Bona® R540 is a one-component, roll-on moisture membrane specially designed to mitigate vapor transmission on absorbent and non-absorbent subfloors, including Gypsum-based underlayment. The polyurethane reactive primer is compatible with the entire Bona Adhesive System.

• Helps mitigate potential moisture issues, like cupping*, originating from below the
membrane, in new and existing construction

• Can be used as a vapor retarder in place of felt paper for wooden subfloors up to 20% MC

• One coat can be used for damp proofing concrete subfloors up to 95% RH & 18 lbs**
• Dries fast allowing nail-down installation in 1-2 hours
• No more tears in paper or seams to be concerned with – continuous film offers more
uniform coverage and moisture protection.

COVERAGE (per 5L jug)
When used as a vapor retarder on unsealed wooden
subfloors: 1 coat at 300-400 square feet. When used
as a primer on sealed subfloor systems: 1 coat at 400-
600 square feet (test for compatibility).