Expanding An Existing Gable Roof

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.

Expanding an existing gable roof.

That s a simple low cost solution that can tie in well with the main house. Slide flashing at least 4 inches under shingles on the existing roof and 4 inches down the new roof. If you re adding to the gable end of the house the side wall that goes up to the roof s peak it s fairly easy to extend the existing roofline over the new space says curt schultz a realtor architect builder in pasadena calif. You will need building help and a large construction dumpster for debris.

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. One would consider adding a gable roof to an existing roof for the following reasons. 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.

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. This is an especially effective strategy on a small lot and the addition is quite large. Extending a gable roof can be tricky since it involves working on the roof but you may be able to do it yourself if you only need to add 1 2 2 inches 1 3 5 1 cm. A gable roof would make the new room appear like it s a natural part of your home.

This may require removal of a second rafter. Nail new corner trim boards at the corners and put metal flashing on the roof connection. Install roofing to match the shed corrugated metal or oriented strand board osb sheathing and shingles. A stick framed roof with an attic has room to expand a dormer for example might create the additional space you need.

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. Look at a second floor addition in a more urban area with little opportunity to expand horizontally. It is not a job for beginners. 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.