Water has a way of sneaking into places it shouldn’t. When it comes to buildings, that’s a problem. Leaks and moisture can lead to all sorts of headaches, from mold and mildew to serious, costly structural issues. That’s why waterproofing membranes are a must-have in wet-area construction projects, where water exposure is an obvious concern.
In this guide, we’ll walk through the most common types of waterproofing membranes, how they’re used, and what to consider when choosing one for your home renovation project.
What Are Waterproofing Membranes?
Waterproofing membranes are protective barrier systems designed to stop water damage by blocking or controlling water movement where it doesn’t belong. They’re typically applied to surfaces like roofs, walls, foundations, and floors to protect building assemblies and help structures last longer.
Whether you're working on a home remodeling project or addressing repairs, waterproofing membranes provide a reliable solution for moisture control and water protection (when properly selected for the specific installation environment).
Where Are Waterproofing Membranes Used?
Wet Areas
Wet areas such as showers, bathrooms, laundry rooms, and wet rooms require special attention. Water can seep through tile grout, floor joints, and transitions, so using a shower waterproofing membrane beneath tile assemblies helps create a continuous watertight barrier that protects the substrate.
Outdoor Spaces
Terraces, patios, balconies, and planters are exposed to harsh outdoor conditions. Installing a waterproof membrane underneath these surfaces helps protect the structure from rain, snow, and temperature fluctuations, preventing water damage and freeze-thaw deterioration.
Basements
Being underground, basements are naturally prone to moisture intrusion and hydrostatic pressure. Investing in a basement waterproofing membrane applied to foundation walls or beneath concrete slabs is one of the most effective ways to keep these spaces dry and prevent long-term moisture-related issues. In many cases, proper drainage, exterior waterproofing, and hydrostatic pressure management are also required to keep these spaces dry and prevent long-term moisture-related issues.
Different Types of Waterproofing Membranes
Now that we understand the importance of waterproofing, let’s explore the different options available. The right choice depends on your specific project requirements, substrate conditions, and installation method. Waterproofing membranes generally fall into two main categories: sheet membranes and liquid-applied membranes. Within each, there are important distinctions worth understanding.
Waterproofing Sheet Membranes
Sheet membranes come in rolls and are physically cut, fitted, and bonded to the substrate. They provide consistent thickness and reliable coverage across large areas.
POLYETHYLENE SHEET MEMBRANES
These are the most widely used waterproofing membranes for tile and stone installations. Made from a polyethylene core with non-woven polypropylene fleece layers bonded to both sides, they are installed by embedding the membrane in thin-set mortar. The fleece layers create a strong mechanical bond with the mortar on both the substrate side and the tile side. Polyethylene sheet membranes are commonly used in showers, bathrooms, steam rooms, and other wet areas. They also serve as vapor retarders, making them suitable for moisture-sensitive environments. Popular examples include the Ardex TLT 717, Mapei Mapeguard WP 200, Kobau Flex SD60, PROVA-MAT, IB Tools, Schluter Kerdi, and Laticrete HYDRO BAN Sheet.
PEEL-AND-STICK MEMBRANES
These self-adhering membranes feature a pressure-sensitive adhesive backing that eliminates the need for thin-set mortar during membrane installation. They are easy to install and well-suited for detailed work, smaller projects, and areas requiring precise application. Peel-and-stick membranes can also provide additional benefits such as crack isolation and sound reduction. The Mapei Mapeguard 2 is a well-known example of this type.
UNCOUPLING AND CRACK-ISOLATION MEMBRANES
While not exclusively waterproofing products, many uncoupling membranes also provide waterproofing and vapor-retarding properties. These membranes feature a structured design — often with a grid or bone-shaped pattern — that absorbs lateral stress between the substrate and the tile, preventing cracks from transferring through to the finished surface. They are ideal for installations over substrates prone to movement, such as concrete slabs or wood subfloors. Examples include the Ardex FLEXBONE UI 740, RedGard Uncoupling Membrane, and Kiesel Uncoupling Membrane.
Liquid Applied Waterproofing Membranes
Liquid-applied membranes are brushed, rolled, or troweled directly onto the substrate, where they cure to form a seamless, continuous waterproof barrier. They are especially effective at sealing around drains, corners, pipes, and other complex transitions where sheet membranes require additional detailing.
LIQUID RUBBER MEMBRANES
These single-component, ready-to-use liquid membranes cure into a flexible, rubber-like waterproof layer that bonds tightly to the substrate. They are among the most popular choices for shower and bathroom waterproofing because they are easy to apply and create a seamless barrier without joints or seams. Many liquid rubber membranes also provide crack-isolation properties. Tile can typically be installed directly over the cured membrane after a relatively short drying period. Well-known products in this category include Laticrete HYDRO BAN (liquid), Laticrete HYDRO BAN XP, Mapei Mapelastic AquaDefense, Custom Building Products RedGard (liquid), and KobauFlex KFA.
CEMENTITIOUS WATERPROOFING COMPOUNDS
These membranes are composed of cement, polymers, and other additives that are mixed and applied as a coating. They bond well to concrete and masonry surfaces and cure to form a durable, waterproof layer. Some are two-component systems (a liquid polymer mixed with a powder), while others are single-component and premixed. Cementitious compounds are commonly used in bathrooms, kitchens, and areas where a strong bond to cementitious substrates is important. They are often paired with reinforcing fabric at corners, joints, and transitions for enhanced protection. Examples include Ardex 8+9, Ardex S 1-K, and Laticrete HYDRO BAN Cementitious.
Waterproofing Accessories
A complete waterproofing system involves more than just the membrane itself. Accessories such as seam tapes, preformed corners (inside and outside), pipe seals, valve collars, drain flashings, and reinforcing fabrics are essential for sealing joints, transitions, and penetrations — the areas most vulnerable to water intrusion. These components are designed to work with specific membrane systems and should always be selected according to the manufacturer’s recommendations.
Best Products Available at GTD Supply
We carry a wide range of proven waterproofing solutions suitable for residential and commercial applications, including the following:
Sheet Membranes
ARDEX TLT 717
A high-quality polyethylene waterproofing and vapor-retarding membrane with durable nonwoven polypropylene fabric on both sides. Its low permeability rating makes it suitable for both standard showers and commercial steam shower applications.
MAPEI MAPEGUARD WP 200
An uncoupling, crack-isolation, and waterproofing membrane designed for use under ceramic tile and stone. At just 0.02” thick, it adds minimal height to the floor assembly.
KOBAU FLEX SD60
A 25 mil thick polyethylene waterproofing membrane with dual fleece bonding layers, providing waterproofing, vapor retarding, and crack-prevention properties. A cost-effective option for residential and commercial tile installations.
MAPEI MAPEGUARD 2
A lightweight, peel-and-stick membrane that delivers crack isolation, waterproofing, and sound reduction in a single product. Its self-adhering design allows for fast, mortar-free membrane installation.
Liquid-Applied Membranes
LATICRETE HYDRO BAN (LIQUID)
A single-component, self-curing liquid rubber waterproofing and crack-isolation membrane. HYDRO BAN forms a flexible, seamless barrier without the need for reinforcing fabric in the field, coves, or corners. It bonds directly to a wide variety of substrates, provides anti-fracture protection over non-structural cracks up to 1/8”, and allows for rapid installation with flood testing in as little as 2 hours at 70°F (21°C).
MAPEI MAPELASTIC AQUADEFENSE
A premixed, quick-drying liquid-rubber waterproofing and crack-isolation membrane engineered for installation under ceramic tile and stone in residential and commercial applications. AquaDefense dries quickly and can receive tile in approximately 30 to 50 minutes, with flood testing permitted after 12 hours. It provides a thin, continuous watertight barrier and exceeds ANSI A118.10 and A118.12 standards.
CUSTOM BUILDING PRODUCTS REDGARD (LIQUID)
A trusted, quick-drying liquid rubber waterproofing membrane suitable for interior and exterior tile and stone applications. RedGard creates a continuous waterproof barrier with outstanding adhesion and is elastic enough to bridge non-structural cracks.
ARDEX 8+9
A two-component, cement-based rapid waterproofing and crack-isolation compound. When mixed, it forms a highly flexible waterproof membrane suitable for use under tile in showers, bathrooms, kitchens, and balconies. Often paired with Ardex SK Mesh reinforcing fabric at transitions and corners.
Accessories
- Seam Tapes: Ardex TLT 709/710/711, Profilitec Foiltec Strip, Kobau Membrane Band, Superseal Seam Cloth, Schluter KERDI-BAND, and Kiesel Sealing Tape.
- Preformed Corners: Ardex TLT 704/705 (inside/outside), Kobau Inside/Outside Corners, Schluter KERDI Corners, Prova Inside Corners, and Kiesel Corners.
- Pipe Seals & Valve Collars: Ardex TLT 713 Pipe Collar, Ardex TLT 714 Valve Seal.
- Reinforcing Fabrics: Ardex SK Mesh, Ardex SK-25, Laticrete Anti-Fracture Fabric.
- Waterproofing Kits: Ardex TLT-715 Waterproofing Kit (corners, pipe seal, valve seal), Ardex TUBKIT Bathtub Waterproofing Kit.
How to Choose the Right Waterproofing Membrane?
There’s no one-size-fits-all solution when it comes to waterproofing membranes. Consider the following factors when selecting the right product:
- Substrate Type: Different membranes bond best to specific surfaces such as concrete, wood, or metal.
- Interior vs. Exterior Use: Exterior applications require membranes that resist UV exposure and can withstand temperature changes.
- Above vs. Below Ground: Below-ground installations may need more robust systems which are capable of handling hydrostatic pressure.
- Installation Complexity: Some membranes require professional installation, while others are more DIY-friendly.
Consulting with a knowledgeable supplier, such as GTDSupply, can help ensure you select the correct waterproofing solution for your project.
Best Practices for Sheet Membrane Installation
Proper installation is just as important as selecting the right product. Follow these best practices to ensure a successful installation:
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- Prepare the surface properly. Clean the area thoroughly, removing dust, oil, and loose materials. Repair any cracks or damage before applying the membrane.
- Prime if required. Some membranes require a primer for proper adhesion. Always follow the manufacturer’s instructions and don't skip this step if it is recommended.
- Measure and cut sheet membranes accurately. Allow for seam overlaps exactly as specified by the manufacturer. Overlap requirements vary by product.
- Apply from bottom to top on vertical surfaces. Start at the lowest point and work upward. This creates shingle-like overlaps that naturally shed water.
- Eliminate air pockets. Use a roller or flat edge to press sheet membranes firmly into place, working from the center outward to remove any trapped air.
- Seal all seams and edges. Corners, joints, and pipe penetrations are common failure points and must be sealed with approved accessories. Note: Use the manufacturer's recommended seam tape or sealant to ensure these vulnerable areas are fully waterproof.
- Test before covering. In wet area applications, such as showers and bathrooms, perform a flood test before installing tile or other finishes, following the membrane manufacturer’s required cure time and testing duration. Block the drain and fill the area with water, monitoring for leaks as specified in the product’s technical sheet.
How to Keep Sheet Membranes in Good Shape
A correctly installed waterproofing membrane can provide long-term performance. Actual service life varies by product type, installation quality, exposure conditions, and maintenance practices. Follow these post-installation best practices to help protect your system and prevent premature failure:
- Avoid puncturing sheet membranes during installation and finishing work. Keep sharp tools, fasteners, and heavy equipment away from installed membranes. When walking on exposed membranes, wear soft-soled shoes and avoid dragging materials across the surface. Even small punctures or tears can compromise the waterproof barrier.
- For exposed or accessible membranes, schedule regular visual inspections. Periodic checks help catch issues early before they lead to water damage. Look for signs such as tears, blisters, bubbles, loose edges, or areas where the membrane has separated from the substrate.
- Address any signs of water damage immediately. If moisture appears where it should not, investigate the source right away. Prompt repairs can often be localized and prevent water from spreading into surrounding materials, helping avoid costly structural damage.
- Keep warranty documentation and leftover materials for future repairs. Retaining product labels, warranty information, and extra material makes future repairs or touch-ups much easier and ensures compatibility if maintenance is required later.
Final Thoughts
Waterproofing membranes may not be the most visible or exciting part of your renovation, but they are among the most important. These hidden layers protect your investment by preventing costly water intrusion, mold growth, and long-term structural damage. Since different waterproofing membranes are designed for different applications, choosing the right system for your specific project is essential.
Whether you’re completing a bathroom remodel, finishing a basement, protecting a roof, or weatherproofing an outdoor space, proper waterproofing forms the foundation of a successful renovation. Careful product selection, correct installation, and ongoing maintenance all work together to deliver durable, long-lasting results.
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