Double Felting Low Pitch Roof

Guide to roofing underlayment installation on low slope roofs with asphalt shingles asphalt shingles can be used on roofs with a slope of 2 12 to 4 12 if double coverage underlayment is used.

Double felting low pitch roof.

Even flat roofs have a pitch albeit a slight one. Overlay a second layer of felt 2 to 3 inches and fasten it through the overlay so it secures the top of the felt underneath. Roofing at low pitches counterbattens fixed to protect nail tape at the top of the rafters and nail tape over the rafters and other fixing points we all know that roofs are pitched to enable water to run off safely to the gutters without pooling and getting into the building structure. It looks as if there s no drip edge at the gable ends of the house so if you need to make a determination for sure your main task is not to fall off the ladder while looking under the shingles at the felt.

It has just one layer so it goes. The roof is low enough slope that double coverage would have made sense. The double felt solution has proven to be particularly useful for small roof areas which would be expected to discharge only a limited amount of rainfall. 21 degrees is a bit low for a slate roof i would contact the felt manufacturer for advice some are ok some are not.

Understandably the double felt method has been implemented widely within the industry to overcome low pitch problems. The arma s residential manual for asphalt roofing recommends that asphalt shingles on low slope roofs be applied over a nonperforated single layer of adhesive backed bituminous membrane installed to the manufacturer s specifications or over a double layer of asphalt impregnated felt paper. Discussion in builders talk started by mudhut sep 28 2006. A typical roof has three layers a felt layer and two layers of overlapping shingles.

Roll roofing is different. Sunday august 5 2018. The traditional metal roof types such as 5v crimp shown above and corrugated are rated by the manufacturers for use down to a 3 12 pitch three inches of vertical rise for every foot of horizontal run because of the shallow height of the undulating. But if you want to use felt paper you need to take additional steps.

In your cold climate with the possible danger of ice dams a bituminous membrane should suffice. Asphalt saturated felt along the eaves and lap succeeding courses by 19 inches as shown in figure 2 3. Page 1 of 2 1 2 next. 21 degree pitch double felting.

Can metal roofing be used on a low slope pitch roof. Snap a chalk line the. How to install roll roofing on low slope roofs.