I tiled our bathroom and mudroom in the new house. One of the issues I needed to figure out was the transition between the 3/8″ thick engineered wood floor and the adjacent rooms with tile. Traditionally I would have installed 1/4″ cement board under the tile. Then the adjacent wood floor would have needed a thin layer of wood underlayment to match up with the tile floor thickness. After talking to my cousin (he sells and installs flooring) he suggested that I try using the Schluter-DITRA underlayment under the tile floors.
Schluter-DITRA is polyethylene membrane with a grid structure of square cavities, each cut back in a dovetail configuration, and an anchoring fleece laminated to its underside. The biggest advantage to this product is it’s ability to act as an “uncoupling” layer. The membrane allows for in plane movement due to horizontal shear forces. You ask what the heck does that mean? Well in simple terms every time the floor changes temperature, moisture content or a load is applied (people) the floor flexes and causes a shearing force between the tile and sub-floor. This membrane allows for that movement without causing the tile to break.
The installation is actually quite simple. You role out the product (it comes in a role 3′-3″ wide) and cut it to fit the room. After you’ve cut all the pieces you adhere it to the sub-floor using thin set mortar. The fleece on the bottom of the membrane adheres to the sub-floor with the thin set. You use a regular rubber grout trowel to smooth out the membrane and make sure it is fully seated in the thin set.
The next step is to lay the tile as you normally would over a cement board application. The manufacturer even says you can apply the tile right away before the first layer of thin set has cured. I actually found laying the tile on this product much easier than the traditional cement board. The membrane is much softer to kneel on and the squares act as a great grid to help you maintain straight grout lines.
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I successfully used this product a year and a half ago and the tile floors are performing great. I even have radiant heat and that works great with this product. Next time I tile a floor I’m definitely going to use it. If you’re looking for cheap prices on Schluter Ditra then click the banner below.