One-Way Moisture Relief Vent

SKU: RV-600

The presence of moisture in a roof system can cause major problems down the line. Installing a One-Way Moisture Relief Vent can be a cost-effective and minimally invasive way to eliminate moisture under the roof surface.The MRV 600 Roof Vent is engineered to prolong the life of the roof system by reducing both moisture within the roof system and trapped air pressure within the building. 


The MRV 600 Roof Vent is a minimally invasive way to alleviate trapped air pressure and moisture under your roof surface. If left alone, air pressure and moisture can cause a reduction in thermal protection of the insulation and roof membrane system, leading to roof deck damage. The MRV 600 Roof Vent is designed to allow for the escape of air pressure and moisture in the roof system. The vandal-proof cap design provides security while preventing entry of wind-blown rain or snow.


Application: Recommended spacing is a minimum of one vent every 500 square feet. Cut a 4” diameter opening through the membrane and insulation material, remove material to vapor barrier or deck, lay vent on top of roof membrane and attach vent to the roof deck with the appropriate fastener. Install 4 fasteners per vent, evenly spaced. Clean area of vent that is to receive flashing material with clean rag and solvent to remove oil film from vent. Flash in MRV 600 Roof Vent with one of the two following procedures:

1. Apply a 3 course coating and fabric utilizing the PM PF200 Polyester Fabric and PM Silicone Coating.
a. Apply 12 to 15 mils of silicone coating over surface to receive fabric.
b. Embed fabric into silicone coating while still wet. Fabric should extend at least 2” on to the flange of the vent and at least 4” on to the roof surface.
c. After the base coating has cured, apply a generous coat of silicone coating over the fabric to ensure complete saturation.

2. Apply PM FT500 Self-Sealing Butyl Fleece Tape.
a. Install fleece tape a minimum of 2” on to the flange of the vent and extending at least 2” on to the roof surface per the application guidelines on the FT500 Technical Product Data sheet.
b. Apply a generous coat of PM Silicone Coating to the surface of the fleece tape. Ensure coating is applied generously to ensure a good seal over the fleece surface.

Note: If the roof system has an existing silicone coating, vent must be flashed-in with only the first option above as the butyl fleece tape will not adhere to the silicone coating.

Technical Documents