How Much Should Roofing Felt Overlap

Make sure you have enough roof felt you don t want to have to stop mid way through the project to buy more felt.

How much should roofing felt overlap. In most cases this will leave 400 square feet 37 m 2 of net coverage per 1 roll. The felt must be flush at the rake side edges have 4 inch overlaps where two pieces are joined and 6 inch overlaps on hips and ridges. Some roofing felts are actually glued down. Position this strip so that it overhangs the top of the first sheet by 75mm.

If lap sealant is used simply apply a bead of sealant on top of the underlap ridge going all the way down the length of the ridge before the overlap ridge of the next panel is placed on top. Since you will have overlap between rows this works out to a total coverage area of 400 square feet the dimensions of a 20 x 20 roof. If this felt is either incorrectly situated i e. Adjacent pieces of drip edge should overlap at least 2 inches 51 mm.

These applications are ideal for flat roofs or protective surfaces under roof level decks. In other words if the height of the roof drops by 2 inches for every 12 inches in length you will need to use sealant to strengthen the overlap barrier. However you must allow for overlaps on joints. The overlapping felt creates a secondary barrier for moisture and wicks water away from the shingles above and the sheathing below.

Trapped behind the guttering or if it is badly weathered it needs to be replaced. The drip edge should extend at least 2 inches on the roof. The overlap of 3 8 should be followed consistently for a smooth look once the shingles are installed. Nail along the top of this strip at 500mm.

Tack the roofing felt down with 1 4 staples using an air compressor with a pneumatic stapler a hammer tacker or a staple gun every 12 inches. Must be installed at the rakes and eaves of the roof. The bottom course of felt on a roof called sarking felt ensures that all of the rainwater is correctly channeled into the gutter by protecting the eaves from any wind driven rain. One roll of conventional 15 felt covers 432 square feet 40 1 m 2.

Ensure that the felt lies flat and smooth before securing it. Where the sheets overlap apply roofing sheet adhesive using a disposable brush. Do the other side of the roof the same way also with an overlap at the peak. Purchase an extra pack of felt in case you need more or end up damaging your first roll.

Using a downwards brushing motion firmly press the top layer of roofing felt onto the adhesive taking care to ensure that the strip of felt does not ripple or crease. Work up the roof to the peak and fold felt over the top overlapping at least 3 inches and fasten it on both sides. Roofing felt is required to overlap 2 inches over the lower felt course. Take your second length of felt.