For example, a roof with a width of 15 ft (4. 6 m) and a length of 10 ft (3. 0 m) has an area of 150 sq ft (~14 sq m), which we then double for an A-frame roof. Fifteen percent of that number is 45 sq ft (~4 sq m), which brings the total estimated material needed to 345 sq ft (~32 sq m). The added 15% is to accommodate roofing overlap. Add another 5-10% if you want to be sure to buy enough.
In addition, space the lowest row of holes on what will be the lowest panels 6 in (15 cm) from the bottom of the panel. [5] X Research source
Alternatively, nail or staple your underlayment to the structure of the roof. If you’re installing your roofing over shingles, remove any damaged shingles first.
The flashing will overhang any gutters by about . 25 in (0. 64 cm). It’s totally normal, and there’s no need to remove or fiddle with the gutters.
Drive the screws so that the head of the screw just meets the corrugated panel and holds it securely, but no more, to prevent denting or dimpling the panels. Continue across the roof until the first row of panels is completed.
As you work, make sure the panels are square with the roof, to avoid laying crooked panels. Use a chalk line to snap down a grid that’s perpendicular to the edges of the roof.
Your ridge cap may require an additional closure strip and sealant. When in doubt, follow the manufacturer’s instructions. Once you’ve placed the ridge cap, seal any visible or dramatic seams with sealant.
PVC sheets are often cheaper than metal, but are much less durable. Other plastics, like polycarbonate or fiberglass, are much more durable than PVC, but are often more expensive. Plastic panels do tend to be noisier than metal in rain and hail conditions, however.
Terne tends to be the most expensive of the 3, and is often more difficult to work with.
