Waterproofing Design + Consulting

From below-grade walls/floors to underground buildings, we know how to create sustainable, well-designed structures so you can avoid the headache of water damage. Waterproofing should be designed, specified and observed by experts of the highest caliber; let us take a look!

What’s at Stake

Water infiltration is one of the most horrific things that can happen to a building. When water infiltrates the structure of a building, it can be quite insidious. The structural integrity of a building can be severely compromised when water damage occurs in addition to environmental consequences. Therefore, building waterproofing is of the utmost importance, particularly in areas that are prone to medium to heavy rains and flooding conditions.

Building waterproofing can and should always be designed, specified and observed by a qualified waterproofing consultant. Leaks into sub-levels of a building are a common problem for building operators and managers. Air quality, such as radon and conditioning in terms of humidity levels are often an additional concern.

What is Waterproofing

Waterproofing is defined as the resistance to the passage of water under hydrostatic head pressure. Hydrostatic head pressure means water is present from underground water buildup. This pressure is greater in soils that don’t allow much water to flow away from a building, like clay and solid rock. Hydrostatic conditions are also present in many roofs, decks and various façade assemblies.

Waterproofing design and materials are available to suit the following various building site conditions:

Below Grade Walls

The walls of a building’s basement levels are sometimes protected against water seepage as space may be used as storage, parking or other occupancy use allowed by code.

Above Grade, Buried Plaza Areas

In many cases, plaza waterproofing is located above an occupied space buried under pavers, turf and other plantings. These applications are referred to as waterproofing projects in most cases and may have different assembly configurations and detailing methods than a conventional roofing assembly.

Above Grade, Surface Waterproofing Systems

Many types of coatings are applied to deck assemblies for auto and pedestrian traffic, sports surfaces and other applications. These coating systems are applied by CRCA Member Roofing and Waterproofing Contractors.

Underground Buildings

The horizontal lids (roofs) of underground structures are considered waterproofing applications because they are usually buried under some amount of insulation, drainage systems and soil or other toppings. As such, waterproofing materials, systems and details are used instead of typical roofing details. This is due to the unknown direction of water travel. Once a structure is underground, water may seep from above or be driven by water pressure upward towards the ground surface. Special Flashings and other procedures are necessary to produce a successful waterproofing project.

Dampproofing

Dampproofing is defined as the resistance of water in the complete absence of hydrostatic head pressure. Dampproofing materials typically will not bridge cracks in concrete that may occur during the life of a building. Dampproofing is typically used on residential or light commercial projects with limited budgets and offers little to no warranty to keep water out of your structure. Most Dampproofing products are sprays applied very quickly and applied thinner than waterproofing. Therefore, Dampproofing may be significantly less costly than waterproofing.

Since Dampproofing requires a near-perfect design and construction to ensure water never could create a hydrostatic condition, DTR rarely would recommend or specify this solution.

What is Waterproofing

In building construction, a structure needs waterproofing since masonry or concrete will not be watertight on its own (but can sometimes have waterproofed qualities with the help of additives). The conventional system of waterproofing involves sheet or liquid membranes. This relies on the application of one or more layers of membrane (available in various materials such as bitumen, silicate, PVC, EPDM, etc.) that act as a barrier between the water and the building structure, preventing the passage of water. Proper designs also incorporate a drainage plain and some sort of protection to keep the membrane from getting damaged in the construction process. Installation of a membrane system relies on an exacting application, presenting potential difficulties for less experienced installers. Problems with application or adherence to the substrate can also lead to failure.

Over the past two decades, the construction industry has had technological advances in waterproofing materials, including integral waterproofing systems as well as more advanced membrane materials. Integral systems work within the matrix of a concrete structure, giving the concrete itself a waterproof-ish quality.

There are two main types of integral waterproofing systems: the hydrophilic and the hydrophobic systems. A hydrophilic system typically uses a crystallization technology that replaces the water in the concrete with insoluble crystals. Various brands available in the market claim similar properties, but not all can react with a wide range of cement hydration by-products, and thus require caution. Hydrophobic systems use fatty acids to block pores within the concrete, preventing water passage.

New membrane materials seek to overcome shortcomings in older methods like PVC and HDPE. Generally, new technology in waterproof membranes relies on polymer-based materials that are extremely adhesive and capable of creating a seamless barrier around the outside of a structure.

Below Grade Waterproofing

Below-grade waterproofing is all about water management. Design a system that will endure the below-grade conditions, along with a system to remove moisture away from the waterproofing system quickly. When water is allowed to collect and build up, it creates a hydrostatic condition. The pull of gravity against standing water is relentless, causing the water to push and push hard against anything that restricts its movement. Enough hydrostatic pressure and you will have water intrusion into your building.

Once complete, below-grade waterproofing can be subjected to thousands of pounds of water pressure from the positive side (from outside coming inside). The difficulty arises when a membrane cannot withstand hydrostatic pressure from within the substrate and therefore fails. Water may enter below grade through various means such as joints, walls, or floors. Even small defects or improper installation of the waterproofing system can cause major problems and costs can be monstrous.

Various below-grade waterproofing systems, well designed and properly installed, can address these problems. There are many systems available of varying cost, effectiveness, and installation invasiveness. More critical building occupancies require multiple system solutions (many times referred to as a “belt and suspender” approach).

“Ask yourself, what is my level of tolerance for water intrusion into my new building?”

Have this discussion early with your Architect/Contractor and bring a Building Enclosure/Waterproofing Consultant onboard.

Showers & Tub Enclosures

Frequently, designers only think about the below-grade waterproofing needs of a building. For building owners of multi-family or mid to high-rise buildings and hospitality buildings…ask them if improper shower design and/or construction have cost them dearly in lost revenue and way too much in repair costs.

Involve your Waterproofing Consultant in the design, specification, construction inspection, and testing of your shower installation projects. Some municipalities have recognized how many of these installations are done improperly, and they now require a special contractor’s license for these installations. Waiting for your client to call you to tell you they have leaks is not the time to test. Removal of wall and floor tile to fix problems becomes a very expensive and lengthy process.

Building Facade

The exterior vertical face of a building, referred to as the building facade, is as important as the roof and the below-grade surfaces of your building. They are by far the largest surface areas that separate the interior environment from the exterior. These vertical assemblies serve a very important role in the life of a building. They keep rainwater and wind from entering your building, yet as properly designed and constructed assemblies, they allow for the walls to breathe (effects of vapor drive). Trapped water vapor or intrusion of water through the skin of the building can quickly lead to ideal environments for potential biological growth (mold), poor indoor air quality, unpleasant indoor odors, uncomfortable indoor humidity, and likely premature building structure failure.

Water Repellents

Proper treatment with water repellents, referred to as “hydrophobization” will successfully protect your structure. Many exterior surfaces are porous and absorb water to varying degrees. As water enters the surface it sets up conditions that can result in a variety of problems such as freeze-thaw deterioration, structural degradation, mold & mildew, and damage to the interior drywall, carpeting, and moisture-sensitive flooring.

Joint Sealants

Sealant selection and application are paramount to proper performance. There are many considerations in selecting the proper sealant including sealant type and color. The desired result should be a sealant system that is watertight, insulating, resistant to the effects of air pressure, compatible with other building components, and cost-effective.

Underslab Vapor Barriers

Water vapor drive is another problem associated with water intrusion, as it may exacerbate the spread of toxic fungi or mold in addition to causing premature flooring failures. The presence of mold may pose a health risk to the occupants. To manage humidity, vapor retarder or barriers must be properly designed and installed during construction to stop vapor drive through your concrete slabs on grade.

Below Grade Waterproofing

Design Assistance

Our technical involvement in the building specifications and product selection assistance services enables us to keep current with the many advancements and new products being introduced by product manufacturers. We maintain an ongoing review program of testing and analyzing new products and procedures to evaluate their usefulness to our clients’ needs.

This knowledge of the industry enables us to provide the most applicable specifications for our clients. In addition to providing the best specifications, our experienced technical staff can assist architectural designers in the most appropriate and effective details for our A/E clients’ projects. These designs are communicated utilizing plans, sections, and details.

Our documentation (specifications, plans, and details) is suitable for the Architect/Engineer to incorporate into their construction bid documents. No matter how extensive the details, or how applicable the specifications and drawings are, the success of any project is largely dependent on the execution by the contractor.

Because of the importance of the execution, we mandate that our A/E clients utilize our on-site quality control inspection and construction oversight services.