How to Repair a Metal Barn Roof

What You'll Need
Butyl tape
Caulking gun
Flexible putty knife
Galvanized metal
Rope (optional)
Safety glasses
Sheet metal screws
Tin snips
Wire brush
Work boots
Work gloves

It is not easy to catch a leak on a metal barn roof.  Because of the texture of the material and the slope of the roof, the water never leaks down in a straight line. It can leak down the sidewalls or pool up in places. Since a barn roof doesn’t have many obvious places for water to pool, you need to check the whole roof to see where exactly the leak is coming from. It could be in the seams between roof sections, around loose screws, around spiral nails if they were used in the original construction or any number of small places where water can sit.

A barn roof leak should be fixed immediately because much of the barn is likely made of wood and can be damaged easily by water.  Even small leaks can really do damage if left for long periods of time.

Step 1: Check the Surface

Begin by checking the entire surface area of the roof for leaks, including all seals, flashing and seams.

Step 2: Clean

Clean the area you need to patch thoroughly. Use a putty knife to scrape anything loose. Use a scrub brush or wire brush to get off all dirt. You can use a rust converter over any rust patches as well.

Step 3: Patch

Adhere about 1 to 2 inches of Butyl tape around the area you will be patching. Cut a piece of metal about 2 or 3 inches bigger than the hole and place it on the hole with the Butyl tape.

Step 4: Secure

Drill holes about 2 inches apart directly through the patch and through the roof. Use the metal screws to attach the patch to the roof. The screws can be closer together depending on how secure the patch is to the roof.  Sometimes 1 inch apart is better for securing some patches.

Step 5: Finish the Seal

Finish by sealing the repair with the caulk. Then, as soon as the caulk is dry use a roof coating on top of the repair.

Step 6: Preventing Other Possible Leaks

You might also want to tighten or replace any loose screws in the roof and cover the heads with roof sealant for a metal roof.


Since a roof is a very dangerous place, there are certain precautions you should be sure to take before attempting a repair.

  • Never climb onto a roof before you are sure it can hold your weight. Use something similar in weight to yourself to test the sturdiness of the roof trusses.
  • Use a board to walk along the trusses. The board should be 1/2 inch thick, 2 feet wide and 4 feet long. This is used so that the seams on the room do not split.
  • Never walk directly on the metal of the roof. Your weight should be entirely on the trusses.
  • Wear shoes or boots with traction since the roof can be slippery even when its not wet.
  • Never work on a wet roof.
  • You can take the extra measure of anchoring yourself with a rope tied to a tree or other structure on the other side of the barn.
  • When applying the patch, make sure you do no screw the roof to the rafters.