Generally speaking it will cost more to lift the roof on an attached garage than a detached garage.
Raise my garage roof.
You could brace the inside of your garage and use hydraulic lifts to raise the roof.
Consult a contractor for an estimate.
Additional support may be needed if the roof is not very stable.
Roof lifting cost for garage.
It has a pitched roof using modern w style trusses and concrete tiles.
Approaches to raising the roof.
Inside the garage tack two 12 ft.
The jacks should allow you to raise the roof a couple of inches at a time while the cripples you attached to the top plate and short studs will help keep the roof in place.
You might also try raising the actual garage itself but this obviously has structural challenges.
From the garage floor.
If for some reason you need to stop your project you can nail or screw the cripples to the original studs to temporarily secure the roof and resume when you are ready.
Roof lifting costs vary significantly.
Once the ledgers are up drive three double headed 16d form nails through the ledgers into each stud.
Long 2 8 ledgers to the northeast and southeast walls about 2 ft.
Prices fall anywhere between 5 and 20 per square foot and beyond.
The major downside to it is the height of the door opening at about 1 9m and the floor to ceiling height of approx 2 4m.