Strong, durable, and safe commercial buildings and homes rely on waterproof basement walls and floors to maintain their integrity and prevent long-term issues. The fundamental goal of basement waterproofing is to keep water and soil away from below-grade walls and floors. For concrete basement walls, this typically involves the installation of a waterproofing membrane and a dimple drainage board.
Without effective waterproofing, porous basement concrete can crack due to water pressure or structural settling, allowing groundwater, contaminated soil vapors, and insects to enter the building. The best waterproofing solutions create a moisture-free, below-grade building envelope, protecting the structure’s integrity, reducing long-term maintenance and repair expenses, and preventing common moisture-related problems such as:
- Structurally damaging and unhealthy mold
- Unpleasant odors in the basement
- Damage to interior flooring
- Crystalline deposits of salts (efflorescence) on basement walls or floor
- Outward or inward bowing walls
- Cracks in the walls
Polyguard’s Solutions for Basement Waterproofing
Polyguard, through its Residential Solutions division and its broader commercial offerings, provides comprehensive basement waterproofing products for both residential and commercial applications. Their solutions address waterproofing for:
- Basement Walls
- Basement Floors
- Basements from the outside (exterior)
- Basements from the inside (interior)
Polyguard’s products, including membranes for pre-applied and post-applied applications (fluid and sheet-applied), are designed to withstand challenging conditions and protect concrete basement walls from water and contaminant infiltration caused by concrete imperfections. They also offer solutions like the Polyguard Underslab Membrane for waterproofing interior basement walls and floors.
How Water Infiltrates a Basement
Water can infiltrate a basement through various pathways, leading to costly and complicated repairs. These pathways include:
- Door, window, and vent openings
- Hydrostatic pressures
- Wall penetrations
- Poor site drainage
- Concrete cracking and mortar joint movement
- Flooding
- High water tables
High moisture levels in a basement significantly raise indoor relative humidity, increasing the risk of condensation and the growth of unhealthy and damaging mold. Implementing waterproofing into a structure’s design can limit, if not stop, basement water intrusion. Protecting a home or building from basement moisture also involves identifying and addressing possible water transport mechanisms through the walls and floor.
Does a New Basement Require Waterproofing?
Yes, new basement construction absolutely requires waterproofing. The best approach for new basements involves implementing strategies to prevent liquid and vapor water infiltration due to hydrostatic pressure and capillary action.
- Hydrostatic pressure occurs when gravity pushes static water against exterior basement walls, especially those built on a slope or entirely or partially below the water table. This pressure forces moisture through cracks and joints and can cause water to permeate solid concrete through capillary action (wicking).
Code Requirements for Waterproofing a Basement
For reference, the 2021 International Building Code (IBC) (Section 1805) and the 2021 International Residential Code (IRC) (Section R406) specify the conditions that mandate either waterproofing or dampproofing a foundation.
- Dampproofing aims to prevent moisture in the soil from infiltrating the basement wall.
- Waterproofing, on the other hand, aims to keep water (liquids and soil moisture) away from the below-grade walls. For concrete walls, waterproofing specifically involves installing a waterproofing membrane and a dimple drainage board.
The best way to waterproof a basement must include both the walls and the floors. Adequate waterproofing of basement walls helps them resist shear and bending stresses from lateral water and soil pressures, ensuring they can support the structure’s weight, resist wind and seismic forces, and provide anchorage.
What is the Best Way to Waterproof Basement Walls?
The most effective way to prevent water infiltration into basement walls from hydrostatic pressure and capillary action involves installing an impermeable membrane and a drain board between the earth and the building.
Types of Basement Waterproofing Membranes
Manufacturers typically offer two main membrane systems:
- Prefabricated Sheet Membrane Systems:
- Materials: Modified bitumen, bentonite, thermoplastic, or elastomeric membranes.
- Application: These come as pre-formed sheets that builders can directly apply to surfaces.
- Fluid-Applied Membrane Systems:
- Types: Hot liquid-applied, cold liquid-applied, or single components.
- Application: Applied as a liquid (hot or cold) to properly prepared substrate surfaces, forming a seamless membrane.
Application Techniques
There are three primary techniques for applying waterproofing membranes:
- Negative-Side Waterproofing Membranes: Applied to the interior (dry) side of a building. Typically used only when positive-side or blind-side waterproofing is not feasible.
- Positive-Side (Post-Applied) Waterproofing: Applied to the exterior face of the building after wall construction. Requires external access.
- Blind-Side Waterproofing: Pre-applied to the exterior face of the basement wall before the foundation wall is built.
The Best Way to Waterproof a Basement Wall (General Principles)
The best way to waterproof a cinder block basement (or any basement wall) should protect the walls from both soil and liquid moisture.
Substrate Preparation (Crucial for optimal protection):
- Clean the basement wall and footing surfaces thoroughly to ensure they are debris-free and smooth.
- Check the manufacturer’s literature for temperature limitations before applying the concrete wall waterproofing membrane.
- Only apply membranes on fully cured concrete, as escaping vapor from uncured concrete can prevent the waterproofing material from bonding.
- Waterproofing products do not inherently cover large voids; therefore, use a quality product like BBGF (Blue Barrier Gap Filler) to seal around joints and patch cracks and breaks in the walls.
- BBGF (Blue Barrier Gap Filler): An easy-to-apply, STPE technology-based structural adhesive and detail sealant for filling substrate imperfections and bonding different materials. It’s environmentally friendly, provides superior adhesion, and has a Class A surface burning rating for added fire protection.
Waterproofing Application (General Guidelines):
- Apply waterproofing systems to all basement walls with earth on the exterior and usable space on the interior.
- Extend waterproofing at least 12 inches onto intersecting walls for added effectiveness.
- For wet sites, continue waterproofing on other walls to prevent moisture flow through the keyway, along the footing, and into occupied areas.
- Workers must avoid walking across exposed membranes on footings, decks, or other horizontal surfaces, as this can compromise the waterproofing system.
- Once applied, the waterproofing wall system needs a drainage mat or insulation to protect it during backfill operations.
Polyguard’s Residential Basement Wall Waterproofing Solutions
Polyguard’s Residential Solutions division offers superior products to protect against moisture and air infiltration, contributing significantly to a home’s health, safety, and long-term integrity and value. Their residential line includes two types of basement waterproofing systems: liquid and membrane.
- Home Stretch™ Liquid Waterproofing:
- Application: Can be used on below-grade CMU, poured concrete, precast concrete, and other vertical foundation surfaces exposed to hydrostatic pressure.
- Recommended System: For complete foundation wall waterproofing, Polyguard Residential suggests using Home Stretch™ Liquid Waterproofing in conjunction with BBGF (Blue Barrier Gap Filler), Drain Board, Totalflow T-Outlet, and Totalflow End Outlet Channel System.
- WM40 for ICF Waterproofing:
- Design: Specifically engineered for insulated concrete form (ICF) walls, but also usable on CMU and poured concrete foundation walls. It offers an excellent solution for exterior basement wall waterproofing.
- Material: A self-adhering, 40 mils thick sheet waterproofing membrane made of flexible, strong high-density polyethylene (HDPE) bonded to a rubberized asphalt waterproofing composite. It’s straightforward and quick to install.
- Maximizing Effectiveness: Maximize WM40’s effectiveness by combining it with BBGF (Blue Barrier Gap Filler), Detail Tape, Liquid Waterproofing, Water Based Liquid Adhesive, Drain Board, and Quick Grip.
Polyguard’s Commercial Basement Wall Waterproofing Systems
Polyguard’s commercial basement waterproofing solutions include membranes for both post-applied and pre-applied applications, encompassing both sheet and fluid-applied products. These products are designed for severe conditions, protecting concrete basement walls from water and contaminant infiltration due to concrete imperfections.
- Polyguard Basement Sheet Membranes:
- Blindside Membrane (73 mils): Flexible, puncture-resistant membrane for spaces where soil retention doesn’t allow access to the positive side. Applied vertically before concrete pouring. Curing concrete forms a mechanical bond with the membrane. Can also be installed horizontally over prepared sub-bases.
- 650 Membrane (60-mil): Flexible, strong, self-adhesive waterproofing membrane/vapor retarder that prevents vapor and water transmissions through poured concrete basement walls, ICF, wood, and CMU. Suitable for vertical/secure wall and horizontal/split slab applications for critical waterproofing projects. Available in wide (up to 48 inches) and narrow widths for various applications.
- 650 PRM Puncture-Resistant Membrane (65-mil): A strong, self-healing, post-concrete pour sheet waterproofing/vapor retarder membrane. Features a double-thick, cross-laminated polyethylene backing laminated to a heavy layer of rubberized asphalt compound, sticking tightly and permanently to concrete. Forms a continuous barrier to vapor and water entry. Can be used on exterior vertical sides of concrete basement walls and related applications, often eliminating the need for a separate protection course before backfilling. Also applicable horizontally on plywood decks, parking garages, and plaza decks.
- Below-Grade Fluid-Applied Waterproofing:
- Stretch Flex Fluid-Applied Waterproofing: A single-component product with patented thermoplastic technology. It’s a cold-applied (-20°F capable) spray product that creates a durable, seamless waterproofing membrane. Bridges substrate shrinkage cracks up to 1/16-inch, minimizing surface breaches and joint problems. Designed for easy application to below-grade exterior waterproofing of concrete, CMU, precast concrete, basement walls, and other structural surfaces on the hydro-positive side.
The Best Way to Waterproof a Basement From the Inside
Polyguard also offers solutions for waterproofing a basement from the inside walls, though specific product names are not detailed in this excerpt.
The Best Way to Waterproof a Basement Floor
Water and vapor can infiltrate basement concrete slabs both externally and internally, leading to flooring damage, compromise of the building envelope, poor indoor air quality, and increased energy bills.
- External Moisture: Sources include poor drainage, plumbing leaks, rain, water below or at the slab’s sides, poor ventilation, and air humidity.
- Internal Moisture: Primarily comes from the amount of water used in the cement during concrete creation, which significantly impacts cure time. Excess moisture in concrete also enlarges space between aggregates, lessening compressive strength and durability.
Managing concrete slab moisture requires adequate installation with proper curing and drying, along with installing a heavy-grade, low-permeance, puncture-resistant floor moisture barrier like the Polyguard Underslab Membrane. These under-slab and above-slab products shield flooring from moisture transmission problems.
Under-Slab Moisture Barriers
- To protect concrete basement flooring from damaging moisture intrusion, apply a non-penetrable, low-permeance, heavy-grade vapor barrier (or retarder) over a prepared sub-base (e.g., compacted mud slab, soil, #57 Stone, or carton forms).
- The Concrete Floor and Slab Construction Guide suggests a minimum vapor retarder thickness of ten mils to withstand puncturing during and after construction.
- ASTM E1745-17 and ASTM E1643 18a provide guidelines for installing, using, and inspecting under concrete slab vapor barriers.
- Underslab Membrane (85-mil): A tough, pre-concrete pour, roll-on waterproofing membrane/vapor barrier that effectively eliminates vapor and water transmission through concrete basement floors to protect floor finishes.
- Horizontal Installation: Typically installed horizontally on top of a sub-base. During concrete pouring, the concrete blends with the nonwoven geotextile fibers, creating a solid mechanical bond and a continuous seal under the concrete slab.
- Temperature: Installation should only occur at temperatures above 24°F (-4°C).
- Vertical Applications: Refer to the Blindside Membrane datasheet guidelines.
- Shotcrete Installations: For shotcrete installations in the water table, contact Polyguard Architectural Technical Services.
Contact Polyguard
For more information on the best way to waterproof a basement, Polyguard professionals are available to answer questions regarding their residential and commercial solutions for interior and exterior basement walls and floors.