Expanding An Existing Gable Roof

This is an especially effective strategy on a small lot and the addition is quite large.

Expanding an existing gable roof.

A stick framed roof with an attic has room to expand a dormer for example might create the additional space you need. Tying a gable roof into an existing roof is a long expensive project usually undertaken only when there is a major addition or renovation to a house. But it is important that the roof pitch is exactly the same as the existing roof because you will see it from one roof to the other if it isn t. A truss framed roof on the other hand doesn t have any attic space to expand you re probably going to have to raise a truss framed roof to get more space.

One would consider adding a gable roof to an existing roof for the following reasons. This may require removal of a second rafter. Look at a second floor addition in a more urban area with little opportunity to expand horizontally. That s a simple low cost solution that can tie in well with the main house.

You will need building help and a large construction dumpster for debris. It s simple yet pleasing to the eyes. Slide flashing at least 4 inches under shingles on the existing roof and 4 inches down the new roof. A gable roof would make the new room appear like it s a natural part of your home.

For pitched roofs outriggers can be supported on the top of the gable wall end framing and extend back to the next truss or to a rafter. In case you don t know what a gable roof is it s the kind of roof that s formed as two slopes meet at the top. Install roofing to match the shed corrugated metal or oriented strand board osb sheathing and shingles. Where the overhang created is more than 450 mm and the roof is constructed with rafters the outrigger may need to extend back at least 900 mm.

With the roof pitch the same it doesn t matter if the new addition is slightly off in height or lined up front to back because you re going over or under the old roof. However for larger extensions you ll need to hire a professional to get up there and remove large portions of the roof before extending the overhang. Nail new corner trim boards at the corners and put metal flashing on the roof connection. You may need a structural engineer to help with design of trusses and rafters.