Plastic roofing can come in a number of different sizes and styles depending on the region of the country. The most common style of plastic roofing is corrugated. There are a number of varying kinds of corrugated roofing, ranging from PVC to polycarbonate to plastic. Each type has a warranty, ranging anywhere from lifetime on down. Installing a plastic roofing panel is similar, but not quite the same as installing a shingle and can be completed by most home owners.
Measure the size of the roof to see how many sheets will be needed. Most sheets come in 1 by 1.5 metre (3-by-5-foot) sections. The recommended roof pitch is -12.2 degrees for plastic roofing. This is ideal to cut the plastic roofing panels to size with a fine-tooth saw blade or garden shears. For plastic roofing, garden shears will likely do the job.
Pre-drill the holes for the fasteners. These holes should be drilled at the high point of every fourth corrugation from the bottom of the roof panel. These holes must be between 8 to 10 mm in diameter and 5 cm (2 inches) wider than the fasteners going into the roofing. This will allow for expansion when the roof is exposed to the sun and heat.
Nail down flashing around the edge of the roof to prevent rainwater from leaking. This is not mandatory, but is best for a better seal. Fasten the panels to the roof with specialised fasteners. These have a waterproof seal underneath the head to prevent leaks. Continue to cover the entire area of the roof. Work from left to right, beginning at the bottom of the roof.
Overlap the panels by one corrugation. Seal the overlapping panels on the vertical side with silicone sealant. This will cover all gaps and spaces between the panels. Continue until the entire area of the roof is covered. Clean up the roof of any debris or left over materials.