Tile Floor Underlayment
The materials that lie hidden beneath tile determine whether the tile will last for centuries or only a few years. A stable, firm subfloor; flat and even underlayment; adhesive that grabs hard; and long-lasting grout all contribute to a durable tile job.
Most flooring requires underlayment to cover imperfections in the subfloor, reduce sound and provide other benefits specific to each type of floor covering. It may not sound important, but it is essential! Choosing the right underlay product is important to getting a successful tiling project.
A strong underlayment is the most important part of the tile installation. There are several options for achieving a sturdy floor underlayment. Please feel free to call or email us TGN team can help you find the best option for you tiling project.
Specialists in Residential and Commercial Tiling Projects, we can help you with the following services:
» Help You Find The Best Underlayment Suitable Option To Your Project Needs
» Supply & Install
» Professional installation
» Demolition & Garbage Disposal
What is Underlayment?
Underlay is the layer of material directly beneath your floor covering. If you were to tear up the flooring in your home, you would likely find many layers. When you removed the floor covering, also called the finish floor, you’d expose the underlay. Remove that, and you would find a subfloor such as OSB (oriented strand board), plywood or concrete. A moisture and/or vapor barrier might be found among the layers too, especially in basement flooring, or the underlay might include a barrier in its construction.
Each finish flooring material requires an underlayment specifically designed to optimize its appearance, performance and durability. Depending on the flooring you are installing, the underlayment might be a hard material such as plywood or cement board or a soft material such as felt or carpet padding.
Tile Flooring Underlayment
Tile floors remain a popular choice, especially for bathrooms, entryways and other places a water-resistant surface is desired. The impressive variety of tile styles, shapes and colors allows you to customize your design.
Tile underlayment must provide solid support, so the tile and grout won’t crack when walked on. However, it must also be somewhat flexible to absorb movement and any expansion or contraction that comes with changing temperature and humidity. Two materials meet these requirements exceptionally well.
CBU or Cement Board Underlayment: CBU consists of cement material and fibers made from wood or cellulose. The fibers reinforce the cement and also give it a certain amount of flexibility that allows for movement without cracking the cement. Cement board is manufactured in several sizes including 3’x5’ which is the most popular and 4’x8’. Typical thicknesses are 1/4″ and 1/2″. It is also called cement backer board.
CBU or Cement Board Underlayment Installation: The board is typically nailed or screwed to the subfloor, though it can be glued as well. It can be cut with a utility knife or saw. Seams should be filled with thin-set mortar to create a more level surface for the tile.
DITRA Uncoupling Membrane: This premium underlay is manufactured from polyethylene with a unique design. DITRA features a grid structure of square cavities, the base of each cavity being larger than the top. This allows tile mortar, which bonds to the tile, to anchor within the cavity when it hardens. Check out our in-depth guide to Schulter Ditra.
The DITRA membrane, which is 1/8” thick, prevents the mortar from bonding to the subfloor. Instead, a fleece backing is laminated to the underside of the DITRA, and the backing is adhered to the wood or concrete subfloor using thin-set mortar.
DITRA is an underlayment that allows for movement and expansion/contraction while preventing the transfer of stress that commonly cracks grout and tile. This polyethylene membrane is an excellent moisture and vapor barrier too, and it can be installed over wood or concrete including floors with radiant heat. DITRA and the thicker DITRA-XL come in rolls 3’ wide.
Schluter DITRA installation: Installation is easily accomplished by rolling out the material with the fleece side down and using a utility knife to make cuts for obstacles such as drains and posts. Then, the material is rolled up again, and the floor is covered with thin-set mortar using a notched trowel. The DITRA is rolled out over the mortar making sure the fleece and mortar are in contact over 100% of the surface. A screed trowel or concrete float is used to press the material’s fleece into the mortar and to remove air pockets working from the center toward the edges.
Self-leveling Underlayment: If you’ve got an older home with concrete subfloors, then it is likely that those subfloors are cracked, uneven or have low spots caused by settling. You can’t install flooring directly over them and expect the job to look good or last.
The solution to installing flooring over concrete that is in poor condition is self-leveling underlayment, a concrete product that mixes quite thin and pours easily. Like any liquid, its surface will become level. This forms an outstanding platform for additional underlayment such as carpet padding, DITRA or plywood.
An additional benefit of self-leveling underlay is that it works well with radiant floor heating systems. The tubing the heated water is circulated through is placed on top of the old concrete, and the self-leveling underlay is then poured over the tubing.
Self-leveling underlayment installation: One inch is typically the maximum thickness this can be poured, and that’s plenty to cover radiant floor tubing. Low spots deeper than 1” will need to be filled with an initial layer of this material or with standard concrete before a self-leveling material is poured over it. The bag of underlayment will give complete instructions for mixing and pouring. You’ll need a 5-gallon pail, an electric drill and a mixing paddle. Typically, the pail is filled with water, and the mix is added slowly while the paddle blends it. Most materials need to be poured within about 10 minutes of when they’re mixed.
Dry Pack : Professional tile contractors often put down what they call a Dry Pack. It consists of a layer of roofing felt, then a wire mesh, then dry mortar.
Professionals swear that a dry pack is by far the best underlayment for floor tile, but it takes a lot of skill to finish it off level and at just the right thickness.
Leveling a floor using wire mesh and dry pack is a skill that is best saved for experienced professionals.
Dry Pack installation: The first step is to draw chalk lines on the walls that are perfectly level as a guide for placing the dry pack. You will need to plan for the height of doors and adjoining room floors as the dry pack and tile will add height to the existing floor. Depending on what the sub-floor is made of, you may need to spread a thin layer of self-leveling mortar to ensure that the dry pack bonds to the sub-floor correctly. Usually, for a concrete floor you will apply the dry pack directly.
Scratch Coat A thin mortar bed for use as an underlayment providing a sound, stable surface for bonding ceramic tile over Exterior Grade Plywood. Wood surfaces must be interior only and protected from moisture.
Scratch Coat Scratch coat consists of a mesh underlay fastened to the wood, overlaid with a thin coat of cement (thin-set mortar), which is a good under-surface for tile. Since floor tile is usually laid with thin-set mortar, cement bonds with cement perfectly.
Get a professional help for your project. Please feel free to call or email us, our experienced professionals staff are ready to help you.