How to Find a Leak in a Metal Roof

Metal roofs on your home and outbuildings protect not only the belongings stored in them, but also the structure itself.

Finding the source of a leak immediately is crucial to keeping the wooden frame of the structure from rotting. Inspect both the interior and the exterior of the roof if necessary to find the leak.

Inspect the attic with the flashlight for any signs of leaks. Leaks can be identified by stains on the wood framing that makes up the roof structure, brown or gray discoloration, or black mold growth or black stains in a vertical line. Trace the darkest of the stains up to the metal roof itself. Chances are the leak is caused by an unsecured roof fastener such as a screw or nail. Search the attic along adjoining roof hips and valleys, as well as the peak of the roof for loose joints on the top flashing, (ridge cap). Inspect along any chimney structure where the roof flashing may be allowing water to seep through.

Access the roof exterior by positioning the ladder in a comfortable manner, following all instructions printed on the ladder's frame. Begin at the top of the roof and work your way downward. Inspect all fasteners, especially at the peak area, or ridge cap, of the roof. Check the joints where any two sections of the ridge cap mate. Visually observe the seal between all metal chimney flashing and masonry joints, as well as plumbing pipes that exit the roof line, which can be prone to movement from the fluctuation of extreme temperatures causing failure in rubber seals and caulked joints.

Press on the metal roof using your feet or hands around the roof fasteners. Screws and nails can pull upwards during extreme temperatures. The loose fasteners can cause holes to form under the rubber gaskets. Re-secure the fasteners using either a powered screw gun for hex head screws or a hammer on roofing nail heads.

Seal all suspect fasteners and joints using a high grade caulk. The caulk must be rated for use on metal roofs. Run new beads of sealant around all chimney flashing and gaps in the ridge cap material.

Things You Will Need

  • Flashlight
  • Ladder
  • Hammer
  • Powered screw gun
  • Caulking gun
  • High-grade roof caulk


  • Keep away from all power lines when using ladders.