Roofing Service

What is the best way to install a permeable roof membrane?

What is the purpose of a breathable roof membrane installation that makes it so popular? In pitched roofing projects, breathable roof membranes are essential because they prevent condensation from forming, leading to moisture, mold, and decay. They let moisture escape the roof area while preventing precipitation infiltration, keeping the space dry.

Moisture will seep through the exterior roof material, then build upon the insulation layer, rendering the insulation useless or even within the roof space, producing dampness, mold, and damage.

Breather roof membrane installation is a pretty simple process. But a few stages must be followed to create a breathable and secure surface.

  1. Support tray for the eaves

To begin with, an eaves support tray or a UV-resistant membrane installed along the eaves with the bottom edge reaching into the gutter is required.

  1. Place the breather membrane in place

Next, align the breather membrane with the roof eaves; generally, the printed side of the breather membrane should face outwards when installed. One should make sure the bottom of the membrane overlaps the eaves support tray or UV resistant membrane by at least 150mm, but not so much that the eaves support tray or UV resistant membrane is exposed when the roof tiles are installed.

  1. Ascertain that draping takes place

The permeable roof membrane should sag slightly between the timber rafters or counter battens, resulting in a 10-15mm dip. Once you’ve confirmed this, attach temporary clout nails to the top of the membrane, making sure they’re above the line where the second length of the membrane would overlap. The tiles or slates will provide a more secure fastening after installation.

  1. Place the rest of the breather membrane on top of it

Working your way up the roof, continue to place the lengths of the breather membrane. The amount of overlap necessary between each size of the breather membrane should be specified by each manufacturer. If the overlapping does not line up with a timber batten, a second batten can be put to keep the overlap and keep the tiles from touching the membrane.

These can be placed on top of the underlay, but the drape of the underlay must still be there to allow rainfall to travel through the membrane’s surface.

About the Author