Choosing the Right Fit: A Comparison of Mapeguard UM and UM 35

At MAPEI, we pride ourselves on innovation and quality, constantly developing products that push the boundaries of performance and efficiency. Two of our standout offerings in the realm of underlayment membranes are Mapeguard UM and Mapeguard UM 35.

These products are designed to cater to different needs in tile and stone installations, providing solutions for crack suppression, waterproofing and vapor management. In this article, we will delve into the key features, benefits and applications of both outstanding membranes to help you understand their unique strengths and ideal uses.

Why use uncoupling membranes in tile installations in the first place? If your tiles are rigidly bonded to the subfloor, you can get cracking of the tile if there is differential movement of the subfloor and tile. In climates where the humidity changes significantly over the course of a year, you are going to get substantial movement of the subfloor, with little movement of the tile, so with no uncoupling membrane you risk stress buildup between the wooden subfloor and the tile. Like with an earthquake, the stress can be relieved via a crack. Bad news. However, with MAPEI uncoupling membranes, the subfloor can move but the movement does not translate into the tile, so you avoid cracking.

Mapeguard UM: A premium-performance membrane

Mapeguard UM is a top-tier, lightweight, waterproofing and vapor-pressure-equalizing underlayment membrane. It is engineered for both residential and commercial applications, particularly over challenging substrates such as young concrete and single-layer plywood subfloors. This membrane is designed to absorb lateral stress from the substrate, thereby preventing the transmission of these stresses to the tile or stone, which helps maintain exceptional bond integrity.

Key features and benefits

• Crack prevention: Mapeguard UM prevents the transmission of in-plane substrate cracks up to 1/8" (3 mm), ensuring the longevity and durability of the tile installation.
• Versatile use: It is recommended for use with polymer-modified mortars and is approved for use over young (green) concrete and mortar beds, making it ideal for projects with tight timelines.
• Ease of installation: The membrane can be embedded and tiled over immediately, saving time and effort. Its engineered cavity design allows for easy single-pass filling of the surface core with less mortar.
• High performance: With waterproofing and water vapor management capabilities up to 25 lbs. (11.3 kg) MVER and 100% relative humidity (RH), Mapeguard UM offers robust protection against moisture.
• Durability: It supports rolling loads and is approved for radiant-heating applications. The compression resistance of the membrane ensures that it can handle heavy traffic and use.
• User-friendly: The membrane’s light green, translucent color shows mortar coverage, and its reduced “roll memory” and tri-layer construction keep it flat. It is lightweight, easy to handle and cuts easily with a utility knife.

Industry standards and approvals
Mapeguard UM carries the following industry standards and approvals:

• ASTM C627 (Robinson): Rated “Extra Heavy”
• ANSI A118.10: Exceeds standards for waterproofing membrane for thin-set ceramic tile
• ANSI A118.12: Achieves bond strength of 50 psi (0.34 MPa) or greater in 7 days and passes point load resistance after 28 days

Applications
Ideal for residential and commercial floors, both interior and exterior, Mapeguard UM is also suitable as a replacement for cement backer board on plywood or oriented strand board (OSB) floors up to 24" (61 cm) on center joist spacing. The membrane is effective when renovating older floors for addressing existing in-plane cracks. It also isolates stresses beneath the flooring associated with expansion and contraction of substrate materials.

Mapeguard UM 35: Versatility and efficiency

Mapeguard UM 35 is another exceptional product from MAPEI, designed to offer uncoupling, crack isolation, waterproofing and vapor management. Made from high-density polyethylene (HDPE) with a rough surface and polypropylene fabric backing, it is particularly suited for challenging substrates, including young concrete and single-layer plywood subfloors.

Key features and benefits

• Wide applicability: Mapeguard UM 35 is suitable for concrete or wood substrates, making it a versatile choice for various installation environments. It’s also great for tile-over-tile installations and for home renovation projects where you don’t want the expense and dust associated with ripping up old tile.
• Crack isolation: It offers crack isolation up to 1/8" (3 mm), protecting the tile installation from substrate movement.
• Low profile: At a thickness of only 1/8" (3 mm), the membrane provides a slim profile that does not significantly raise the finished floor height.
• Ease of use: The circular-shaped cavities allow for easy troweling, and Mapeguard UM 35’s membrane holds a chalk line, facilitating accurate installation.
• Robust performance: It manages vapor up to 25 lbs. (11.3 kg) in MVER and 100% RH, ensuring excellent waterproofing and vapor management.
• Durability: With excellent mechanical and compression strength, Mapeguard UM 35 can withstand significant loads and traffic.

Industry standards and approvals
Mapeguard UM 35 carries the following industry standards and approvals:

• ANSI A118.12 and A118.10: Meets and exceeds standards for crack isolation and waterproofing
• ASTM C627 (Robinson): Rated “Extra Heavy”

Applications
Ideal for interior floors in residential homes and commercial construction, such as hospitals and hotels, Mapeguard UM 35 is suitable for bathroom floors, providing a reliable waterproof barrier. Mapeguard UM 35 is also suitable as a replacement for cement backer board on plywood or oriented strand board (OSB) floors up to 19.2" (49 cm) on center joist spacing.

How do they compare to each other?

Mapeguard UM and Mapeguard UM 35 offer distinct features and benefits tailored to different installation needs. Mapeguard UM can be installed on the second floor with wood substrates up to 24" (61 cm) on center, boasts a three-layer construction. It is suitable for both interior and exterior applications and can accept a self-leveling underlayment (SLU) on top. Additionally, its transparency allows for easy monitoring of mortar coverage, and it is more rigid when compared with Mapeguard UM 35.

In contrast, Mapeguard UM 35 is designed for installation on second floors with wood substrates up to 19.2" (49 cm) on center. It has a two-layer construction. Unlike Mapeguard UM, it is intended for interior use only and does not accept any SLU on top. Though not as transparent, it is effective in holding a chalk line, which aids in precise installation.

Both Mapeguard UM and Mapeguard UM 35 are designed to provide superior performance and reliability in tile and stone installations. While Mapeguard UM offers premium performance with features like exceptional crack prevention, Mapeguard UM 35 provides versatility and efficiency with its low profile and wide applicability.

“Choosing the right underlayment membrane is crucial for the success of any tile or stone installation,” said Sonya Moste, MAPEI’s Product Manager – Crack-Isolation and Sound-Control Membranes. “Mapeguard UM and Mapeguard UM 35 each offer unique benefits that cater to different project needs. Whether you’re dealing with young concrete, looking for a low-profile solution, or need robust vapor management, MAPEI has you covered.”

By understanding the strengths and differences of each product, installers can make informed decisions that ensure durable, high-quality installations, no matter the substrate challenges they face.