Installing Hardwood Plank flooring over Concrete
Wood is affected by climate change. The wood fibers expand and contract with fluctuations in relative humidity. This movement and the resulting moisture problems can be controlled with proper installation techniques and the use of high quality wood flooring products. If you’re going to be installing over concrete, it’s very important that you understand what part of the tree the boards are cut from and the manner in which the boards were processed. Both of these factors are vital to your overall success and satisfaction with the floor. Wood cut from the center of a tree contains a higher percentage of vertical grain which makes it less susceptible to movement and thus a higher quality material. Before you embark on this installation process certain rules of thumb to manage moisture and ensure the stability of the wood should be followed
- Be sure the wood supplier has properly dried the wood. (12 month air drying is reccomended)
- Let the wood acclimate in the home or business for 24 hours.
- During acclimation in your home or business, keep relative humidity at 45 percent.
- Make sure the wood flooring has proper stress reliefs. (These ridges on the underside of the wood relieve tension in wood, reduce board movement, and provide a greater glue surface.)
There are two options for installation of wide plank wood floors. Both options are driven by the height allowance between the slab and door. To determine height, measure the distance from the top of slab to the bottom of the exterior door or measure the transition to other flooring surfaces. Check accuracy by swinging door completely in both directions. Here are some step-by-step installation guidelines once you know the height allowance. We suggest you check with the manufactuer of you hardwood plank flooring for detailed instructions.
Option 1: Gluing directly to concrete — 1/2 to 3/4 inch height allowance Using either Bostik’s Best or Sika adhesive product, spread one layer of adhesive onto the concrete per manufacturer’s instructions and place your Carlisle planks, milled to 1/2 to 3/4 inch thickness directly onto the adhesive. Allow 12 hours drying time before finishing your floors.
Option 2: Concrete slab with plywood sub-floor — 1 inch height allowance Place a layer of 6mm polyethylene onto the concrete as your moisture barrier. Using a Hilti Direct fastening tool, shoot concrete nails into 1/2 inch plywood to apply directly onto concrete. Install Wide Plank Floors, milled to 1/2 inch thickness by blind nailing and gluing.
Option 3: Concrete slab with plywood sub-floor –1 1/2 inches or
more height allowance Lay down 3/4 inch plywood and then follow the directions above. The cost associated with both options for installing wood over concrete is similar. However, due to the cost of the adhesives, it can be slightly cheaper to use the plywood method. It’s also possible to install hardwood plank floors over concrete slabs with radiant heat. The installation process calls for using a floating plywood sub-floor. Proof that this method of installation has gained industry acceptance is its prevalence in high end commercial applications.
How to Install glue down Hardwood Floor & Engineered Floor on concrete cement