How to Repair a Hole in a Metallic Roof System


When properly installed, a metal roof system’s life expectancy is second to none. But like all roof techniques, they require regular maintenance and repair. Roofing repairs can be a very puzzling process. Done properly repairs can outlive the roof system that they have been applied to. Done improperly, those same maintenance can continue to crack and fail departing the homeowner or building owner by using a continual leak issue. A recurring leak condition can be a way to obtain aggravation but also can bring about interior building injury and potential mildew growth. It is always better to fix the problem right the 1st time and be assured that your solution will supply your goal of a watertight roof system for long periods time.

Repairs for the surface of a metal roof system can prove to be one of the more difficult repairs to complete. Metal roof covering repairs are prone to early failure due to the distinction in the expansion and contraction of the metal roofing panels in comparison to the applied repair. This difference in expansion and contraction between the two products places stress on the repair and leads to ultimately, cracking and splitting failure of the patch. The following is a recommended process for completing a repair for a hole in a metal roof system.

Tools needed:

Metal snips

Cordless drill

Wire brush

Caulk gun

Paint brush


Materials needed:

Sheet metal – ensure that the type of sheet metal matches the type of metal used in the roof

Urethane sealant – matched as closely as the color of the metal panel being repaired

Pan head sheet metal screws

Paint – color matched to the metal panel being repaired

Simple Green or other cleaner – it is recommended that the cleaner does not leave a residue

Step One — Clean Repair Area

The hole in the metal roof system may have been caused by any number of sources. The hole may be from rust and deterioration or it may be from something falling onto the roof surface such as a large branch. No matter what the cause of the hole, the area of the roof where the hole has occurred is most likely dirty and requires cleaning.

Clean the surface of the metal panel using Simple Green or other cleaner. Clean the surface of the roof panels until any dirt, film or algae growth is completely removed. Any residue will compromise the integrity of the roof repair. After cleaning the surface of the metal panel, use the wire brush to scuff the surface of the metal panel where the repair will be installed. The wire brush scuffs the surface to allow the sealant being applied to attach to the surface and not to simply sit on the surface of the metal panel. The wire brush is to be used only in the area where the patch will be installed. Wire brushing beyond that may remove the protective coating from the metal panel surface causing deterioration of the panels.

Step Two — Cut Repair Patch and Area

Cut the sheet metal to a size that matches the area to be patched. The sheet metal patch should bear on metal panel a minimum two inches past the leading edge of the damaged area. After the sheet metal patch has been fit and cut to size, round the corners of the patch to prevent any sharp corners from becoming a catch for snow or ice.

Once the patch has been measured place it over the hole being repaired. Take your pencil and outline the patch. Remove the patch and ensure that there is a minimum of two inches in all directions past the leading edges of the hole in the roof system.

Step Three — Install Repair Patch

Apply the sealant to the surface of the metal panel being repaired. The sealant should be applied so that it is just inside of the marked pencil line. Apply the sealant liberally in the area so that there are no gaps or voids at the leading edge of the patch.

Take the patch and press it into place. The sealant should bleed from the leading edge of the patch along all sides. If there are areas where the sealant is not extending from the edge moisture these are areas where moisture can penetrate under the patch causing a deterioration of the patch.

Step Four — Secure Patch

Once the patch has been pressed in place, attach the patch to the surface of the metal roof panel using the pan head sheet metal screws. Apply the screws at a rate of three to four inches on center around the perimeter of the patch. The screws should be applied within one inch of the leading edge of the patch so that they apply uniform pressure to the leading edge of the patch and the sealant beneath the patch.

As necessary after the patch has been attached, retool the sealant that is bleeding from the edge of the patch. This will ensure that the sealant properly seals the leading edge of the patch and prevents moisture from penetrating the leading edge.

Step Five — Paint Patch to Match Roof

The surface of the patch can be painted to match the color of the metal roof panels if desired. In order to complete this, lightly wire brush the surface of the metal patch and the metal panel just past the leading edge of the patch. Apply the paint to the surface of the patch and onto the surface of the underlying panel. Be aware that it may be necessary to wait for the sealant used under the patch to cure before applying paint to the surface of the sealant. In addition, confirm that the paint selected is compatible with the sealant that was selected.


Safety is a major concern with completing any roof repair project.  A hole in a roof system may be an indicator that there are other concerns about the overall structure including decking deterioration.  Be sure to conduct a proper under deck safety roof and review analysis before attempting to complete this or any roof repair.  Contact a professional roofing contractor like     F&B Painting who can complete the repair for you in a safe and professional manner if there are concerns about completing your roof repair safely.

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