What to Use Under Laminate Flooring

Laminate Floors

Laminate flooring is an engineered product that is durable enough to stand up to high traffic and the day-to-day abuse that families and pets inflict on a floor. The floors are designed in a variety of hardwood styles as well as tile and stone. Laminate floors can be installed over most surfaces, including concrete, vinyl, linoleum, plywood and ceramic tile. Because the flooring is sensitive to moisture, it cannot be installed over any floor with a drain or with a sump pump in place. Bathrooms and laundry rooms, because of the high humidity levels, are also not suitable locations for laminate flooring.

Proper preparation of the subfloor will ensure a satisfactory installation of laminate flooring. Carpeting and padding must be removed from any subfloor prior to laminate installation. Other flooring products can remain, including vinyl, linoleum and ceramic tile. Plywood subflooring can remain unless it is installed on top of a concrete subfloor, in which case the plywood must be removed.

Laminate flooring should be installed over a clean and level surface. Check the evenness of the floor with a carpenter’s level and apply leveling compound to the surface if it is not even. Clean the surface of dust and debris before installing underlayment and flooring planks. The flooring planks need to be acclimated to the room prior to installation. Remove the planks from the boxes and stack them in the room for 48 hours prior to installation.

Concrete is a porous product that absorbs moisture, which is damaging to a laminate floor. Prior to installing a laminate floor over a concrete slab, the moisture level must be assessed and must not exceed 4.5 percent. To prevent moisture from damaging the laminate floor, a vapor barrier should be installed over all concrete subfloors, including those with an existing flooring product installed over the slab. An acceptable vapor barrier is high-density polyethylene sheeting that is 6 mils thick (0.6 millimeters or 0.006 inches). It should cover the entire floor with the sections of the sheeting overlapping by 8 inches. Seams should be sealed with polyethylene tape. Foam underlayment is then laid over the vapor barrier.

A foam underlayment is installed under laminate flooring. It reduces noise and provides cushioning. Some laminate flooring comes with the foam attached to the planks. If your product does not have foam attached, a layer of foam underlayment must be laid over any subfloor, whether wood or concrete. Foam underlayment is laid on the floor so that the edges butt together but do not overlap, covering the entire subfloor. The underlayment can be placed in the same direction as the laminate planks or at a 90-degree angle to the planks. The laminate planks are then installed over the underlayment.