Breathable Roofing Felt Overlap

Breathable roofing felt also known as breathable roof membranes can be used within both walls and roof structures particularly when the external roof or wall materials are not completely watertight.

Breathable roofing felt overlap.

The felt from the second side of the roof needs to overlap the top of the felt from the first side and nailed through the top of the rafters on the first side. As you work the paper can be tacked down in the center so it won t blow away. The breathable roof membrane should drape slightly between the timber rafters or counter battens meaning there is a dip of around 10 15mm. Breathable roof membranes are generally installed on the cold side of insulation in the roof structure ie the side closest to the external area.

What is ice and water shield. At 1 meter wide this equals 50 square meters of membrane. Ice and water shield is a self adhering waterproofing underlayment that is used in roofing to help prevent damage caused by ice dams and wind driven rain. With a breathable membrane.

Overlaps must be provided with the minimum dimensions given on the printed overlap guide where possible eaves guards should be used to protect the product from sunlight and to direct water into the gutter. 4 1 it is often wrongly assumed that the breathable membrane is a straightforward replacement for the sarking or more traditional roofing felt normally used to the roof structure and once fitted there is no need to ventilate the roof space. Breathable roofing membrane prices. The roofing felt should be applied in layers that overlap.

Breathable roofing felt is typically priced by square meter with rolls available in standard 50 meter lengths. Roofing felt is required to overlap 2 inches over the lower felt course. Start at the bottom of the roofline and work up so any water that gets through the roofing material will shed down the tar paper and will not go under it. Video of the day.

Some manufacturers also provide a second width of 1 5 meters which gives a total of 75 meters squared. Therefore a 2 inch overlap provides redundancy at the edges where the barrier is weakest. Roofing felts are marginally breathable and certainly suffer from condensation through the winter months. The overlapping felt creates a secondary barrier for moisture and wicks water away from the shingles above and the sheathing below.