How to Lay Wood Floors on Cement

Installing hardwood floors on a concrete slab takes some pre-planning, but it can be done if you have some knowledge of construction methods. If you take necessary steps to ensure the correct installation, you could have a beautiful hardwood floors throughout your home regardless of whether it sits on a concrete slab.

Instructions

1. Make sure the concrete slab is dry before you start to install the floors. If you install the floors over a slab that is wet or even damp, your hardwood could buckle, gap or rot. Make sure that the concrete used in the slab has a low moisture content and also that a vapor barrier is laid before the cement is poured. This will keep moisture levels down.

2. Before laying down the floors, make sure the concrete is dry. Tools such as a relative humidity probe can be used to check humidity levels, but it is best to call in an expert. Before you lay the floor, install a vapor barrier to further ensure that moisture does not seep up to the wood. Some good vapor barrier materials are asphalt felt with asphalt mastic or 6 millimeter polyethylene sheathing.

3. Acclimate the hardwood by allowing it to sit inside the house to adjust to the temperature and the relative humidity of the home. Make sure all sheet-rock and any plaster used in the construction of the house is dry as well. Make sure that conditions are dry when the hardwood is delivered and, under no circumstances should you allow the wood to sit outside unprotected for any length of time.

4. Once the wood has been delivered, place it in the room where it will be laid. Ideally, it should sit in the house for about 5 days to properly acclimate to the temperature and humidity of the room. If you skip this step, the wood will shrink or swell once it is installed and cause gaps or buckling in the floors.

5. Clean the concrete after you are certain it is totally dry. Remove any dirt, debris and grease spots from the concrete.There are two options when you are installing wood floors that are 4 inches or wider plywood-on-slab or the top sleeper system.

6. Lay the plywood panels after the vapor barrier is installed. Make sure you leave adequate space at the wall line and in between the panels. Follow manufacturer's instructions for spacing and cutting plywood to fit near door jams. Lay the wood diagonally across the floor to prevent cracking. Nail the plywood to the concrete slab with the appropriate fasteners. Do not use glue to adhere the plywood to the concrete.

7. Lay your sleeers on the concrete slab. Sleepers serve as a nailing base on the concrete slab. They are treated 2x4s that are laid in random lengths, at right angles, on top of the vapor barrier. Make sure the end-joints are staggered and that you leave adequate spacing between the sleepers. You can also lay an additional vapor barrier over the sleepers to further protect your floors. Nail the flooring directly to the sleepers. Again, gluing the floors to the sleepers is not recommended.

8. Read the manufacturer's instructions before sanding or adding stain or sealant to the wood. Once the wood is sanded and smooth, it's time to add your stain (if needed) and then add a top sealing coat to protect the wood.

Tips & Warnings

• Always check with a professional regarding any type of do-it-yourself installation. Read the manufacturer's instructions that come with the wood for information on spacing, cutting, and using stain or seal on the wood.