How to Lay a Floating Wood Floor Over the Crown in a Concrete Floor

Clean the concrete floor surface over which you want to lay a floating wood floor, using a wet mop. If the mop doesn’t remove all greasy spots, use a little anti-grease soap on the floor.

Cut a plastic vapor barrier into strips long enough to stretch all the way across the room in one direction. Lay these strips side-by-side on the floor, with each strip overlapping the strip before it by 5 inches, from one side of the room to the other, until the strips line the entire floor.

Start at the side of the floor where you placed the first strip. Roll up the edge of the strip next to it, so that it no longer overlaps the first strip, and roll back 2 feet at one end of the first strip to peel off the backing that covers the adhesive. Once you have the backing out of the way, press the strip down into place against the wall, so that the corner of the strip lines up with the corner of the room.

Peel off the rest of the vapor barrier backing a couple of feet at a time, pressing the strip into place on the floor as you peel the backing away. When you finish the first strip, move onto the subsequent strips and attach them, using the same process. Cover all of the seams between vapor barrier strips with plastic tape.

Measure the length of each wall of the room. Cut wood boards that are 3 inches in width down to the size of each wall. Place the wood boards directly against the base of the walls, so that they sit 3 inches tall on the floor, and secure the boards to the floor with 4-inch concrete screws.

Use the tape measure to place a 3-inch tall wood board that stretches all the way across the floor from one wall to the other, every 12 inches across the floor’s surface to create joists for a new wood floor. If the crown of the floor has less than a 12-inch diameter, place boards on either side of the crown so that the crown doesn’t interfere with the height of the joists.

Lay joists over a crown that has a diameter wider than 12 inches. When you place joists on the crown, set a builder’s level between the joist that sits on the crown and the nearest joist that sits flat on the floor to get an idea of how much the floor slopes due to the floor crown. Once you have some idea of how much slope the crown creates, start sanding the bottom side of the joist to fit around the crown in the floor.

Sand the bottom of the joist that must pass over the crown in a concrete floor in an arcing pattern to round the edge of the joist inward. Use the crown of the floor as a guide, laying the joist back into place over the crown and checking it with a level frequently as you sand. Once you get the joist so that it sits level with the other joists, secure it to the floor with concrete screws.

Lay a plywood panel over the joists in the innermost corner of the room so that it lines up with the corner. Secure the plywood to the joists with 2- to 3-inch wood screws every 6 inches. Continue attaching plywood panels to the joists until the entire floor has a flat wood surface.

Install the floating wood floor over the new wood flooring surface. Follow the directions provided with the wood flooring to ensure a successful installation.