@sheetmetalsamurai: How to Cut a Roof Pipe Penetration on a Sloped Roof When a round pipe passes through a sloped roof, the roof penetration is not a round hole. The opening becomes an ellipse because the pipe intersects the roof at an angle. In this sheet metal tutorial, I cut a piece of pipe to the roof pitch, traced the shape onto the roof panel, and cut the roof penetration with snips for a perfect fit. #sheetmetal #roofing #hvac #metalfabrication #carpentrytips