How to fit corrugated PVC sheets

Corrugated PVC sheeting is an economical roofing material that is available in many different colours or can be transparent. With different thicknesses and strengths it is suitable for a wide range of uses from garage roofs to conservatories.

Requiring little maintenance and, being relatively easy to install, a correctly fitted PVC corrugated roof should last for many years before needing replacement.

Measure the length and width of the roof by using a tape measure. Multiply the two measurements together to get the total area of the roof. When purchasing the PVC corrugated sheets remember that the sheets need to overhang the verge of the roof by 2 inches. Also, each sheet overlaps the next as it is laid horizontally and by 2 inches vertically.

Measure the location of the purlins - the horizontal rafters - from the bottom edge of the roof to the roof ridge. Draw a line across one PVC sheet to mark the location of the purlins. Measure from the bottom of the sheet and add 2 inches to allow for the overhang and overlapping.

Lay the marked sheet upside down on soft ground. Drill holes, using a 3/8-inch drill bit suitable for plastic, along the bottom purlin mark in the lowest part of each corrugation and in each corrugation for the top purlin. Drill holes in every fourth corrugation for purlins in between the top and bottom. Use this sheet as a template to drill holes in the remaining sheets.

Lay the first sheet on the roof starting at the bottom corner furthest from the direction of the prevailing winds. Remember to set the PVC sheet so that it overhangs the bottom and side ridges by 2 inches. Hammer in 5/16-inch roofing nails through the drilled holes, into the purlins. Do not allow the corrugation to become compressed by the nails.

Lay the next sheet in the row overlapping the first and nail it in place. Overlap each sheet by a regular amount of corrugations so that you do not have to cut any sheets to size for the first row.

Cut the first sheet of the second row in half using a hacksaw with a blade suitable for plastic. Put one half aside to be used for the start of the fourth row. Lay the cut sheet with the manufactured, finished edge overhanging the roof verge, the rough cut edge will be hidden by the next overlapping sheet. Hammer the nails in place and continue laying the sheets, alternating the first sheet of each row with a full sheet then a half sheet.

Nail the ridge pieces along the top ridge of the roof starting at the furthest edge from the prevailing winds. Fit ridge pieces to the verges of the roof nailing them to the side barge boards.