their basements, and the leaks, dampness, mustiness and mold growth problems that crop up due to moisture.

Many believe that their moist or wet basement issues are due to faulty concrete walls or failed waterproofing, when in fact, their foundation was never waterproofed properly.

Due to inadequate and poorly enforced building codes, many basements are merely built to pass, and are often treated with low-cost dampproofing, or water sealants – or even less.

Unfortunately, this is an area where some builders cut corners because homeowners cannot easily see the finished product, and the foundation is often covered by dirt early in the building process – out of sight, out of mind.

Dampproofing was never designed to protect walls from water leakage. Dampproofing is a low-cost product applied paper thin to foundation or cavity walls to retard the infiltration of water vapor into the living space area.

Dampproofing is thin and brittle – usually 10 mils thick – and doesn’ t have crack bridging capability or the integrity to resist hydrostatic water pressure.  So when walls start to settle, shrink, and crack, dampproofing cannot expand to bridge cracks and it opens up to allow water infiltration.

When water builds up along a foundation wall, hydrostatic pressure is created that, if not relieved, will penetrate through dampproofing to saturate a concrete wall and penetrate cracks.

There is a vast range of clear water repellants and sealants that call themselves “ waterproofing.” Generally, these clear products either penetrate concrete or block concrete pores, and function as a topcoat, but will not make a basement waterproof.

These repellants are more suitable for garage floors, and for above-grade anti-graffiti applications. For effective below-grade foundation waterproofing, clear products are sub-standard, at best.

For effective foundation waterproofing, the most common material is asphalt, modified with various elastomeric polymers that form a tough film that can stretch and bridge cracks. The ability to bridge cracks is extremely important as a house ages and the concrete foundation cures and cracks.

Foundation waterproofing is applied at 4-6 times the thickness of a dampproofing, and its cured film bonds tightly to the foundation wall. It provides a tough and highly elastic barrier to resist hydrostatic pressure, to prevent the infiltration of water and moisture vapor through the wall.

To expand on the performance characteristics of a high-quality waterproofing membrane, a high-quality drainage board and drainage tile along the footer and foundation wall can be installed to protect the coating, and to help channel rainwater and snow runoff into a sump system and away from basement walls.

Though more expensive than dampproofing or clear water sealants, the long term cost of applying a crack-bridging foundation waterproofing membrane is significantly lower when compared to the cost of digging up a leaky foundation for repair and replacement of structure and contents.

Beyond these structural implications, the health hazards created by moisture infiltration, mold and mildew, can cost many thousands more.

To summarize, foundation waterproofing can keep a basement dry and safe for many years to come.

Why would you settle for anything less?