Concrete subflooring is commonly used in home building, and it is fairly easy to install beautiful flooring over the concrete. Laminate flooring is available in many forms and finishes, allowing you to create a customized look throughout your home. Floating laminate floors, like tongue and groove boards, require the floors to be level or the boards will not properly click together. With any laminate product, taking the extra steps to level your concrete subfloor helps keep the laminate finish smooth and straight.
Is Concrete Level?
Using a long level, you should be able to determine if your concrete subflooring is level across the length of the room. Set the level on the floor, and use a measuring tape to measure the height from the floor to the top of the level. Repeat every 6 to 8 inches across the length of the floor. If all the measurements are within 3/16ths of an inch of one another, the floor is sufficiently level, according to the experts at Lowes Creative Ideas.
Creating an Even Surface
Unfortunately, not all concrete subfloors are level. Failing to level the subfloor can cause your laminate to buckle and crack. Use the measurements you recorded in the previous step to help determine which areas of the floor are too high and which are too low. On the areas with the highest measurements, use a concrete grinder to sand out the bumps, creating a smooth, level concrete floor. In places where the floor dips too low, use a filling agent to create a level surface. Lowes Creative Ideas recommends using a cementitious leveling compound. Each brand differs slightly, so follow the manufacturer's directions as you apply the product and allow it to dry completely before applying laminate.
Before installing laminate flooring, concrete flooring needs to be clean and dry in addition to level. Any dirt and grime on the surface of the cement can cause damage to the laminate overlay. If the concrete is not sufficiently dry, the laminate will warp and bubble. Many home improvement stores sell concrete moisture kits that allow you to determine the moisture level in the concrete. The moisture level should never exceed 2.5 percent. For concrete flooring featuring underfloor heating, the moisture level should be under 1.5 percent, according to the Laminate Flooring Guide.
Before cleaning concrete, you must know what type of laminate flooring you are installing. Some laminates are glued down, while others float over the subflooring without the use of adhesive. Use a concrete grinder to remove any oil, adhesive or paint from the floor before gluing down laminate, then sweep and vacuum up any debris. You do not need to remove oil, adhesive or paint for floating laminate, though you should sweep the floor.