Vapor Barrier Under Laminate Floor and Crawl Space
Line BreakAuthor: Terry Weinheimer | Kevin Weinheimer (14 Articles)
Kevin Weinheimer and Terry Weinheimer are nationally known flooring inspectors located in Oregon and offering nationwide service.
Interior Vapor Barrier Over Concrete Subfloor
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.
