Bona Polyurethane Primer/Moisture Barrier - 5L

Bona® R540 – One-Component Roll-On Moisture Barrier and Primer

Need serious moisture protection before your hardwood installation? Bona® R540 is a one-component, roll-on polyurethane reactive membrane designed to mitigate vapor transmission on a wide range of subfloors—including concrete, gypsum, and wood. Whether you’re installing floors in a new build or a renovation, R540 provides an easy, reliable solution for long-term protection.

Perfectly compatible with the entire Bona Adhesive System, this fast-drying membrane can also be used as a vapor retarder under nail-down wood flooring systems.

Why Choose Bona® R540?

• Protects against moisture up to 18 lbs MVER or 95% RH on concrete

• Fast drying—ready for nail-down installs in as little as 1–2 hours

• Zero VOC for safe, indoor use

• Easy roll-on application with ¼" nap roller—no seams, no paper tears

• Ideal for wood, concrete, gypsum-based subfloors, and radiant heat systems

Coverage:

• 300–400 sq. ft. per 5-liter jug (for vapor retarder applications)

• 400 sq. ft. per coat (for moisture barrier use with Bona adhesives)

Simply roll it on, let it dry to a transparent film, and move forward with your installation confidently.

Shield your flooring investment with Bona® R540—your simple, powerful defense against moisture!