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April Showers: The Complete Guide to Waterproofing Strategies

With the heavy rainfall of spring upon us, this guide outlines the various waterproofing strategies to employ to keep the foundation of your building watertight.

As the saying goes, "April showers bring May flowers." While rain is essential for nourishing the Earth, it also poses a threat to your building's foundation. Water infiltration can lead to costly repairs and structural damage, such as weakening the foundation or mold and mildew growth. It is essential for property owners to implement waterproofing methods to protect their investments. In this article, we'll explore the importance of waterproofing to a building's foundation and the various strategies that EDA Contractors utilizes to keep the base of your property solidified. 

Importance of Waterproofing

Water penetration is one of the most common causes of damage to buildings. It can come as a result of anything from cracks in the foundation, a compromised roof, or gaps in windows and doors that allow water to sneak its way into your building. Water infiltration can lead to foundation issues, structural damage, mold growth, interior damage, and more. The results can be severe and costly, which is why it is vital to keep water out. Below are some of the foundation waterproofing methods that EDA specializes in.

EDA Waterproofing Methods

1. Blindside Waterproofing

Blindside waterproofing is a method used on below-grade structures, typically basements, that are located on property lines. This technique is employed when traditional waterproofing methods, such as positive-side waterproofing, are not feasible due to site constraints. Using this strategy, the waterproofing membranes are applied to the shoring wall of the structure before the foundation and walls are constructed. The membrane is applied directly to a soil support, which then adheres to the concrete once it is poured. Blindside waterproofing creates a barrier that prevents groundwater and soil moisture from penetrating through. The waterproofing membrane directs water that it encounters downward and away from the building. 

2. Foundation Waterproofing

Foundation waterproofing is a method used to protect the foundation of a building. Unlike blindside waterproofing, which is applied to the shoring wall, foundation waterproofing is applied to the exterior of a foundation wall below grade. As a result, this requires the surrounding area of the foundation to be excavated. There are various types of waterproofing materials used for foundation waterproofing, including liquid-applied membranes, cementitious materials, and the most common form, asphaltic membranes. The chosen material is typically applied in multiple coats.

To keep the waterproofing system protected during backfill, a drainage board or dimple mat is used. After everything has been installed, the soil can be backfilled against the foundation walls. This method creates a barrier between the foundation walls and soil moisture, preventing the deterioration of the structure's foundation and moisture-related issues that may arise in basements and crawl spaces.

3. Underslab Waterproofing

Underslab waterproofing is the process of installing a waterproofing membrane horizontally on grade before the concrete is poured. Prior to installation, the surface soil must be leveled and graded to ensure proper drainage. Then, a layer of gravel should be backfilled over the prepared surface. The waterproofing membranes are applied directly onto the gravel and will lay beneath the concrete slab. The two main types of membranes used for underslab waterproofing are prefabricated sheet membranes and fluid-applied membranes. Once in place, the concrete slab is poured. The heat and weight of the concrete bond with the membrane creating a watertight system. Underslab waterproofing blocks not only water and moisture from entering the building from the ground, but also harmful gases like methane and carbon dioxide. 

4. Metal Oxide Waterproofing

Metal oxide waterproofing, also known as crystalline waterproofing, is a system that uses formulated chemicals to create a waterproof barrier within concrete structures. Catalyzed metallic waterproofing treatment is the mixture of clean commercial pulverized cast iron mixed with a chemical oxidizing agent. This material, when mixed with cement and water, is applied to below grade interior spaces, most commonly elevator pits. Metal oxide waterproofing is applied as a liquid coating that can sprayed, brushed, or rolled onto the concrete surface. Once applied, the coating chemically reacts to any moisture within the concrete to form insoluble crystals, which grow and create an impermeable barrier. These crystals seal any cracks that develop over time, providing long-lasting protection.

5. Traffic Coatings

Traffic coating is a liquid applied material designed to protect concrete or wood surfaces from damage caused by the elements. These surfaces are prone to heavy pedestrian and vehicular traffic such as decks, balconies, parking garages, and walkways. Before applying traffic coating, the surface should be cleaned and free of any defects. Then, a primer is applied to the surface to promote adhesion between the substrate and the coating. Once dry, the base coat is applied. The most common types of traffic coatings used for waterproofing include epoxy, MMA, and cementitious. Additional coats may be needed depending on the desired thickness and durability. Lastly, a topcoat is typically applied to protect against sunrays and wear and tear. The base coat repels any water that in contact with the surface while the topcoat maintains the aesthetic. 


Don't let April showers ruin the start to your Spring. Investing in waterproofing strategies to protect your building is a smart decision that will save you plenty of headaches in the long run. Each method listed above serves a unique purpose in keeping your foundation watertight. By properly installing these waterproofing systems, owners can avoid expensive repair jobs and have confidence in the long-term integrity of their building.