Metal roofing is held down more securely by screws than by nails, because screws have threads that dig into the wood underneath the metal roofing and give resistance to any forces that pull up on the roofing. Whether you are screwing down an existing metal roof from which old nails have worked loose, or a new metal roof that is being screwed down for the first time, the process is the same.
Things You'll Need
- Drill or screw gun with clutch
- Roofing screws with rubber gaskets
- Tape measure
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Test the clutch setting on your screw gun by driving a roofing screw through a scrap piece of metal roofing and into a piece of wood. Set the clutch so that the drill stops driving the screw at the point where the rubber gasket is snugly and firmly trapped between the metal washer on the screw and the metal roofing beneath it. If it's too tight, the rubber gasket could be damaged. If it's too loose, the hole won't be waterproof.
Drive a roofing screw into a lower corner of the roofing. Put the screw into the top of one of the ridges on the metal roofing.
Measure two feet up the roof from the first screw. Drive in another roofing screw at that point, on the same ridge. Work your way systematically across the roof, placing screws at regular intervals, so that you don't miss any sections of roof. To replace loose nails, pull out the old nails and put the new screws in through the same holes to minimize the number of holes you make in the roof.
Reposition any metal screws that spin without activating your clutch after you have put them in. These screws have failed to make a connection with the sub-roofing underneath the metal roofing.