Homebuilding Information and Planning - How To Frame A Gable Overhang

How To Frame A Gable Overhang

How do you frame a gable overhang? It can be a little tricky for a first timer but it is actually a fairly simple thing to do.

A normal gable overhang is usually 12 to 24 inches wide. It is made up of rafters that are called fly rafters and are constructed of either 2x or 1x lumber. The fly rafters are usually one size smaller in width than the rafters used to frame the main roof. If the roof was framed with 2x8'sthe fly rafters would be 2x6's.

When framing the overhang I stop the ridge board with the last common rafter. By doing this I avoid having to cut down and reduce the size of the ridge to match the plumb cut on the fly rafters. If the common rafters were 2x8's, the ridge would have to be a 2x10. If the fly rafters were 2x6's, the 2x10 ridge would hang below the plumb cut of the fly rafter, putting it in the way of the finish soffit material.

When cutting the fly rafters three quarters of an inch must be added to their length to make up for the missing ridge. This is equal to half the thickness of the ridge. Four rafters must be cut to make the gable overhang, two for each side of the gable.

Let's say the overhang is to be 12" wide and will be made form 2x6. What we build will end up looking like a ladder. Two 2x6 fly rafters are seperated by 9" 2x6 blocks 24 inches on center. Starting at the bottom of the plumb cut, the blocks are nailed to the fly rafters and continue down to at least the birdsmouth cut.

Once the ladder is built they can be installed against the last common rafter. Before hauling the overhangs up, I like to start 16 penny nails in between all the blocking. This is to keep from trying to hold the overhang in place, and trying to start a nail, all at the same time.

The overhang is held tight to the last common rafter on the gable. The top of the fly rafter is held even with the top of the common rafter. The plumb cut on the fly rafter should line up with the center of the ridge board. When all these requirements are met, the overhang is then nailed to the common rafter. This procedure is then repeated for the other side of the gable.

The overhangs support themselves at the top as their plumb cuts lean into each other. They are nailed together. The bottoms of the overhangs are held up by being nailed into a 2x subfascia. Additional support is added when the plywood sheathing is nailed to the common rafters and onto the overhangs.

Gable overhangs built in this manner will provide nailing for whatever finish the soffit and fascia may be, aluminum, vinyl or wood.