Concrete Waterproofing Solutions for Commercial and Condo Buildings

To prevent water infiltration into foundations, roofs, and walls, concrete waterproofing is necessary. For commercial and condo buildings, this is a crucial part of the construction process, and the use of specialized materials helps protect against water damage. Here are some key issues and strategies when looking for concrete waterproofing solutions. 

What Is Concrete Waterproofing

Concrete waterproofing is the process of protecting concrete structures, making them impermeable to water. For commercial waterproofing and condo waterproofing, coatings, admixtures, and membranes are used during the construction process to seal surfaces, protect against freeze-thaw cycles, and enhance durability. Waterproofing and foundation protection can help reduce maintenance and avoid costly repairs in the future. 

Why Waterproofing Matters for Commercial and Condo Buildings

For commercial and condo buildings, waterproofing is critical as it ensures structural integrity and is a key preventative measure against water damage, lessening future expensive repair work, and ensuring safety standards. 

The porous nature of concrete makes it susceptible to the freeze-thaw cycle and other environmental stresses. Cracks from environmental stresses can lead to corrosion of steel reinforcements, structural instability, and encourage mold growth.

Common Waterproofing Problems and Causes

Common problems related to waterproofing failure include mold buildup, cracks, moisture infiltration, and leaks. This can be caused by many factors, such as the use of improper or incompatible materials, poor installation, failure to provide proper drainage, and overall improper surface preparation.

Key waterproofing problems

• Structural cracks and spalling. These are caused by steel corrosion and the expansion of rust that can crack concrete.
• Moisture and water infiltration. This can lead to leaks in the foundation, walls, and roofs. Water vapor can also accumulate on surfaces with temperature shifts and poor ventilation.
• Mold and mildew buildup. This is caused by trapped moisture and humidity.
• Efflorescence. The white, powdery stains that appear on the surface are caused by salt deposits forming on the surface when moisture seeps through small cracks and evaporates.

Key causes of waterproofing failure

• Poor preparation. Cleaning the surface is vital, and if the substrate is wet or covered in dirt or other contaminants, this can prevent proper adhesion. 
• Poor installation. The improper installation of membranes and not adhering to proper curing times can lead to waterproofing failure.
• Improper materials. Installing incompatible products can lead to poor bonding.
• Improper drainage. Water around the foundation increases pressure on the foundation.

Types of Waterproofing Solutions Explained

To prevent water ingress and structural damage, concrete waterproofing solutions should be utilized. Foundation protection is crucial. The right waterproofing solution will depend on whether the structure is new or not, and whether the application is above grade or below-grade.

Integral waterproofing

The concrete itself becomes a water barrier through the use of compounds in the concrete mix.
Integral waterproofing is ideal for new construction for permanent protection that resists wear.

• Hydrophobic admixtures are water repellants that reduce water permeation by coating capillaries, the microscopic pore networks formed during curing with hydrophobic substances such as oil or fatty acids.
• Crystalline admixtures react with water, forming insoluble crystals that fill the porous concrete material and microcracks.

Liquid applied membranes

Liquid applied membranes are used for hard-to-reach or irregular surfaces.

• This form of liquid-applied waterproofing is applied by spray, trowel, or roller, forming a seamless rubber-like coating.
• Polyurethane (PU) liquid membranes are useful for their elasticity and UV resistance. Used most often on roofs and balconies.
• Acrylic waterproofing is water-based and UV-resistant and is used for roofs and external walls.
• Bituminous coating, also known as liquid asphalt, is an inexpensive option providing a thick and durable coat. This is used most often on foundations due to its water resistance. 

Sheet membranes

These provide a consistent surface thickness and are ideal for large surface areas.

• These are manufactured rolls applied to concrete surfaces and are uniform in thickness. 
• Bituminous membranes are self-adhesive and used for roofs, foundations, and basements. 
• PVC/EPDM membranes come in flexible sheets used for flat roofs and as waterproofing liners.

Other waterproofing solutions

There are a few other solutions that should be considered. 

• Bentonite waterproofing consists of sodium bentonite clay panels used for below-grade waterproofing applications, contracting when coming in contact with water.
• Silicate-based sealers, or densifiers, are used penetrate the concrete to fill pores, and are commonly used for basement floors and walls. 

Comparing Membrane vs Liquid Applied Systems

These are the critical differences between the two systems. Each project will potentially require a different system.

Feature	Sheet Membranes	Liquid Applied Systems
Thickness	Uniform, factory-made thickness	Thickness can vary depending on application
Best For	Flat surfaces, high-traffic areas, large surfaces	Complex applications, vertical surfaces
Durability	Highly durable	Good durability with flexible performance
Installation	Requires skilled labor for consistent and accurate seaming	Easier to apply, especially in small or detailed areas
Seams / Overlaps	Requires seaming; overlaps are necessary	No seams or overlaps; creates continuous barrier
Moisture Protection	Effective moisture barrier when properly sealed	Continuous moisture barrier with no overlap
Flexibility	Less elastic compared to liquid systems	Superior elasticity
Application in Tight Areas	More difficult in nooks and small spaces	Easy application in nooks and small areas
Cure Time	No curing time required after installation (once installed)	Requires longer cure times

Sheet membranes 

Sheet membranes have a uniform thickness and are suited for flat, high-traffic areas and large surfaces. Its advantage is consistent factory-made thickness, and it is highly durable. It requires skilled labor for consistent and accurate seaming. 

Liquid applied systems

Liquid applied systems are best for complex applications and for vertical surfaces. They create continuous barriers for moisture prevention, with no overlap. 

It provides superior elasticity and easy application in nooks and other small areas, but the thickness can vary. It also requires longer cure times.

How Waterproofing Prevents Structural Damage

By sealing pores and cracks, waterproofing stops water ingress. This prevents steel corrosion and protects during freeze-thaw expansion cycles. 

As a protective barrier, waterproofing reduces long-term maintenance costs, extending the lifespan of foundations and other concrete structures.

Installation Best Practices and Considerations

A comprehensive approach that focuses on surface preparation and the proper materials for the local environmental conditions is crucial. In new buildings, this should be planned during the design phase.

• Surface preparations require a clean surface, free of any dust, dirt, oil, or grease, and any loose particles on the surface. 
• The concrete must be dry for many membrane systems for proper adhesion. 
• Any cracks, holes, and joints require filling with hydraulic cement or epoxy injections.
• The use of a compatible primer will aid in adhesion and prevent air bubbles.
• For liquid systems, the second coat should be applied in an alternate direction.
• Pipe penetrations and other complex areas, such as corners, need extra attention.
• Proper drainage should be ensured through the installation of perforated pipe drains or French drains. This should be installed at the base for groundwater management.
• Sufficient concrete curing time needs to be observed before applying membrane systems. 
• Follow drying times between coats based on material guidelines from the manufacturer.