The Complete Guide to Buying and Installing a Kerdi Board Waterproof Shower Kit: Everything You Need to Know

Revamping your shower can seem overwhelming, but the Kerdi Board Waterproof Shower Kit makes it a breeze. This kit offers a reliable and straightforward solution for building a watertight and durable shower. Many positive reviews highlight the product's quality and ease of use.

In this guide, we’ll explore the standout features of the Kerdi Board system and provide step-by-step installation tips to help you create a beautiful, lasting shower. Whether you’re a DIY enthusiast or a professional, you’ll find valuable insights to make your next bathroom upgrade a success. Let’s get started!

Understanding Kerdi Board

What is the Kerdi Board?

Kerdi Board is a multifunctional tile substrate and building panel that revolutionizes the way tiled shower assemblies are constructed. It is made of extruded polystyrene foam, making it exceptionally lightweight while providing excellent insulation properties. This core is covered with reinforced, fleece webbing on both sides, ensuring a secure bonding surface for tile.

Key Materials and Construction

Kerdi Board’s core material is extruded polystyrene foam, known for its water-resistant and thermal insulation properties. The foam core is sandwiched between layers of synthetic fleece webbing, which serves two critical purposes: it acts as an anchor for the tile adhesive and reinforces the board’s structure. This construction not only makes Kerdi Board waterproof and vapour-tight but also provides high compressive strength and rigidity. Additionally, the design ensures security against water damage, which is a critical concern for human health and safety.

Comparison with Other Waterproofing Solutions

Traditional waterproofing methods often involve multiple steps, including the application of cement backer boards, waterproofing membranes, liquid waterproofing compounds and additional vapour barriers. In contrast, Kerdi Board integrates these functions into a single product. It simplifies installation by combining the tile substrate and waterproofing layer, reducing installation time and the potential for errors. Additionally, Kerdi Board’s lightweight nature makes it easier to handle and cut compared to heavy cement boards.

Additional Features and Benefits

• Thermal Insulation: The foam core provides excellent thermal insulation, improving the overall energy efficiency of the shower area.
• Ease of Customization: The Kerdi Board can be easily cut to size with a utility knife, allowing for precise adjustments during installation.
• Versatility: Apart from shower assemblies, the Kerdi Board can be used in a variety of applications including countertops, shelves, and other tiled surfaces.
• Environmental Resistance: It is resistant to mould and mildew, ensuring a healthier environment in wet areas.

By integrating these features, Kerdi Board offers a comprehensive solution for modern waterproofing needs in tiled shower installations. Its innovative design simplifies the construction process while ensuring long-lasting performance and reliability.

Key Features of Kerdi Board Waterproof Shower Kit

Waterproof and Vapour-tight

The Kerdi Board is designed to be completely waterproof and vapour-tight. This is achieved through its extruded polystyrene foam core, which prevents water absorption and the synthetic fleece webbing that ensures a secure bond for waterproofing seams and joints. This dual-layer protection is crucial in maintaining a dry and mold-free environment in shower installations. The design also provides easy access to all waterproofing features, ensuring thorough protection.

Lightweight and Easy to Handle

Kerdi Board’s lightweight nature is one of its standout features. Unlike traditional cement backer boards, Kerdi Board panels are easy to transport, cut, and install. This ease of handling reduces the physical strain on installers and speeds up the installation process, making it a preferred choice for both DIY enthusiasts and professionals.

Durability and Stability

Kerdi Board offers excellent durability and stability. Its construction is impact-resistant, providing a strong and stable substrate for tiles. The board’s rigidity ensures that it does not warp or sag over time, maintaining the integrity of the tiled surface. Additionally, the polystyrene core provides thermal insulation, enhancing the overall energy efficiency of the shower area.

Versatility in Applications

Kerdi Board is highly versatile and can be used in a variety of applications beyond shower walls. It is suitable for use in bathtubs, countertops, vanities, shelves, and even building custom features like benches and niches. This versatility makes it an all-in-one solution for various waterproofing needs in residential and commercial settings.

There are numerous instructional videos available that demonstrate the versatility of the Kerdi Board in various applications.

Compatibility with Various Tile Types

Kerdi Board is compatible with a wide range of tile types, including ceramic, porcelain, glass, and natural stone. This flexibility allows homeowners and designers to choose from a variety of aesthetic options without worrying about compatibility issues. The secure bonding surface ensures that tiles adhere properly, reducing the risk of tile failure over time.

Components of the Kit

Kerdi Board Panels

Kerdi Board panels are the foundation of the waterproofing system. These lightweight, rigid foam panels are available in various thicknesses and sizes to suit different project needs. The panels are coated with a waterproof membrane on both sides, making them an ideal substrate for tiles in wet areas. Their ease of cutting and handling simplifies installation, reducing labour time and effort.

Kerdi Membrane and Kerdi-Band

The Kerdi membrane and Kerdi-Band are essential for waterproofing seams, joints, and corners. The Kerdi-Band is a sheet-applied waterproofing membrane that creates a continuous waterproof barrier when installed over Kerdi Board panels. Kerdi-Band is a narrow strip of membrane, is specifically designed to seal joints and connections, preventing any potential water infiltration. Together, these components provide a seamless and watertight enclosure, ensuring comprehensive protection against moisture.

Kerdi Shower Tray and Curb

The shower tray and curb are pre-fabricated components designed to create a sloped shower base and contain water within the shower area. The Kerdi shower tray is available in various sizes and shapes, making it easy to find the right fit for any shower layout. The pre-sloped design ensures proper water drainage towards the Kerdi drain. The Kerdi curb provides a barrier at the shower entrance, preventing water from spilling out while maintaining a sleek, finished look.

Kerdi Drain and Accessories

The Kerdi drain is a crucial component that ensures a watertight connection between the shower base and the plumbing system. It features an integrated bonding flange that connects seamlessly with the Kerdi membrane, providing a reliable waterproof seal. The Kerdi drain kit consists of an ABS or PVC flange with options for either vertical or horizontal outlets. It includes a Kerdi grate assembly available in multiple designs, such as Classic, Contour, Floral, Pure, Curve, and Tileable. The kit offers a wide variety of finishes, including Brushed Stainless Steel (EB), Brushed Nickel (EBT), Brushed Rose Gold (EBRG), Brushed Vintage Gold (EBVG), Brushed Classic Gold (EBCG), Matte White (MBW), Ivory (TSI), Greige (TSBG), Cream (TSC), Bronze (TSOB), Stone Grey (TSSG), Pewter (TSG), Dark Anthracite (TSDA), Matte Black (MGS), Brushed Brass (AMGB), Brushed Copper (AKGB), Stainless Steel (E), Chrome (EP), Oil-Rubbed Bronze (EOB), Nickel (ET), Rose Gold (ERG), Vintage Gold (EVG), Classic Gold (ECG), and Tile (ECS), ensuring a perfect match for various bathroom designs.  Additional accessories, such as mixing valve and pipe seals, as well as inside and outside waterproof corners, are also included to ensure complete waterproofing around plumbing penetrations.. The secure connection provided by the Kerdi drain ensures that users can account for every drop of water, preventing leaks and water damage.

Additional Tools and Materials

To facilitate the installation process, you may require additional tools and materials such as:

• Fasteners and washers: To secure the Kerdi Bard panels.
• Thin-set mortar: For adhering Kerdi-Band strips to cover all seams and joint lines created during the installation of Kerdi Board panels once they are anchored to the walls.
• Preformed corners and edges: For easy installation in tricky areas.
• Installation guides and manuals: Providing detailed instructions and tips for a successful installation.

These components, when used together, create a comprehensive waterproofing system that ensures a durable, leak-free shower installation.

Preparing for Installation

Tools and Materials Needed

Before starting the installation, gather the following tools and materials:

• Tools: Utility knife, trowel, measuring tape, level, notched trowel, mixing bucket, sponge, and drill with mixing paddle.
• Materials: Kerdi Board panels, Kerdi-Band, Kerdi membrane, thin-set mortar, screws and washers, Kerdi-Fix sealant, Kerdi prefabricated curb, Kerdi drain kit, Kerdi grate assembly and waterproofing accessories.

Safety and Security Considerations

Safety should be a priority during the installation process:

• Personal Protective Equipment (PPE): Wear gloves, safety glasses, and a dust mask to protect yourself from debris and dust.
• Workspace Safety: Ensure the workspace is well-ventilated and free of obstacles to prevent accidents. Keep tools and materials organized and within reach.

Site Preparation Tips

Proper site preparation is crucial for a successful installation:

• Remove Existing Materials: Strip down any existing wall coverings, fixtures, and fittings from the shower area. Ensure the surface is clean, dry, and free of any dust or debris.
• Inspect the Structure: Check the walls and floor for any signs of damage or mould. Repair any structural issues before proceeding with the installation.
• Ensure Level and Plumb Walls: Use a level to check that the walls are straight and plumb. Uneven surfaces can affect the installation and performance of the Kerdi Board panels.

Moisture Barrier Installation

If the shower area is prone to moisture, consider installing a moisture barrier:

• Moisture Barrier Application: Apply a moisture barrier over the studs before installing the Kerdi Board. This extra step ensures an added layer of protection against water infiltration.
• Sealing Penetrations: Seal all penetrations, such as pipes and fixtures, with appropriate sealant to prevent water ingress.

Planning and Layout

Proper planning and layout can simplify the installation process:

• Panel Layout: Plan the layout of the Kerdi Board panels to minimize cuts and waste. Measure the shower area and mark the dimensions on the panels before cutting.
• Cutting Panels: Use a utility knife to cut the panels to size. Make sure the cuts are clean and accurate to ensure a proper fit.
• Dry Fit Panels: Before tiling, place the cut panels against the walls to ensure they fit properly. Make sure the panels are anchored securely to the wall using Kerdi screws and washers. Once everything is in place, proceed with tiling.

By thoroughly preparing for the installation, you ensure a smoother, more efficient process and a longer-lasting, waterproof shower assembly.

Step-by-Step Installation Guide

Wall Preparation

1. Clean and Prep the Walls: Ensure the shower walls are clean, dry, and free of any dust or debris. Use a damp cloth to wipe down the surfaces.
2. Check for Structural Soundness: Verify that the wall studs or other structural components are in good condition and can support the Kerdi Board panels.

Cutting and Fitting the Panels

1. Measure the Area: Measure the height and width of each wall section to determine the size of the Kerdi Board panels needed.
2. Cut the Panels: Use a utility knife and a straight edge to cut the panels to the required dimensions. Score the panel with the knife and snap it along the scored line.
3. Dry Fit the Panels: Before tiling, place the cut panels against the walls to ensure they fit properly. Make sure the panels are anchored securely to the wall using Kerdi screws and washers. Once everything is in place, proceed with tiling.

Securing the Panels

1. Fasten with Screws and Washers: Use Kerdi Board screws and washers to secure the panels to the wall studs or framing. Place fasteners approximately every 12 inches.
2. Apply Thin-Set Mortar: After installing Kerdi boards, fill the joint seam lines (gaps naturally formed on the wall surface) with Schluter SET™, ALL-SET™, FAST-SET™, or an unmodified thin-set mortar. Mix the mortar according to the manufacturer's instructions. Apply an even layer using a notched Kerdi trowel to fill gaps, ensuring full coverage between Kerdi board joint lines. 

Waterproofing Seams and Joints

1. Apply Kerdi-Band: Cut Kerdi-Band strips to cover all seams and joint lines. Use thin-set mortar to adhere the band to the Kerdi Board naturally formed gaps, ensuring an overlap of at least 2 inches. Following these steps will guarantee the membrane fleece is securely bonded, achieving watertight system performance and effectively insulating against moisture.
   
   
2. Embed Kerdi-Band: Press the Kerdi-Band into the mortar with a flat trowel, ensuring no air bubbles are trapped and the band is fully embedded.

Installing the Shower Tray and Curb

1. Prepare the Floor: Ensure the floor is level and clean. Adjust the subfloor if necessary to accommodate the shower tray.
2. Place the Shower Tray: Cut the tray to fit the shower area if needed. Apply thin-set mortar to the floor and set the tray in place, pressing firmly to ensure full coverage.
3. Install the Curb: Apply mortar to the bottom of the curb and set it in place at the shower entrance. Ensure it is level and aligned with the tray.

Drain Installation

1. Position the Drain: Place the Kerdi drain flange in the pre-cut hole in the shower tray. Ensure it is properly aligned and seated.
2. Secure the Drain: Apply thin-set mortar to the flange and press it into place. Ensure a watertight seal by embedding the Kerdi membrane around the drain flange, overlapping the tray.

By following these detailed steps, you can ensure a successful installation of the Kerdi Board Waterproof Shower Kit, resulting in a durable and watertight shower assembly.

For extra help, you can also check this video from Schuter:

Tips for a Successful Installation

Common Mistakes to Avoid

• Inadequate Surface Preparation: Ensure all surfaces are clean, dry, and free of debris before installation. Any contaminants can prevent proper adhesion.
• Incorrect Mortar Application: Apply thin-set mortar evenly using a notched trowel. Avoid using too little or too much mortar, as this can compromise adhesion  and the waterproofing integrity.
• Ignoring Manufacturer Instructions: Always follow Schluter's guidelines for Kerdi Board installation to ensure proper setup and performance.

Ensuring Proper Alignment and Leveling

• Use a Level and Straight Edge: Continuously check the alignment and level of Kerdi Board panels during installation. Proper alignment ensures the tiles will be straight and level, preventing future issues.
• Dry Fit Panels: Before tile application, dry fit the Kerdi boards to ensure they align correctly and make any necessary adjustments. This step helps identify potential issues before tiling.

Tips for Working with Thin-Set Mortar

• Mixing Consistency: Mix the mortar to the recommended consistency—smooth and lump-free. Improperly mixed mortar can compromise the bond between the Kerdi Board and tiles.
• Application Technique: Apply the mortar with the flat side of the trowel first to ensure full coverage, then use the notched side to create ridges. This technique enhances the bond strength.
• Work in Small Sections: Apply the mortar in small sections to prevent drying before the tiles are secured. This method ensures a strong, lasting bond.

Securing Panels

• Fasteners and Washers: Use the recommended screws and washers to properly secure the Kerdi Board panels. Once the boards are installed, the areas where screws have been used to secure them to the wall must be overlapped with Kerdi-Band to maintain waterproofing integrity. 
• Proper Spacing: Follow the manufacturer’s guidelines for spacing fasteners. Evenly-spaced fasteners ensure that the board is securely attached and maintains its integrity.

Sealing Seams and Joints

• Overlap Kerdi-Band: When applying Kerdi-Band over seams and joints, ensure it overlaps by at least 2 inches to create a continuous waterproof barrier.
• Smooth Out Air Bubbles: Use a flat trowel or drywall knife to smooth out any air bubbles under the Kerdi-Band. Air bubbles can compromise the waterproofing if left untreated.

Finishing Touches and Videos

• Edge Protection: Use Schluter edge profiles during tile installation to protect the edges. These profiles not only provide a clean, finished look but also enhance durability. Final Inspection: After installation, inspect all seams, joints, and edges to ensure everything is properly sealed and secure. Address any issues immediately to prevent future problems.

FAQs and Additional Information about the Kerdi Board Waterproof Shower Kit

How long does it take to install a Kerdi Board shower?

The installation time for a Kerdi Board shower can vary depending on the size of the shower and the installer’s experience. On average, a standard-sized shower can be completed within a few days. This includes time for preparing the site, cutting and fitting the panels, securing them, waterproofing seams, and allowing for proper curing of adhesives and mortar.

Can Kerdi Board be used in steam showers?

Yes, the Kerdi Board is suitable for steam showers. Its vapour-tight properties make it an ideal choice for steam shower installations, ensuring that moisture and steam do not penetrate the walls. This helps maintain the integrity of the shower structure and prevents issues related to moisture buildups, such as mould and mildew.

What type of tiles can be used with the Kerdi Board?

Kerdi Board is compatible with a wide range of tile types, including ceramic, porcelain, glass, and natural stone tiles. Its reinforced fleece webbing provides a secure bonding surface for tile adhesives, ensuring a strong and durable bond regardless of the tile material. This versatility allows for a variety of design options to suit any bathroom decor.

How do I clean and maintain my Kerdi Board shower?

Cleaning and maintaining a Kerdi Board shower is straightforward. Regular cleaning with mild, non-abrasive cleaners helps keep the tiles and grout looking new. Avoid using harsh chemicals or abrasive tools that could damage the tile surface or grout lines. For long-term maintenance, periodically inspect the shower for any signs of wear or damage, and address any issues promptly to prevent water ingress.

Can I install the Kerdi Board myself, or do I need a professional?

Kerdi Board is designed to be user-friendly, making it accessible for both DIY enthusiasts and professionals. If you have basic handyman skills and follow the installation instructions carefully, you can successfully install the Kerdi Board yourself. However, for complex installations or if you are unsure about any part of the process, hiring a professional can ensure a flawless and worry-free installation.

What is the warranty on Kerdi Board products?

Kerdi Board products come with a manufacturer's warranty. Subject to the conditions and limitations as stated hereinafter, Schluter®-Systems* warrants that Schluter®-KERDI-BOARD (the “Product”) will be free from all manufacturing defects and will not rot, deteriorate or break down under normal use for a period of ten (10) years. Proper installation and adherence to maintenance guidelines are essential for extending the life of your shower.

Are there any specific adhesives recommended for use with Kerdi Board?

We recommend using Schluter’s thin-set mortars, such as Schluter SET™, ALL-SET™, and FAST-SET™, or an unmodified thin-set mortar for tile applications. These products are ideal for bonding the Kerdi Tray to the substrate and setting tiles. Schluter mortar adhesive is specially formulated to work seamlessly with Schluter Systems products, ensuring optimal performance and a strong, reliable bond.

Can Kerdi Board be used in areas other than showers?

Absolutely! Kerdi Board is highly versatile and can be used in various applications, including countertops, bathtub surrounds, vanities, shelves, and even custom furniture pieces. Its waterproof and stable properties make it an excellent choice for any area that requires a durable, moisture-resistant substrate.

How does the Kerdi Board compare to traditional cement backer boards?

Kerdi Board offers several advantages over traditional cement backer boards. It is significantly lighter, making it easier to handle and install. Additionally, it combines the tile substrate and waterproofing layer into one product, streamlining the installation process. Kerdi Board also provides better thermal insulation and is less prone to mould and mildew growth due to its waterproof and vapour-tight properties.

What are the main benefits of using a Kerdi Board Waterproof Shower Kit?

The main benefits of using a Kerdi Board Waterproof Shower Kit include:

• Comprehensive waterproofing and vapour-tight protection.
• Lightweight and easy-to-handle materials.
• Versatility in various applications.
• The simplified installation process reduces labour time and potential errors.
• Compatibility with a wide range of tile types and designs.
• Durability and long-term reliability, ensure a secure and lasting shower installation.