Waterproofing Below-Grade Structures To Prevent Water Damage

Whether the below ground level space of the construction project you’re working on will be used for communication conduits, utility rooms, service tunnels, storage, or parking, the performance of the area is crucial for the building’s function and the entire structure’s physical integrity. It must be insured against water damage as an important aspect of the structure’s foundation. To do this, thousands of dollars can be saved by using below-grade waterproofing membranes.

In order to ensure that buildings are safe and dry, one of the smartest solutions being used today is that of below-grade waterproofing products. The question of the most appropriate products to use, however, and the entire below-grade waterproofing process can be difficult to understand; particularly if you’re unfamiliar with the latest developments. On your way to becoming a knowledgeable, confident expert, you should find the following information useful.

Below-Grade Waterproofing – What Is It?

Occurring below ground level, to the walls of a building’s foundation, the application of membranes and coatings during the construction process is referred to as below-grade waterproofing.

When water management techniques are effectively paired with below-grade waterproofing, the below-grade building envelope is kept leak free, thereby greatly reducing lifecycle costs. Why is it crucial for this process to be used?

Shotcrete and concrete are porous materials. They can crack, over time, when building settling occurs. This can also happen when, on the below-grade foundation, water-exerting pressure occurs or exists. If underlying contamination exists at a site upon which a building is constructed, the creation of hazardous conditions can occur through the creation of methane gas or vapors. Groundwater and contaminated soil can migrate through imperfections in the concrete. Placing a barrier between the surrounding earth and the concrete, however, prevents water infiltration. The structure cannot be invaded by harmful contaminants if a robust barrier is used. This is one reason why it is so important to find below-grade waterproofing products that are of the highest quality.

Below-Grade Waterproofing Membrane Features

For waterproofing below-grade areas, two dominant types of membrane systems are used:

• Fluid applied membrane systems – These can be hot liquid applied, cold liquid applied, or single component.
• Prefabricated sheet membrane systems – These can entail elastomeric sheets, modified bitumen sheets, bentonite, or thermoplastic membranes.

Waterproofing Membrane Application Processes

For the application of waterproofing membranes, three different processes exist:

• Negative side waterproofing – When a building is being constructed, negative side waterproofing occurs if positive side waterproofing isn’t possible. To the inside of the building, the membranes must be applied for this process – but it isn’t always preferable. Reliability may be a problem.
• Blindside waterproofing – This waterproofing, a.k.a. pre-applied, occurs on the building’s outside wall face or building foundation. Before the wall is constructed, it is installed. Unfortunately, some application difficulties can arise.
• Positive side waterproofing – This type of waterproofing, a.k.a. post-applied, requires outside building face access and is installed after the building of the wall. Negative side and blindside waterproofing may need to be used because positive side waterproofing isn’t always possible.

Factors to Consider

When you’re trying to decide which membrane system, application, and product to use, some important dynamics must be considered. The following building site factors must be taken into account:

• Expansion joints
• Cracks
• Penetrations
• Detailing
• Building codes
• Structural integrity
• Insulation
• Drainage
• Temperature limitations
• Presence of contamination
• Depth to groundwater
• Construction methodology

Quality Is of the Utmost Importance

One would think that this goes without saying. But if you’re trying to save money, you may end up considering options that seem – at least at first – to cost less. Surely, you’ve heard the old adage: “You get what you pay for.” This is often the case, particularly in the world of construction.

Significant challenges are faced by builders, contractors, consultants, and architects where below-grade structures are concerned. However, regardless of construction methodology or site conditions, contaminant detection and below-grade waterproofing systems must be able to do the job correctly. A high-quality manufacturer will provide a product that offers top-of-the-line fluid applied membranes and fabricated sheet membranes.

A dependable, superior below-grade waterproofing system will offer the highest, most dependable constructability and protection. When choosing products, manufacturers, sealant dealers, etc., no matter what your project, it’s important that the best solution be presented. The right company will have a history of working with various preferences, site conditions, and teams to achieve the utmost in protection.

Preprufe by Metro Sealant

Preprufe 160R and Preprufe Tape can help with waterproofing.

Preprufe 160R is made of a thick HDPE film (high density polyethylene) as a composite sheet. It uses weather resistant coating and pressure sensitive adhesive. This product forms an integral, proprietary bond to poured concrete. While providing a robust barrier to gas, moisture, and water penetration, it was specifically designed to prevent migration of water. Some of its benefits include the following:

• Solar reflective – During construction, offers reduced temperature gain
• Impermeable – Perm rating <0.1 perms
• For all basement grades, BBA certified
• A complete stop to gas, moisture, and water is provided. Against the surrounding ground, this product physically isolates a structure.
• Offers fully adhered watertight detailing in the laps
• During construction, does not activate prematurely
• Over properly prepared compacted soil, this product can be placed directly. The membrane is not changed by ground settlement. This product offers a continuous bond to poured concrete.
• To the concrete poured against it, this product forms a continuous adhesive bond specifically designed to prevent the migration of water.

Preprufe Tape can be used in detail areas including various tie-ins, penetrations, and end laps. For damaged area patching, it can also be used. The width of the tape can vary, depending on the product (example: 8-inch width, 4-inch width). To apply, unroll the tape and, to the penetration or membrane, adhere the exposed pressure-sensitive adhesive surface.

Need Below-Grade Waterproofing?

If you need below-grade waterproofing to prevent water damage in the building you’re constructing, turn to Metro Sealant. We have a product that is designed to go behind the soil barrier and drainage board – on the inside. It prevents vapor and water from coming inside commercial buildings. Depending on the exact product, it can be used for either horizontal or vertical application.

Please contact us to find out more about Metro Sealant and the variety of products and services we offer. You can reach us by phoning 866-748-8949, or by using our convenient online form. Fill it out, send it in, and we will be in touch.