FREQUENTLY ASKED QUESTIONS
Understanding the Product
What is the purpose of DMX Tile Membrane?
DMX Tile Membrane is a specialized underlayment material used in tile installations to separate the tile from the substrate and absorb natural movement and stresses reducing the risk of cracks in the tile.
Why is DMX Tile Membrane superior to competing uncoupling membranes?
DMX Tile Membrane features circular dimples which minimizes risk of air pockets in the thinset. It’s white colour creates a transparency underneath the light which allows you to see your coverage on the fleece side of the membrane. Additionally DMX Tile Membrane exceeds all tests set out by the Tile Council of North America (TCNA).
How thick is DMX Tile Membrane?
3mm
Is DMX Tile Membrane waterproof?
Yes, DMX Tile Membrane is 100% waterproof, and can be safely used in moisture prone areas, such as a bathroom.
Substrate & Surface Preparation
Can uncoupling membranes be installed on any type of substrate?
DMX Tile Membrane can be installed on most concrete, cement backerboard, or plywood substrates, provided they are structurally sound and meet the requirements of the Tile Council of North America (TCNA) and ANSI standards.
What is the maximum crack isolation that DMX Tile Membrane will cover?
DMX Tile Membrane provides crack isolation for in-plane movement up to 3mm (⅛”).
Is a primer or surface preparation required before installation?
Usually not. Just make sure the surface is clean, dry, and free of debris. For porous or dusty substrates, follow the thin-set manufacturer’s prep instructions.
Installation — Getting Started
What thinset is compatible with DMX Tile Membrane?
Modified thinset: ANSI A118.4 & A118.15
What is the recommended trowel size I should use?
¼” x ¼” square notched trowel.
What happens if I install DMX Tile Membrane with a different size/shape trowel?
Using the wrong trowel can lead to poor bonding or uneven installation
What is the smallest tile size that can be installed?
2”x2” tiles
Can I install the tile right after bonding DMX Tile Membrane to the substrate?
Yes, you can start tiling right away – there’s no need to wait for the mortar
beneath the membrane to cure.
What is back buttering, and when do I need to back butter?
Back buttering is the process of spreading a thin coat of mortar on the back of the tile before setting it into the bed of thinset on the substrate. It ensures full mortar coverage, eliminates voids, and improves the bond between tile and substrate. We recommend you back butter tile coverings that are 12” x 12” or larger.
Do I need to leave an expansion joint around the perimeter?
Yes, always leave about a ¼” (6mm) gap around walls, columns, and fixed objects.
This allows for natural movement in the floor and helps prevent cracking over time.
How long should I wait before grouting or walking on the tile?
Allow the thinset to cure for approximately 24 hours before grouting or walking on the surface. Cooler or more humid conditions may require additional time, while rapid-setting mortars can cure faster per manufacturer guidelines.
Performance & Longevity
How long does DMX Tile Membrane last?
DMX Tile Membrane is designed to last the life of the tile assembly.
Can I remove and reuse DMX Tile Membrane if I want to get rid of my tiles?
No. Once installed, DMX Tile Membrane is permanently bonded to the substrate and cannot be reused or installed.
Can I use uncoupling membranes in wet areas, such as showers or bathroom floors?
Yes, absolutely. DMX Tile Membrane, is fully waterproof and ideal for bathroom floors when seams are properly sealed with the include DMX Vapor Band.
Common Installation Mistakes to Avoid
Skipping surface prep
Installing over dusty, oily, or uneven substrates prevents proper adhesion between
thinset and membrane. Always clean, flatten, and dry the surface first.
Using the wrong mortar
Using premixed (mastic) or non-compatible mortar instead of DMX-approved thinset (ANSI 118.4 & 118.15) can lead to bonding failures.
Not filling the membrane cavities completely
Incomplete filling creates weak spots and hollow sounds. Make sure the thinset fully embeds into the fleece and cavities before setting tile.
Incorrect trowel size or technique
Using a trowel that’s too small or holding it at the wrong angle can cause poor coverage. Always use the trowel size recommended by the membrane manufacturer. In this case, we recommend ¼” x ¼” square notched trowel.
No movement or perimeter joints
Skipping expansion gaps at walls or transitions causes stress buildup and tile cracking. Always leave the proper joint spacing.
Walking or grouting too early
Applying weight or grout before the thinset cures (usually ~24 hours) can cause tile shift or debonding.
Poor mortar coverage under large tiles
Large-format tiles need more contact. As we spoke about earlier, for 12”x12” tiles or larger, its key to back-butter to achieve at least 80% coverage (95% in wet areas).
Incorrect trowel size or ignoring substrate deflection or joist spacing
Ensure floor structure meets industry standards – L/360 for ceramic tile and L/720 for natural store – as outlined by the Tile Council of North America (TCNA).
Skipping waterproofing details
Failing to seal seams and edges with the DMX Vapor Band leads to leaks, especially in bathrooms or laundry areas.
Not checking alignment early
Once the thinset begins to cure, there’s no fixing crooked tile without tearing it up. Always check layout and level as you go.
Toll Free: 