How to Install Brazilian Walnut Over Concrete

Put the flooring boxes inside the space where you want to install the floor two weeks before installation. This allows the flooring to acclimate to the environment and install properly.

Cut four pieces of plastic sheeting into 12 by 12 inch squares with scissors. Position one square in each quadrant of the floor. Tape down the sides of the plastic sheet square with duct tape to seal in all four sides. Wait 24 hours. Check the plastic sheeting for moisture droplets on the underside of the plastic. This is a moisture test for the slab. If all of the sheets are dry you may continue to install the floor.

Prime the dry slab with a paint primer that is designed for this application. Often manufacturers have a group of products that work together. The primer you use needs to work with the mastic adhesive used for the vapor barrier. Follow the manufacturer's guidelines for the amount of drying time necessary for the primer.

Apply a coat of cutback asphalt mastic using a notched trowel. Work from the back corner to the doorway troweling the mastic directly onto the primed surface. Allow the mastic to dry for 2 hours. Unroll asphalt felt starting in the doorway. Overlap the seams by 4 inches. Butt the ends of the rolls. Felt the entire floor. Apply a second coat of cutback asphalt mastic using a notched trowel. Work from the back corner to the doorway troweling the mastic directly onto the felted surface. Allow the mastic to dry for 2 hours. Unroll asphalt felt starting at the doorway. Stagger the overlaps from the first layer. Do this by cutting the asphalt felt in half along its length for the first strip. Overlap the sides 4 inches and butt the ends.

Loose lay 3/4-inch thick exterior grade plywood over the vapor barrier on the diagonal. The diagonal keeps the panels from cracking along the edges. Keep the plywood 3/4 inch from the walls. Keep the plywood 1/2 inch apart. Trim the plywood to 1/8 inch in areas where trim will not be applied. Cut the plywood using a table saw and circular saw. Attach the plywood to the concrete with power actuated fasteners. Shoot a fastener into the center of the sheet first, then each corner. Apply nine or more fasteners per plywood sheet.

Snap a chalk line parallel with the longest wall. Check the corners for straight walls. Measure 3 feet from the corner and mark the wall. Measure 4 feet from the same corner along the adjacent wall and mark the wall. Measure between your marks. You should have 5 feet. If your measurement is different, you have one or more walls that are not straight. Check the wall parallel with the chalk line. If the parallel wall varies more than half the width of one floor plank you may need to floor in the opposite direction. Variations are more visible along the long or running length of the flooring where the floor can be compared to the wall.

Install the floor. Put long planks parallel with the chalk line along the longest wall. Insert a 3/4-inch spacer between the groove side of the plank and the wall. Use wood shims as necessary to keep the plank straight to the chalk guide line. Put a pneumatic hardwood floor hammer gun along the tongue of the plank. Hit a hammer against the nail deployment lever. Nail every 12 inches. Drive a face nail straight down 1 inch from the groove end of the planks next to the wall as they will be too close for the hammer gun to work well.

Paint all the cut ends of wood with wood sealer before installation, including ends cut by the factory. This prevents moisture from wicking into the ends of the planks. Stagger the board lengths randomly to keep joints and seams apart. Use scrap flooring to tap the tongue into the groove securely with a hammer. Cut hardwood flooring planks using a table saw. Leave a 1 1/4-inch gap between the hardwood and adjacent flooring. Install a reducer that fits the type of flooring. Do not allow the wood floor to directly touch the adjacent floor.