What wood flooring can be installed over concrete?

Installing wood flooring over concrete can transform a drab concrete floor into a beautiful warm wood surface. However, not all wood floors are suitable for installation directly over concrete. The concrete needs to be properly prepared and certain types of wood flooring are better choices than others. In this article, we will discuss the requirements for installing wood floors over concrete and provide recommendations on the best wood flooring options.

Can You Install Any Wood Flooring Over Concrete?

No, you cannot install just any wood flooring directly over concrete. Hardwood floors like oak, maple, and hickory are not good choices as they are not dimensionally stable enough. The concrete will transfer moisture up through the wood causing the planks to expand and contract with changes in humidity. This movement results in gaps, cupping, and other problems.

Here are the main factors to consider when choosing a wood floor for concrete:

• Stability – The wood needs to be engineered for minimal expansion/contraction.
• Moisture resistance – It must have a durable moisture barrier.
• Adhesive – Use an adhesive that bonds well to concrete.

The best options are engineered wood floors with layered wood and stabilizing cores. Solid hardwoods are susceptible to moisture damage and movement over concrete.

Engineered Wood Floors

Engineered hardwood is constructed with a top layer of solid wood (usually oak or maple) bonded to layers of plywood below. This creates a plank that is more dimensionally stable than solid wood. The cross-ply construction and adhesive reduce expansion and contraction.

Most engineered wood floors have a factory applied moisture barrier on the bottom. This provides protection against moisture coming up through the concrete. Durability and thickness of this barrier can vary, so choose an engineered product rated for concrete installation.

Here are some great engineered wood flooring options for concrete:

Engineered Oak Flooring

Engineered oak flooring gives you the classic beauty of oak over concrete. The dimensional stability prevents excessive movement and gaps. Choose at least a 1/2″ thick engineered product rated for concrete. A thick sawn face oak layer looks most authentic.

Engineered Hickory or Pecan Flooring

For a unique look over concrete, choose an engineered plank with a hickory or pecan solid wood face. These species provide nice color variation over the grey concrete. Durable moisture barriers are important with the porous nature of these woods.

Engineered Exotics like Tigerwood

Concrete has a modern, industrial look that can pair nicely with many exotic woods. Tigerwood is a good example that is often available as an engineered product. The rich brown and black coloring over concrete can be quite striking.

Engineered Bamboo Flooring

High quality engineered bamboo is an eco-friendly option on concrete that is very durable and stable. Strand woven bamboo offers great moisture resistance. Solid bamboo is more prone to expansion and contraction over the concrete.

Moisture Testing Concrete

Before installing any wood flooring, it is crucial to test the concrete moisture levels. Concrete naturally has high moisture content from the curing process. Excessive moisture passing through the flooring can cause damage like cupping, swelling, and seam failures.

Here are two common methods for testing concrete moisture before wood floor installation:

Calcium Chloride Test

This quantitative test involves taping a test kit to the concrete and measuring moisture absorption. Results below 3 lbs per 1000 sq ft in 24 hours are generally acceptable for wood floors. Between 3-5 lbs may require extra vapor barrier precautions. Over 5 lbs is generally too wet for wood flooring installation.

Plastic Sheet Test

This qualitative test involves taping down a plastic sheet (2ft x 2ft) for 24 hours. If no condensation or darkening appears underneath, the concrete is likely dry enough. If moisture accumulates, further testing is needed before installing wood flooring.

Perform 3-5 moisture tests across the concrete and keep documentation. If moisture levels are too high, drying time or concrete sealing may be required. Retest until safe levels are achieved.

Preparing Concrete for Wood Flooring

Once moisture testing is complete, preparation steps are vital for proper adhesion and preventing moisture issues:

pH Testing

Test the pH level of the concrete. A pH over 10 can break down adhesives over time. Use self-testing litmus paper kits or metering devices. Neutralizing concrete acidity may be required if pH is over 10.

Cleaning and Leveling

Concrete must be free of paint, wax, oil, dust and debris. Use a concrete degreaser and then a wet/dry vacuum. Grind down high spots and fill divots and cracks with a concrete leveling compound. This provides a flat, smooth surface.

Vapor Barrier

In addition to the wood flooring’s moisture barrier, install a polyethylene film vapor barrier over the entire concrete. Overlap seams 6-12 inches and seal with moisture resistant tape. A second plastic layer provides added moisture protection.

Adhesives

Use adhesives specifically designed for concrete applications. Urethane or silicone adhesives bond well and resist moisture. Follow all manufacturer application and cleanup instructions.

Installing Engineered Wood Floors on Concrete

Once prepped, engineered wood flooring can be installed directly over concrete. Follow all manufacturer guidelines for layout, expansion gaps, and nailing patterns.

Here are some best practices for installation:

• Control indoor humidity between 35-55% year-round.
• Leave 1/4″ expansion gaps between flooring and walls/fixtures.
• Stagger end joints by at least 6″ between rows.
• Blind nail planks into the concrete using an engineered flooring nailer.
• Roll/tap planks to ensure adhesive transfer from subfloor.

Allow the adhesive to fully cure for 24-48 hours before light foot traffic. Wait 72 hours before moving furniture onto the new floor.

Maintaining Engineered Wood Floors on Concrete

Engineered wood flooring on concrete requires some special maintenance:

• Check humidity levels and use dehumidifiers to keep 35-55% humidity inside.
• Immediately clean up spills to avoid moisture seeping between planks.
• Use rugs over high traffic areas to prevent wear and scratches.
• Vacuum or dry mop regularly to remove grit that can damage finish.
• Reapply protective finishes per manufacturer instructions to renew wear layer.

Avoid excessive water and steam mopping. Test cleaning products on a sample plank before using on floor. Harsh chemicals can damage concrete anchors and wood finish.

Can You Install Solid Hardwood on Concrete?

Installing solid 3/4″ thick hardwood planks directly on concrete is possible, but comes with some caveats:

• Not recommended for below grade concrete or basements prone to moisture.
• Concrete must pass moisture testing with maximum 3 lbs per CaCl test.
• Use very moisture resistant wood species like mesquite, white oak or domestic maple.
• Thicker planks are more stable than thin; minimum 3/4″ thick.
• Allow proper expansion gaps between planks and perimeter.
• Use adhesive rated for moisture resistance and concrete bonding.
• May require frequent seasonal gap filling and finish repairs from movement.

Given these requirements, engineered hardwood is generally a better option for concrete subfloors. The plywood core provides crucial stability and prevents moisture damage compared to solid wood.

Can You Install Laminate or Vinyl Wood Flooring Over Concrete?

Floating laminate and vinyl wood plank floors can also be installed over concrete. The major benefit compared to real wood is laminates and luxury vinyl are not prone to moisture damage or expansion/contraction issues.

Here are some tips for laminate and vinyl wood flooring on concrete:

Laminate Flooring on Concrete

• Use laminates rated for concrete use like 12+ mil attached underlayment.
• A separate vapor barrier is still recommended.
• Match transition moldings to allow slight floor movement.
• Use wax/oil impregnated laminate edges for moisture protection.
• Avoid cheap, thin laminates not made for concrete.

Vinyl Wood Planks on Concrete

• SPC and WPC vinyl planks have excellent concrete resistance.
• Cushioned backings improve sound insulation.
• Use premium waterproof vinyl rated for basements and concrete.
• Vinyl requires no acclimation time.
• Can use moisture resistant adhesives or float over underlayment.

Both laminate and vinyl wood provide great looking, affordable wood looks over concrete floors without the installation and maintenance demands of real hardwood.

Conclusion

Transforming a raw concrete floor into beautiful wood flooring is possible with the right products and preparation. Engineered hardwood floors provide the most authentic look and feel. Laminate and vinyl wood floors are cheaper, easier alternatives. The keys are proper concrete moisture testing, vapor barriers, and wood flooring engineered for stability over concrete. With the right flooring and installation process, you can enjoy durable, stunning wood floors over your concrete foundation.