I know what is wrong with my mother-in-law's sagging roof. It was originally built with 1x4 supports from the roof rafters(2x4) to the ceiling rafters(2x4). The ceiling rafters broke and the living room ceiling was also sagging. We pulled off the drywall and replaced the rafters with new 2x12 rafters. But now I need to install a stiffback (or strongback) and raise the roof. But the roof is heavy. How can I get it raised? I was thinking that I could build another stiffback and attach it to the lowest point, somewhere near the middle no doubt. But where is the bast place to put these? Should it 45 degrees top each other? How do I know ho long to cut the support beams? Any and all tips would be appreciated. We live in west Texas and do not have to worry about snow build up.

Not even close to a DIY job.
There's going to be a whole lot going on when someone starts lifting.
If you do not know what your doing on this one really bad things are going to happen!

not going to be on the same Web with this one. hire it out.

I think you should consult your local roofing contractor for this. They have skilled laborers who are experienced in their job and provide you better results.

This is a pretty broad statment I'm going to make and will not apply in all cases, but I would not use a roofer to try and fix a sagging roof.
Use a real contractor, as a general rule a contractor will know how it should have been built, should know how differant forces effect the whole building.
(for every action there's an opposite and equal reaction)

I think you should be aware that wood DOES bend over time with constant force on it. If you look at the flat roof of any old commercial building after a rain, there will be a puddle on it. That's because the joists holding up the roof have sagged over the 20 to 150 years the building has been there just due to the weight of the roof (and snow).

So, I'm afraid that what you MIGHT be dealing with here is not just the roof sagging against the force of the lumber trying to hold it straight, but the lumber itself having sagged and no longer being straight.

Straightening that bent lumber is not a practical option. It'll take as much force over as long a time frame to straighten it as it did to bend it. You will probably need to replace the bent wood, and that will require rebuilding part of the roof.

If the roof isn't leaking, then if it were my roof, I'd just leave it be until the next time you reshingle the roof, and plan to replace all or some of the rafters at that time.

This message has been edited. Last edited by: Nestor,

the roof is going to be a teardown and rebuild job, no question. down there in storm country, the roof should also be backed up with hurricane clips. you almost certainly have heard, "do it right the first time... use all the right contractors... use all the right products" as a "Holmes enthusiast." this is grade-A STRUCTURE. get a pro.