Mapei Mapeguard UM 35 Uncoupling Crack Isolation Membrane 323 Sq Ft Roll (3.3 Ft x 98.5 Ft) For Ceramic Tile And Stone Tile, 1/8 Inch Thick HDPE Waterproofing Flooring Underlayment

Product Features:

• High-performance uncoupling membrane controls substrate cracks up to 1/8″ (3 mm) for reliable tile or stone installations.
• Waterproof and vapor-management layer enables up to 25 lb MVER and 100% relative humidity control via air-channel design.
• Low-profile 1/8″ thickness reduces floor build-up while offering robust support for large-format tile, porcelain, stone, ceramic, and mosaic.
• Extra-heavy commercial rating certified ASTM C627 for heavy traffic use in residential, commercial, hotel, hospital, spa, and gallery settings.
• HDPE honeycomb structure with polypropylene backing enhances mechanical strength, compression resistance, and support for heated, underfloor heating or LVT systems.
• Uniform coverage for direct tile adhesion with built-in fleece backing that improves mortar bonding for ceramic tile, porcelain tile, natural stone, granite, marble, and travertine.
• Semi-transparent surface allows visual inspection of adhesive coverage and accurate placement over drains or penetrations.
• Easy to cut, roll out, and install holds chalk lines, lies flat, quick to trim—ideal for contractors and DIY projects alike.
• Vapor-release channels manage moisture from green concrete or plywood substrates, preventing mold, delamination, and grout cracking.
• Suitable for interior and exterior use approved for balconies, terraces, showers, bathrooms, and steam rooms with proper waterproof tape integration.

Product Description:

Mapeguard UM 35 is a premium HDPE uncoupling, crack-isolation, waterproofing, and vapor-control membrane designed for ceramic tile, porcelain tile, natural stone, and large-format tile installations on challenging substrates. Its honeycomb structure and low-profile design make it ideal for commercial, residential, hospital, hotel, spa, and retail settings.

At just 1/8″ (3 mm) thick, this membrane delivers ASTM-certified extra-heavy duty support, distributing point loads while isolating substrate movement. Its waterproof nature and 25 lb MVER vapor control protect floors from moisture intrusion, even on newly poured concrete or un-cured plywood. The semi-transparent design helps installers ensure complete thin-set adhesive coverage beneath stone tile or mosaic.

Made for efficiency, UM 35 holds chalk lines, lies flat without curling, and cuts easily—streamlining tile installation in kitchens, bathrooms, showers, and terraces. It supports heated floor systems, with perforated channels that evenly distribute heat and allow air and vapor to escape.

With mechanical strength suitable for heavy foot traffic, commercial kitchens, hospital floors, and outdoor balconies, UM 35 is versatile and built to last. It installs easily with standard polymer-modified thin-set mortar (C2) and seals, such as Mapeband Easy, to create a fully waterproof underlayment. When paired with proper grout (e.g., Ultracolor Plus) and adhesives, UM 35 ensures long-term durability, moisture resistance, crack prevention, and freeze-thaw protection.

Mapeguard UM 35 supports tile-over-tile, resilient flooring, and heated-slab installations while providing uncoupling, anti-fracture protection, waterproofing, and vapor management all in one roll. If you're looking for a single product to simplify installation, prevent cracks, and prolong the lifespan of ceramic, porcelain, stone, or marble floors—whether for DIY home use or professional commercial projects—UM 35 is the solution.
This roll covers approximately 323 square feet and meets guidelines for interior, exterior, wet-room, and steam-room applications (check local use approvals). Elevate your next tile flooring or renovation project with Mapei’s high-performance Mapeguard UM 35.