When extending rafters the rule of 2 to 1 is usually sound.
Extending existing roof overhang.
Extending the overhang on your roof can be a tricky endeavor since it involves working on an elevated angled surface.
I limit the overhang to 2 ft.
The cost of extending my 30 foot long roof overhang 14 inches was 340 or 11 50 per running foot for materials.
If you only need an additional 1 2 2 inches of overhang this can easily be achieved as a diy project.
Start conventional overhangs by taking off the existing fascia and any other trim that covers the rafter tails.
Cut rafter tail extensions three times the length of the overhang that you want to add using lumber the same size as the existing rafters.
The eaves probably will be the easiest to extend because getting proper nailing on the existing rafters will likely be relatively easy.
A good estimate for a contractor to do this same roof overhang extension would range from 50 to 85 per running foot.
This cost did not include any labor or waste disposal fees.
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.
The installation of simple overhangs on a house involves nailing rafter extensions onto existing rafters.
Wider overhangs would require some engineering to ensure adequate support.