Occasionally, a roof is encountered which is round or oval in shape. These roofs require special attention.
Additional labor costs are encountered on round roofs regardless of what type of roofing is installed. In some fashion, the product being installed must allow for the curve of the roof and for the fact that the roof gets narrower at the top.
Using metal roofing on round or oval roofs avoids the cost of future re-roofing. Standard corrugated or “sheet” metal roofing cannot be used on these roofs. When standing seam roofing is used, the panels must be tapered, meaning that they are wider at the bottom than they are at the top. The amount of the taper is carefully calculated based upon the diameter and height of the roof. Some manufacturers and jobsite rollformers can provide tapered panels. Classic Products’ aluminum shakes have also been used on round roofs, and an illustrated guide to doing so is available. The panels develop a curve in them if you turn them over and bend over the deep grooves by hammering on them. The more you bend over the groove and the further down the panel that you do it, the tighter is the radius that can be achieved. When installing these panels on round or oval roofs, careful attention must be taken to ensure that the courses are running straight. This is accomplished by regularly measuring the distance from the top of each course to the peak of the roof.