Rather than a single slope a gable roof consists of two slopes that meet at a peak running down the middle of the roof.
How to build a gable roof addition.
Determine the locations for your roof support posts.
When matched to the angle and proportions of other rooflines on the house your gable roof will add visual interest and character to the home making the addition look like an asset that belongs with the house.
Butt the first new truss against the old one.
Then load bearing roof beams fixed to the trusses are extended in the same way.
Tying in to an existing gable roof.
Use 8 penny nails to attach the first 2 in 4 in 5 1 cm 10 2 cm board to the wall studs.
For the arrangement of the gable end overhang for the standard roof you lengthen the ridge beam beyond the facade for previously verified length using cut rafters.
Tie into the end of an existing gable roof by removing existing facing boards wall siding and any other obstructions back to the first truss of the old roof.
After that you should fix the cornice board to the end sides of the ridge and the load bearing beams.
Adding one or more dormer windows to a gable roof is an age old way of adding living space to cramped quarters.
Nail 2 boards onto your walls as top plates.
Then mount new trusses on the new addition walls.
When you nail in the second boards offset the seams of the upper and lower layers by at least 24 in 61 cm.