Bona R540 Moisture Barrier

Product Description

Bona R540 Moisture Barrier

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% moisture content.
• One coat can be used for damp proofing concrete subfloors up to 95% radiant heat/18 lbs.  Radiant heat systems will have a maximum moisture protection of 80% radiant heat or 6 lbs.
• Dries fast, allowing nail-down installation in 1-2 hours.  Surface should be dry to the touch.
• No more tears in paper or seams to be concerned with - the continuous film offers more uniform coverage and moisture protection.

Coverage and Application

• 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).
• For moisture barrier protection on concrete: 1 coat at 400 square feet (when used with 1250G or 1500G trowel and any Bona silane-based adhesive.
• Two coats at 400 square feet required for any other installations not meeting the above criteria.

Do not use Bona R540 for the following:

• On wet, contaminated, or friable surfaces.
• Over concrete curing compounds, sealers or other surface treatments that could affect adhesion.
• On areas subject to hydrostatic head.
• On cutback residue, or over vinyl/VCT/LVT.
• On chemically treated woods (stain, preservatives, etc.).
• As a leveling compound.
• As an adhesive.

Necessary Tools and Materials

• Bona R540 rolls easily with a 3/16 inch nap mohair roller.
• Do not exceed ¼ inch nap mohair or other shed-resistant rollers.
• Do not handle it until all safety precautions have been read and understood.  
• Wear eye, face, and respiratory protection.
• Wear protective clothing.

Drying Process

• Drying: 1-16 hours.
• Nail-down installation in 1-2 hours.
• Total cure in 24 hours.
• Do not allow foot traffic until the floor is sufficiently dried and cured.

Cleanup and Storage

• Bona R540 is difficult to remove once dried.  
• Take care not to step in the wet product to avoid unwanted transfer of material to other surfaces.  
• Wet material can be cleaned up with mineral spirit.
• Dried Bona R540 must be mechanically removed.
• Store in a climate-controlled environment. Keep from freezing. Do not store for extended periods above 90°F (32°C).

For more information: Bona R540 Technical Data Sheet.