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How to Properly Waterproof Exterior Foundation Walls

A construction site is pictured. There are two homes being built, both in the beginning stages of construction.

Waterproofing is essential to protect your project’s foundation from water infiltration. When done correctly, it helps to ensure that the living space remains dry, healthy and structurally sound. This article will explore the importance of waterproofing below-grade exterior foundation walls and the best methods and products to achieve effective waterproofing.

Benefits of Waterproofing Below-Grade Exterior Foundation Walls

Prolongs the Life of the Foundation

The foundation of a home or building plays a crucial role in its overall structural integrity. It bears the weight of the entire structure, anchors it to the ground and serves as a barrier between the building and underlying soil. 

Over time, external elements like water can compromise the foundation. Waterproofing below-grade exterior foundation walls creates a robust line of defense against these threats to significantly prolong its lifespan. 

Here’s how:

Protects Against Freeze-Thaw Cycles

Water that infiltrates foundation walls and then freezes can cause significant damage. As water freezes, it expands. If this happens within the porous spaces of your foundation material (like concrete), it can lead to cracks. Over successive freeze-thaw cycles, the cracks can widen and jeopardize the foundation’s structural integrity. Waterproofing prevents water from entering in the first place by shielding the foundation from water.

Reduces Hydrostatic Pressure

In areas where the water table is high or where there’s significant groundwater movement, hydrostatic pressure can be a significant concern. This is the force exerted by water against the foundation. When water is consistently pushing against the foundation walls, it can lead to cracks, leaks and even wall buckling in extreme cases. A proper waterproofing barrier resists the pressure and helps to ensure that the foundation remains intact.

Mitigates Chemical Deterioration

Soil isn’t just dirt. It contains various chemicals and minerals, some of which can react with the foundation materials, especially if they’re constantly wet. Over time, these types of reactions can weaken the foundation and lead to deterioration. Waterproofing acts as a chemical barrier to help protect the foundation from harmful substances in the soil.

Minimizes Risk of Water Damage

Many foundation materials, like concrete and masonry, are porous. Constant exposure to moisture can lead to spalling, efflorescence and general weakening of the materials. Over the years, this can compromise the foundation’s ability to bear the building’s weight. Waterproofing ensures that the materials remain dry to help preserve their strength and function.

Prevents Mold, Mildew and Indoor Air Quality Issues

Mold and mildew primarily affect the indoor environment, but their growth can also signal a compromised foundation. Persistent moisture creates the ideal conditions for fungal growth, which can further weaken foundation walls. 

By keeping the walls dry through waterproofing, you can help prevent mold and mildew while avoiding the structural issues they can cause.

Maintains Property Value and Reduces Repair Costs

Waterproofing is an investment. A well-maintained, waterproofed foundation is attractive to potential buyers and can help reduce the chances of facing major repair costs in the future.

Factors That Affect Waterproofing Effectiveness

Soil Conditions and Water Table Levels

This close-up image shows rich soil with a green leaf lying on top.

The type of soil around your foundation and the level of the water table can determine how much water pressure is exerted on your foundation. Sandy soils, for instance, drain better than clay soils, which can affect how you approach waterproofing.

Climate and Precipitation Patterns

This image shows rain flowing off of a home’s roof. It is dark outside as the rain pours down.

In areas with heavy rainfall or snow, there’s a higher risk of water infiltration. Knowing the climate and precipitation patterns can guide your waterproofing strategy.

Foundation Materials and Construction Techniques

A person wearing a red hard hat and sweatshirt is walking on a construction site.

Different foundation materials react differently to moisture. Whether your foundation is made of poured concrete, concrete block or stone will dictate the best waterproofing method.

Preparing Foundation Walls for Waterproofing

Preparing your foundation walls for waterproofing is essential for ensuring the longevity of the waterproofing treatment. Proper preparation ensures optimal adherence to the waterproofing material for an effective moisture barrier. Here’s a step-by-step guide to adequately prepare your foundation walls for waterproofing:

  1. Inspect for damage: Look for cracks or spalling on the foundation walls.
  2. Clean the surface: Remove debris and old paint using a brush or power washer.
  3. Repair cracks and holes: Use suitable patching compounds or hydraulic cement.
  4. Address any efflorescence: Clean affected areas with DRYLOK® Concrete and Masonry Liquid Etch & Cleaner.
  5. Check the drainage: Ensure proper slope and consider adding or repairing gutters.
  6. Smooth out uneven surfaces: Use a grinding tool or sanding block to address any uneven surfaces.
  7. Choose the right time: Opt for dry weather conditions that will last for several days.

The Best Option for Exterior Foundation Waterproofing

A can of DRYLOK® Extreme Concrete & Masonry Waterproofer is pictured against a white background.

There are numerous waterproofing products in the market, but not all of them are created equal. According to a 2021 survey, DRYLOK finishes first in brand leadership for exterior foundation waterproofing during the construction phase. By merging superior protection with aesthetics and user-friendliness, DRYLOK delivers a product that meets the demands of modern homeowners and professionals alike. 

With a rich history of excellence, DRYLOK Extreme Concrete & Masonry Waterproofer stands out as a top-tier product for safeguarding foundation walls. 

Discover the Best in Concrete And Masonry Protection Products with DRYLOK

Don’t wait until it’s too late to protect your home. Invest in DRYLOK Extreme Concrete & Masonry Waterproofer today for superior protection against water infiltration and the peace of mind that comes with it. Get started on your journey to a safer, moisture-free home right away.

Contact us today to discover more about DRYLOK or to locate a store near you!