How To Install A Hardwood Floor Over Concrete

This article is divided into three sections. Below is what you need to know first before making a decision to use hardwood flooring over a concrete slab. Then read Installing Solid Hardwood Floor Over A Concrete Slab and Installing Engineered Hardwood Floor Over A Concrete Slab .

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What You Need To Understand Before Deciding To Use Hardwood Flooring Over A Concrete Slab

Before you buy a hardwood floor to install over a concrete slab there are several things you need understand and determine. It is best to write these down and use them during your shopping for hardwood flooring.

Grade Level

First off, where is the hardwood floor going to be installed? Is the concrete slab on grade (at ground level) or below grade (below the ground level, meaning a basement)? This is important because most manufacturers do not recommend installing solid wood floors below grade, which we will talk about in a moment.

New or Existing Concrete Slab

Secondly, is the concrete full cured? Is it a new concrete slab that has recently been poured, or is an older, existing concrete slab? Concrete slabs that are new require enough time to fully cure and to allow all the moisture within the newly poured slab to dissipate. Generally you are looking at least 6-8 weeks to fully cure. This may vary depending on your climate, time of year and concrete mixture.

Concrete Slab Moisture Content

Thirdly, how much moisture is in the slab? There are tests that can be run to determine the moisture content in the slab. Even old slabs can have lots of moisture in them. If you have to run a dehumidifier in the room all year round you may have too much moisture in that area to install hardwood flooring, especially solid wood flooring.

You can test for moisture evaporation in the concrete slab by taping a 16-inch square of clear 6-mil polyethylene film to the slab. Seal the 4 sides with moisture-resistant tape so the moisture cannot escape. Do this in several different areas around the room. (Sometimes moisture may be more concentrated in one area of a room than in other areas.) If no condensation collects under the film after 24-48 hours, the slab should be dry enough for floor installation.

Flatness of the Concrete Slab

Another thing that needs to be checked is the flatness of the concrete slab. This is the same thing as level. When any tongue and groove plank flooring is going over a subfloor is has to be extremely flat so the adjacent planks can be correctly fitted together. It is recommended that the slab be flat within 3/16" in a 10 foot radius or 1/8" within a 6 foot radius. Take a 6 to 10 straight edge and lay it on the slab at various places around the room and look for daylight underneath the straight edge. Any dips should be very noticeable. The dips must be filled in with a non-shrinking, mortar-type floor leveling compound before installation and allowed enough time to dry. /p>

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