Installing roll roofing correctly on your flat-roof storage shed is vital in keeping your storage items dry. The choice of roll roofing material depends on the pitch of the flat roof, because this type of construction typically varies between 1/2 to 2 inches of slope per foot of running roof length. Standard granular surfaced roll roofing is suitable for a 1- to-2-inch pitch but for an even gentler sloped flat roof, a peel-and-stick type of roll roofing with its flat surface provides an appropriate watertight finish.
Things you need
Asphalt-based granular coated roll roofingRoofing nailsLap cementAsphalt-based peel-and-stick roll roofingDegreaserHand rollerUtility knifeScissors
1 Use a concealed-fastener system with standard asphalt-based roll roofing for your shed roof. Measure and cut lengths of roll roofing to cover the roof in courses parallel with the lowest roof edge. Add an extra 1/2 inch to create a 1/4-inch overlap at the side edges of the roof.
2 Measure and cut a 9-inch-wide roll roofing strip to install around the perimeter edge of the shed. Overhang the perimeter edge by 1/4 inch and fasten with roofing nails in two rows, one inch in from the sides of the strip at 4-inch intervals. Lay the first course of roll roofing flush with the underlying overhang and nail the top edge at 4-inch intervals.
3 Spread lap cement over the 9-inch-wide perimeter strip and bed the top roofing layer into the cement, using a hand roller. Overlap each course by at least 2 inches and use lap cement to fasten the upper roofing layer to the previous roofing course.
4 Install asphalt-based peel-and-stick roll roofing on your shed if the slope is as low as 1/2 inch per foot. Clean the shed's roof deck with a degreaser to prepare a spotless surface for effective adhesion. Allow the deck to dry.
5 Measure and cut lengths of the peel-and-stick type of roll roofing to match the width of your shed roof. Lay the length parallel and flush with the lowest edge of the roof.
6 Peel away a few inches of backing at a time and press the roofing onto the roof deck. Use a hand roller to apply uniform pressure over each completed course. Overlap each course by three inches to gain optimal performance, as recommended by most manufacturers.
Tips and warnings
Stack the roll roofing in lengths to acclimatise in warm weather in order to make the roofing easier to handle.
Use a utility knife to cut granular-surfaced roll roofing and use scissors to cut peel-and-stick roofing.
Unless your shed roof is very large, avoid the need to overlap end pieces by cutting full lengths of roll roofing to fit the width of your roof.
For large sheds, overlap end pieces by six inches.
Take care when installing roofing on your shed to ensure the structure is weight bearing.