Wood Floor Q&A: Solid Wood & Concrete Slabs

The fundamentals of gluing down a wood floor are the same no matter whether it's engineered or solid. (Photo courtesy of Sika Corporation)

Can solid wood floors be installed over concrete?

Dre Eisenmann, product engineer at Lyndhurst, N.J.-based Sika Corporation, answers:

The short answer is "yes." The real first question is: What are the correct steps to use wood floor adhesives over concrete subfloors? No matter what type of wood floor you are installing—solid or engineered—the first step is making sure you have a properly prepared concrete subfloor. Here are some of the key questions I first ask myself:

• How old is the concrete—is it at least 28 days old?
• Are there any contaminates on the subfloor such as sealers, old adhesive residues or paint overspray?
• How flat is the slab? Is there more than a 3/16-inch variation over a 10-foot stretch (which would be unacceptable)?
• What is the moisture content of the slab?

All these questions help me dial in if there will be any additional subfloor preparation needed.

Now let's focus on what you asked about: the install. Which wood floor adhesive you plan to use depends on the style of wood flooring and moisture content of the concrete. Each adhesive manufacturer has a range of products to choose from depending on your own situation. Some of the key features you should look for when choosing an adhesive are the limitations of the wood size (for thickness and width) as well as moisture limitations for subfloor moisture levels. The Product Data Sheet for each product from each manufacturer will have the limitations for these values and will also tell you the proper-sized trowel to use. Trowel sizes are based on the sizes of your planks, as well as the whether the product is an adhesive-only versus a combination adhesive/moisture control product.

So yes, it can be done! As long as subfloor conditions are respected, and the proper wood flooring adhesive is selected.

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