How do you get a sag out of a gable roof?

Question

the addition is 16x20 on a 4/12

Answer 1

4/12 sounds like trusses nail planks across the bottom chords then make up some jacks and with use of a floor jack or other slowley jack it up 1/4" a day little at a time.I would wet the top chords around the sag as best as possible one of those rediculous steam clean machines on TV would be great for this. It will prevent the top chord from cracking. Once your sag is out brace the area very well and then some and release the jacks.

Answer 2

Your best solution there would be to check with your local home center or building supply center or possibly with the city or county building inspector to get a professional to repair the sag. At times what appears to be a slight sag in a gable roof could turn out to be a serious matter with the entire section of roof around the gable.
Play it safe and have a professional check it out for you. Sometimes the building inspector can help, as you normally will have to check from the attic or crawl space to see for sure what is wrong with the rafters or trusses which ever your roof is constructed with.