Do Corrugated Metal Roofs Have Gutters?

Corrugated Metal Roofs

• The ridges and grooves on corrugated metal roofing allow water to run down and off the roof. The metal panels are cut to length, and often a single corrugated panel extends from the ridge all the way to the edge. The corrugations on the sides of the panels overlap during installation to reduce the risk of water blowing under the panels from the side. Without gutters, water that runs off the roof will fall below the roof edge.

Foundation Problems

• Rainwater that falls from the corrugated roof edge can dig a trench in the soil along the edge of the structure and saturate the ground. Even if the building is a barn, it will have some type of foundation that is more likely to shift if the soil becomes saturated. When the foundation shifts, it can stress the frame of the structure. Guttering carries the water to one or more downspouts, which divert it away from the foundation.

Installing Gutters on a New Corrugated Roof

• On a new roof, the best way to install gutters is to attach an L-shaped gutter apron, which folds over the top edge of the fascia. Fascia is the vertical board at the end of the rafters. The metal roofing is next and should extend no more than 1 1/2 inches past the gutter apron. The actual guttering goes on last, attached to the gutter apron with brackets that screw through the gutter apron and into the fascia. For adequate drainage, a gutter should just barely “break level,” meaning it should slope only slightly toward the downspout.

Installing Gutters on an Existing Corrugated Roof

• If the roof already has corrugated metal but no guttering, you can still protect the foundation and the ground around the structure by installing gutters now. In this case, the metal roofing may extend a few inches, or more, past the fascia. Cut the edge of the metal roof back to within 1 1/2 inches of the fascia. Slide the gutter apron up and under the lip of the metal roofing. You may have to loosen one or more roofing nails if they are close to the edge of the metal to allow the apron to slide beneath. Attach the apron to the fascia and then install the gutters in the same manner you would for a new roof.