When a laminate floating floor is installed over a concrete subfloor a moisture barrier must be used.

Failure to install a proper vapor barrier over concrete will likely result in a floor expanding. This will cause laminate floor problems such as cupping and gaps.

Always check a manufacturers installation instructions prior to installation to assure that proper procedures are followed and proper materials are used.

Do Not Use a Vapor Barrier on Wood Sub Floors

It is important to note that you DO NOT install a vapor barrier over a wood subfloor. Over wood a vapor barrier will trap moisture and cause damage. Some laminate underlayments are a combination of vapor barrier and foam so take care in selection.

A foam or other type underlayment approved by the laminate manufacturer needs to be used for installation over wood subfloor.

Vapor Barrier in Crawl Space Requirement

Crawl  spaces must have a proper vapor barrier ground cover spread over the soil. A crawl space must also have proper cross ventilation and no dead air spaces. Without the appropriate vapor barrier and cross ventilation, crawl space moisture will attack the underside of a subfloor and the back of the laminate flooring core. Excessive crawl space moisture may result in cupping of the laminate floor.

More Laminate Flooring Posts

• Laminated Flooring Installation Tips
• Water Damage Laminate Floor
• Steam Cleaner Damage to Laminate Floor
• Laminate Flooring Terms
• Chips, Dents, Scratches, Gouges in Laminate Planks