wedi® Building Panel Over Concrete Subfloor

When installed over concrete, wedi® Building Panels function as a crack-isolation membrane, as cracks are not likely to transfer through the polystyrene core of the boards. The polystyrene foam also acts as a moisture barrier; thus, when the seams are properly treated, the system is 100% waterproof. The wedi® Building Panels are also used as thermal insulation, especially when installed underneath electric heating and floor warming systems. Heating cables and mats are typically embedded and encapsulated in a layer of tile adhesive mortar. Once cured, the installer sets tile in another combed bed of tile adhesive mortar on top. (Note: Please contact heating system manufacturer for proper installation methods over backerboard and never install heating and floor warming systems underneath wedi® systems to avoid heat being trapped.)

Produced with less than a +/-1/32” variance of thickness, wedi® Building Panels will provide a true surface on which to adhere floor tiles. wedi® underlayments have passed the Robinson Floor Test (ASTM 627) with a heavy-duty commercial use rating. To apply wedi® Building Panels over concrete, the floor must be clean and free of debris. Modified mortar, combed through with a 5/16” notch trowel, will then provide a ribbed bed on which the wedi® Building Panels will be laid. All joints should be staggered so that no seam continues throughout the length of the floor. After the mortar has set, alkali resistant fiberglass mesh tape, or wedi® sealing tape or wedi® polyurethane sealant should be applied to all seams, then tiling can begin.

Make sure the concrete floor is fully cured and free of debris, oil or waxes.

The panels are installed with modified mortar.

Stagger all joints when laying wedi® Building Panels on the floor.

Allow the mortar to set up, tape the seams with fiberglass mesh tape or use wedi® polyurethane sealant and set your tile!

wedi® Underlayment Over Concrete

wedi® 1/8”, 1/4” or 1/2” is the recommended thicknesses for floors.
Slab to be well cured and free of debris and waxy or oily films.
Variation in slab not to exceed 1/4” in 10’ span from required plane.
2” alkali resistant fiberglass mesh tape to be applied over all seams in dry areas. wedi® waterproof polyurethane sealant or wedi® sealing tape to be applied over all seams if a waterproof installation is required.