A vapor retarder is often necessary when installing floating floors over concrete slabs, and sometimes even over wood subfloors, depending on the manufacturer's moisture test results. Concrete is porous and can release significant moisture vapor, even if it appears dry to the touch. This moisture can be trapped beneath the flooring, leading to mold, mildew, or, in the case of laminate, swelling of the core material. The vapor retarder acts as a barrier to block this moisture movement and protect the flooring assembly. Installation of a vapor retarder must follow the manufacturer's requirements, which may specify a minimum thickness, such as 6-mil polyethylene film. The seams must be properly overlapped and sealed with moisture-resistant tape to create a continuous barrier. Always check the moisture levels of your subfloor using a calibrated moisture meter before beginning your installation. Even if your flooring product is waterproof, moisture from the subfloor can still reach the underside and cause secondary issues, making a vapor retarder a vital component of a successful, long-lasting installation.
Key considerations
- vapor barrier under LVP
- moisture film under laminate
- floating floor over concrete
- vapor retarder
- concrete flooring
- floating floor