Table of Contents
The roof
PVCPolyvinyl chloride. A common thermoplastic resin, used in a wide variety of manufactured products, including rainwear, pipes, garden hoses, phonograph records, and floor tiles. / Polycarbonate sheetAny broad, thin surface. roofing
Pvc and polycarbonate sheet roofing come in a variety of profilesBatter boards; Horizontal boards attached level to stakes, used to mark out the boundary of a construction and establish the levels and building line., sizes, and colors. Quality and prices vary immensely.
The most common profile is corrugatedHaving alternating ridges and grooves..
Quality varies enormously from cheaper pvc sheets up to lifetime guaranteed polycarbonate sheets and the price varies accordingly. Guarantees range from zero to lifetime.
Sometimes the cheapest is not the most cost effective. Pamphlets relevant to the type of sheeting required are usually available from most stockists, it is advisable to read them.
Roof pitch
Most type of PVC or polycarbonate manufacturers recommend a 10 degree pitch (approx 1 in 5.7 fallOf roof;Â Pitch; The incline angle of a roof surface.).
A lesser pitch could require additional weatherproofing such as extra flashings or appropriate sealants.
Cutting
Garden scissors or a fine tooth saw can be used to cut most sheets. The higher the quality, the easier the cutting. Sometimes a carborundum blade on a disk grinder will do the trick but only one sheet at a time or it could cause fusion and weld the sheets together.
Drilling
Pre-drill the holes in the sheets before fixing. The holes should be 8mm (5/16″) to 10mm (3/8″) and at least 2mm (1/8″) larger than the shaft of the screws to allow for expansion and contraction. Ensure the holes are in the high part of the corrugation. Sometimes it might be easiest to lay the sheets upside down on the ground and pre-drill. Another tip is to use a stick with a hole in it as a guide for the drill.
Fixing
Appropriate screws are readily available from any suppliers that stock the PVC or polycarbonate roof sheets. If the choice is available, hexagonalA plane figure with six straight sides. A regular hexagon is one with all six sides and all six angles equal, the angles all being 120°. Congruent regular hexagons can be fitted together to cover completely a plane surface. Apart from squares and equilateral triangles, these are the only regular polygons with this property. heads are the easiest to use. Most sheets should be fixed at every fourth corrugation and every second corrugation at gutters, ridging and overlaps.
Accessories
Accessories such as ridgeThe horizontal line at the top of opposing sloping sides of a roof running parallel with the building length. flashings, apron flashings and foam eave fillers are also readily available from any suppliers that stock the PVC or polycarbonate roof sheets.
I have generally followed this plan over an existing pergola, with modifications to suit my situation.
This site was the most helpful I have found.
For purlins (nogs) I reused existing 2x2s across the top of the rafters, planning to fix the Suntuf sheets to them directly.
This plan does not address painting, but I would observe that it is a helluva lot easier to paint structural wood components before installation. Most of the structure is the typical outdoor white.
Cut the rafters, angle the ends, and paint them on the ground, to save a lot of work.
After hammering or bolting the steel anchors and truss ties, I hit them with some white spray primer to hide the nail heads and hammer marks.
I am using the smoked gray Suntuf, and I wish I had painted the purlins more of a matching gray color (instead of white) before screwing them down to the rafters. I would prefer the purlins to fade out of view against the polycarb sheets.
The plan and equipment list make no mention of the foam closure strips offered by Suntuf, to match the contour of the sheets across the top of the purlins. I am planning to use them, hopefully to provide some noise damping, and wonder if paint will have any effect on them. They are supplied in bright white, which would upset my gray “camouflage” scheme.
Also, the closure strips are very lightweight and make placing the sheets difficult, especially if you are doing this singlehandedly. A couple little folded pieces of duct tape keep them on the purlin when sliding the sheet into place.