How to Change a Leaking Metal Roof

Find the source of the leak. Detecting the exact location of the leak may be difficult as the slope of the roof may cause dripping into other areas. Look for areas where the metal panel has degraded. These panels may need to be replaced. Fastener holes may be a source of leaking as the holes can widen over time due to the expansion and contraction of the metal by heat and cold. Loosening may also occur at the J-rail. Sealant around seams may also deteriorate and cause looseness and leaking.

Seal enlarged nail or screw holes with neoprene washes or a dab of roofing cement.

Remove dirt and debris from any damaged areas.

Cut away the damaged section.

Lay butyl tape around the perimeter of the area to be patched.

Place the patch on top of the butyl tape. This patch can be cut from panels left over from the installation of your roof or from a scrap piece of sheet metal. Cut the patch 2 to 3 inches larger than the damaged area.

Screw the patch into position placing #12 self-tapping 5/16-inch hex head screws at 2-inch intervals.

Apply caulk around the edges of the patch.

Seal the seams of the patch thickly with roofing cement.

Alternatively, unscrew an entire damaged roof panel and replace it with a new panel, if the damage is extensive. Use #12 self-tapping 5/16-inch hex head screws to secure the replacement panel. Use neoprene washers to prevent leaks around the fastener holes. Screws should be only be driven into the peaks of the metal ribs of the panel.

Seal all seams with butyl tape or roofing cement.

Replace metal flashing in areas where chimneys or other system equipment penetrates the roof. Ensure that the flashing folds over the joint and connects beneath siding material or seals into mortar joints on masonry. Seal the flashing edges with roofing cement.