Solid wood floors are hard-wearing, need low maintenance and match almost any style of home. You can enjoy the beauty and charm of hardwood flooring, even if your home has a concrete slab. Installing the best wood floor to put over concrete needs considering some important factors and using the right techniques and skills.

Moisture Problem

The wood expands or contracts with increase or decrease in moisture. The wood flooring is usually nailed to the sub-floor. If you glue or nail the wood planks to the concrete, it will hardly allow any expansion and contraction. The planks may possibly warp and pop up due to moisture. The best wood flooring on concrete should have a vapor barrier and a wood or plywood sub-floor on concrete for fixing the wood flooring

Installing wood flooring on concrete at ground or above ground level is comparatively easier with right type of sub floors and vapor retarders. Moisture can be a big problem for solid hardwood flooring below ground level. 

Important Points

  • It is tedious to install a wood floor on a concrete floor as compared to installing it over a wood sub-floor. To get the best results, first you will have to install a thick sub-floor and underlayment. The combination of these practically raises the height of the wood floor by 1-1/2” or more, You should check the extra height to confirm that it does not create any problem with cabinets or in the doorways.
  • Concrete slabs must be dry before the sub-floor is installed. Check the moisture at several areas. If there is too much moisture you should not install hardwood floors.
  • A vapor retarder is essential over a concrete slab below even the sub-flooring material. Generally, a construction grade polyethylene film with minimum 6 mil thickness with perm of 0.13 is used. Other impermeable materials that have perm of 0.15 or less are also recommended. 

You can select any one type of the flooring from the following depending on the grade of floor and other considerations: 

Types of Flooring

Engineered Hardwood Flooring

It provides the best solution to solid hardwood flooring especially for below grade concrete floors. These floors have a top layer of hardwood species. The core is made by laminating multiple layers of plywood or high density fiberboard. The layers are stacked to counteract any natural expansion, contraction, cupping or warping due to environmental factors. 

Many engineer floors are floating type. These can be installed on a clean, dry and level concrete floor.

Click on Click Lock Flooring

This type of boards eliminates the need of nailing or applying glue to the grooves of the boards for installation. There are different styles of these boards. These can be easily locked into the mating end of already installed boards just by using a tapping block. Some board come with a foam layer underneath and can be directly installed on the concrete floors. Click on lock flooring is more suitable for at or above grade floors.

Normal Flooring

The normal way for installing wood flooring on concrete floor involves leveling and cleaning of the floor and laying a vapor retarder after priming it with cold, cut-back mastic with a straightedge or fine-tooth trowel. Polythene, asphalt felt or building paper is used as a vapor retarder. You can go for a sub-floor topped with 5/8” plywood or OSB made of ” thick plywood or sleepers. 

The plywood boards should be placed diagonally across the direction of the floor. This will help prevent cracks along the panel edges. The plywood planks should have 6”to 8” spacing in between and 2” spacing from edge. The plywood layer should float. No fasteners should penetrate the retarder or the concrete.

If you use sleeper, 2" x 4" kiln dried sleepers should be fixed over vapor retarder in rows with cold cut or hot. Asphalt mastic, in rows with a distance of 6” to 8” between their centers in a direction perpendicular to direction of the finished flooring. Fix a layer of polythene over the sleeper below the top up plywood layer you can nail the hardwood flooring to the plywood 

The wood flooring can be fixed to sub-floor by method recommended by the manufacturer for fixing the hardwood floor planks with mechanical fasteners cleats, nails, or staples. The best wood floor to put over concrete will meet your needs according to floor grading, your liking, ease of installation and the budget.