Movement in the substrate can happen for a variety of reasons and could cause cracking in your tiles. However, by using KERDI membrane as an uncoupling membrane, any movement in the substrate will not impact on the tiles. It also provides a waterproof barrier and is suitable for use in bathrooms and wet rooms.
Full Answer
What is an uncoupling membrane?
Does thinset stick to ditra?
What is the difference between DITRA and KERDI?
In this application, the Kerdi membrane is lightweight so a small notch trowel is essential. The Ditra and Ditra XL are a larger (heavier) material which requires more mortar for installation. This is why the larger notch trowel is recommended.
Can I use uncoupling membrane mortar with KERDI?
TEC® Skill Set™ Uncoupling Mortar is a dry set mortar made for use with Schluter®-DITRA uncoupling membrane and Schluter®-KERDI waterproofing membrane.
What is the best uncoupling membrane?
Although uncoupling membranes are easily available and it seems like they would prevent cracked tile floors we can't and shouldn't assume that they will. CIS membranes are still the top performers in the tile world.
Is KERDI a crack isolation membrane?
Schluter®-KERDI is a pliable, sheet-applied, bonded waterproof membrane and vapor retarder with limited crack-bridging capabilities.
Why can't you use modified thinset on KERDI?
Modified thinset mortars aren't recommended for use with Kerdi because they must dry out to gain strength, whereas the membrane inhibits drying, which can lead to unpredictable results. For example, if a shower is used before the mortar has cured properly, leaks and polymer leaching can occur.
Why does KERDI require unmodified thinset?
Portland cement-based unmodified thin-set mortars are dependent on the presence of moisture for hydration in order to gain strength. Since KERDI is impervious, it does not deprive the mortar of its moisture. This allows the cement to properly hydrate, resulting in a strong, dense bond coat.
What is the difference between uncoupling and decoupling membrane?
Decoupling membranes are designed to neutralize tensions between the substrate and the tiles. The uncoupling membrane helps to prevent stress cracks from transferring through to the finished tiled surface.
Do I need uncoupling membrane for tile?
As substrates will expand and contract due to changes in temperature and moisture levels, an uncoupling membrane is perfect for allowing the surfaces to move independently preventing stress on the tiles which can cause cracking or even debonding.
Is tile uncoupling membrane necessary?
Uncoupling membranes in the tile assembly are fast becoming an essential and affordable part of the tile installation process. Uncoupling is a method that can be used with all of the most common joist spans used in residential construction.
Is uncoupling membrane better than cement board?
Uncoupling mats provide crack isolation protection because they allow lateral substrate movement. Backer boards are made of concrete and fiberglass mesh, and must screwed into the subfloor to secure it. Because it's screwed down, it can't provide crack protection like uncoupling mats.
Do you need cement board with Kerdi membrane?
Yes,Kerdi can be installed on drywall or cement board. However if installed on drywall it is only protecting one side. The back side of the drywall fails and it is just as bad or worse than if it had an issue on the tile side. All shower/tub areas should have concrete board (I prefer hardiboard).
Does tile go directly on KERDI-BOARD?
For most installations of KERDI-BOARD, tile can be installed right away. Exceptions include curved wall areas and non-bearing partition wall systems. In these applications, the tiles can be installed once the bonding materials have cured sufficiently to stabilize the KERDI-BOARD assembly.
What kind of mortar do you use with KERDI?
Schluter SET™, ALL-SET™, FAST-SET™ or an unmodified thin-set mortar must be used to construct all KERDI seams to ensure watertightperformance of the system.
Is Mapei uncoupling membrane mortar unmodified?
MAPEI's Uncoupling Membrane Mortar does not contain polymer and is considered non-modified.
Is uncoupling mortar unmodified?
Uncoupling Membrane Mortar is an unmodified, dry set, medium bed mortar that was created for use with uncoupling membrane and waterproofing membrane.
Can I use modified thinset with Schluter?
Can I use other manufacturers' modified thin-set mortars to install tile over Schluter boards and membranes? No. Our position on the use of other manufacturers' thin-set mortars within our systems in general has not changed.
The Difference Between Uncoupling Mats and Backer Board
For many centuries, tile has been installed on reinforced mortar beds that have been free to move independent of the subfloor. This was done with a weakly bonded plane situated between the reinforced mortar bed and the subfloor. If the subfloor moves and cracks, it won’t be spread to the underlayment or through to the …
UK Tiling Forum - When do I use a Decoupling Membrane??
Hi all :thumbsup: Having never used this product I just want to get things straight. 1. I've just been out to 2 quotes and both of them are using natural stone onto concrete screed. One has piped heating under the screed and the other hasn't. Is it best to quote membrane for both of these...
What is an uncoupling membrane?
An uncoupling membrane provides a break between two rigid surfaces. In other words, it allows both surfaces to move independently. When you bond tile directly to a rigid surface, say concrete or cbu, or even plywood, the thing between them must have enough flexibility to keep the stresses low enough so that the bond can keep them attached. When that bond between two rigid surfaces is thinset, that thinset must have some flexibility, and that is why you may need a modified thinset to reliably hold things together when bonding directly. Ditra can also be used and acts as a thinset modifier.
Does thinset stick to ditra?
While the membrane’s fleece IS bonded to the substrate, thinset does NOT stick to Ditra, and there are voids between the pillars that hold the tile up which means that if a lateral stress is applied, the whole tile and thinset layer can move totally independently of the subfloor or slab only restricted by the flexibility of the Ditra membrane. The membrane can move MUCH further than any difference in the expansion coefficient of the tile and any rigid substrate. Therefore, while the bond to a tile is less strong than that when you might use a modified, that bond is made under ideal conditions (the water is trapped, and can allow the cement curing to complete growing the crystals that actually create the bond to their maximum capability) and the thinset and tile can move without putting any stress on the tile-thinset bond. Plus, when you use an unmodified thinset to bond things, the cure occurs in a reliable timeframe. I was in a class this week, and the instructor talked about one test they did using a glass tile over a waterproof membrane (Ditra). You could see the thinset through the tile, and could tell the difference between ‘wet’ uncured thinset and cured. They watched that tile for 90-days seeing that grey spot shrink, until it finally was entirely dry. This is the reason Schluter doesn’t want you to use a modified thinset over Ditra…until that modified thinset has fully cured, it is still soft and being conservative, they do not want your installation to fail…a dryset (unmodified) thinset has many times more strength than the stresses that can be applied through the flexible Ditra uncoupling membrane. Think of the Ditra as the modifier in your thinset, and it can stretch MUCH more than a modified between two rigid surfaces AND, it reaches that strength in a know, short timeframe. IOW, if you understand how this works, your trepidation about modified goes away when told to use an unmodified when using Ditra.
What Is an Uncoupling Membrane?
Temperature and moisture changes cause substrates and tiles to expand and contract at different rates and an uncoupling membrane is used when you don’t want to bond the tiles directly to the substrate.
When Should You Use an Uncoupling Membrane?
An uncoupling membrane is used most often when laying tile over concrete, but it can also be used:
Schluter-DITRA Uncoupling Membranes
Schluter-DITRA membranes uncouple tiles from substrates, provide waterproofing, and add to the durability of the installation by distributing heavy loads. They also prevent moisture buildup via built-in channels, protecting tile from damage.
Schluter-DITRA Membranes from Centura Tools
In combination with the Schluter-DITRA-HEAT-E-HK heating cables, this membrane is used for interior floor warming applications. The heating cables snap into the membrane without the need for clips or fasteners.
Visit Centura Tools for Tile Tools and Equipment
If you need versatile, high-quality tools for your tiling project, look no further than Centura Tools. We supply the best products from the top tiling brands around the world, to ensure you have what you need to complete your work professionally and safely.
What is Kerdi Membrane?
Schluter Kerdi membrane is a flexible, sheet applied waterproofing and vapor-retarder membrane that is typically applied to shower walls, bathtub surrounds, and other tile applications where moisture will be present. Kerdi Membrane is designed for direct tile application.
How to install Kerdi membrane?
To install Kerdi Membrane, start by applying Schulter ALL-SET mortar (or similar) to your cement board substrate using a 1/4” x 3/16” V-Notch Trowel. Cut the Kerdi membrane to size using a utility knife or scissors. Press the Kerdi Membrane into the Thinset Mortar with firm, even pressure to achieve full mortar coverage. Remove any excess thinset mortar from underneath the membrane using the flat side of a trowel or a putty-knife.
How to remove air bubbles from Kerdi membrane?
Remove any excess mortar or air bubbles from beneath the Kerdi Membrane by “sweeping” them to the side with the flat side of the trowel.
How to embed a Kerdi membrane into a thinset?
Once a sufficient amount of thinset mortar has been applied to the substrate, press the Kerdi Membrane into the mortar, fully embedding the membrane into the thinset.
What substrate should I use for Kerdi membrane?
Before Kerdi membrane can be installed, you need to have a properly prepared substrate. Typically, cement board is the best substrate for Kerdi Membrane installation on walls.
Can Kerdi membrane be used on walls?
Continue to apply Kerdi Membrane in this manner for all walls that require waterproofing.
What is an uncoupling membrane?
An uncoupling membrane provides a break between two rigid surfaces. In other words, it allows both surfaces to move independently. When you bond tile directly to a rigid surface, say concrete or cbu, or even plywood, the thing between them must have enough flexibility to keep the stresses low enough so that the bond can keep them attached. When that bond between two rigid surfaces is thinset, that thinset must have some flexibility, and that is why you may need a modified thinset to reliably hold things together when bonding directly. Ditra can also be used and acts as a thinset modifier.
Does thinset stick to ditra?
While the membrane’s fleece IS bonded to the substrate, thinset does NOT stick to Ditra, and there are voids between the pillars that hold the tile up which means that if a lateral stress is applied, the whole tile and thinset layer can move totally independently of the subfloor or slab only restricted by the flexibility of the Ditra membrane. The membrane can move MUCH further than any difference in the expansion coefficient of the tile and any rigid substrate. Therefore, while the bond to a tile is less strong than that when you might use a modified, that bond is made under ideal conditions (the water is trapped, and can allow the cement curing to complete growing the crystals that actually create the bond to their maximum capability) and the thinset and tile can move without putting any stress on the tile-thinset bond. Plus, when you use an unmodified thinset to bond things, the cure occurs in a reliable timeframe. I was in a class this week, and the instructor talked about one test they did using a glass tile over a waterproof membrane (Ditra). You could see the thinset through the tile, and could tell the difference between ‘wet’ uncured thinset and cured. They watched that tile for 90-days seeing that grey spot shrink, until it finally was entirely dry. This is the reason Schluter doesn’t want you to use a modified thinset over Ditra…until that modified thinset has fully cured, it is still soft and being conservative, they do not want your installation to fail…a dryset (unmodified) thinset has many times more strength than the stresses that can be applied through the flexible Ditra uncoupling membrane. Think of the Ditra as the modifier in your thinset, and it can stretch MUCH more than a modified between two rigid surfaces AND, it reaches that strength in a know, short timeframe. IOW, if you understand how this works, your trepidation about modified goes away when told to use an unmodified when using Ditra.