How Much Overhang On Roofing Felt

Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials.

How much overhang on roofing felt.

Greater overhang becomes a point of leverage for gusts of wind to rip off your roofing. Roofing felt is required to overlap 2 inches over the lower felt course. Therefore a 2 inch overlap provides redundancy at the edges where the barrier is weakest. Nail the bottom edges in place and then nail along the sides.

The drip edge should extend at least 2 inches on the roof. Corrugated metal roofing generally comes in sheets that are 3x6 feet in size 18 square feet. Adjacent pieces of drip edge should overlap at least 2 inches 51 mm. The vertical leg of the drip edge should be at least 1 5 inches wide and extend at least 0 25 inches below the sheathing.

Measure the length of the roof and the breadth of one side. 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. About 1 inch just enough to assure the water goes into the gutter and not behind it. Some slight overhang is recommended in conjunction with a drip edge flashing to prevent water from getting under the roofing and onto underlying wood.

Multiply those numbers and then double the result for the square footage of your roof. The overlapping felt creates a secondary barrier for moisture and wicks water away from the shingles above and the sheathing below. Just below we illustrate shingles installed with too much overhang into the gutter. A conventional roll of felt is enough for 432 square feet.

Video of the day. This should give you a 1 inch overhang on the eaves including the top edge of the installed drip edge trim installed in step 1. Make sure you have enough roof felt you don t want to have to stop mid way through the project to buy more felt. The overhang to the next strip should be 3 8 inch.

Where a roll ends and a new one is begun the two rolls should be overlapped by four inches. The lower edge of the felt is overlapped 3 4 on top of and over the upper edge of the lower course of ice and water shield. All nails and staples should be placed on the lower half of the paper. The paper should then be nailed in or stapled every three to four inches across.

A typical metal roof overhang may be 2 to 4 inches or even less.