Need advice on fixing a sagging/drooping roofline

[greatjuan]

I had this same issue with a client of mine. They had a 'stick framed' roof out of 2x4 top and bottom cord with 3/8" plywood gussets on the joints. They gussets were only 8"x8" and were failing after a huge snowfall in '96. So..... how we solved this problem was like this; We had a 4" sag in a standard flat ceiling. Removed the drywall ceiling, v.b. and drywall. We gave the client a vaulted ceiling by contacting our local truss company. Had them come in and measure, produce the vaulted truss in 2 pieces so we could do the work from the inside as they had a new roof so we didn't want to remove it. Nailed the 2 halves to the existing trusses, joined the 2 pieces with 3/4" ply, PL400 and plenty of nails. Cut away the old truss to produce the vault. All engineered.
The troubled roof was from gable to gable so the gable ends had no sag. Strung a line under the peak on the vault. Raised each truss up individually, and made sure everything was looking good inside. The roofline on the exterior ended up looking good.

 

[redmondjp]

Well I ran string lines....bout an 4" drop in the worst area. I tried working from one end towards the middle jacking. All I managed to do was push up on one section, the decking still bowed in between the rafters and also the rafter cracked. So I sistered in a 2x6 beside it and tried lifting the 2x6, all that did was push up past the ridge plate. So I called back the contractor who came by while I was at work and asked if I just left it alone, could he shim the sag and he said yes. So im just going to leave it like it is and put things back together.

Next question, for roughly 39 sq, does 13,500 seem steep for a metal roof install in Florida?

Wait . . . what? You mean he's going to add wood on top of the sheathing so the new roof is straight? This gives me serious concerns about the wind resistance of the roof when completed (not to mention that it does nothing for the underlying structural deficiencies).

I don't have direct experience with metal roofing cost so I can't comment on that.

 

[boobag]

i'd run an lvl beam down center. redo the door header too with lvl and double cripples.
then you could sister new rafters next to existing to beef it up. after that i'd cut out those arches and flat spots on top.

 

[REDVETTE]

A lot of good advice given here for you but I believe your best bet is to rebuild your roof. I had the exact problem you do on a rental home that was built about 1960. There was no ridge beam used on my roof - only several 1X8's supported in place by 2 X6 rafters and held up with 2 X 4's above the flat ceiling. There are some pictures below of that old construction. With all the Earthquakes we get in my area, I'm surprised the roof did not fall into the house but it held up ok over the years but there was a noticeable sag at the ridge. I took the opportunity to fix the problem correctly with a full length ridge beam, new double 2 X 6 rafters and support beams from floor to roof to support everything. In addition, we removed a big brick fireplace that took up too much space (and the city has too many no burn days anyway) We decided not to replace the flat ceiling but left it vaulted which dramatically added to the feeling of spaciousness plus we had 4 skylights installed in the roof to increase natural lighting. The roof also got new plywood skin and new shingles. I'm more than happy with the result but it wasn't cheap, you get what you pay for! I would not have bothered with my structural problem except a tenant caught my kitchen on fire so I got a little insurance help but not much. If I were you, I would take some pictures down to your county's building department and talk to them about what you need to get a permit for this work. They can put you on the right track as far as whether you need an Engineer, an Architect or if you can do your own drawings. From here you can put a project budget together and work out the financing. Your last step would be obtaining bids if you will not be doing the work yourself. Good Luck!

 

[TractorJeff]

UM?
How old are you? Is it a "retirement" home for you? Will you be selling in the next 10 years?
I put tin on my garage which was a series of sheds built with 2 by 4 rafters and 3 layers of shingles. Taking all the shingle weight off actually allowed the roof to relax a little and not look so droopy. Like the other guy said, I would be leery of shimming to flatten what is there. In my opinion a steel roof weighs less than a shingled roof. In my case (snow) it is lots better as the snow doesn't stay on long!

 

[coldh2o]

Forty years old, been through a hurricane, no evidence of the structure being compromised (bowing walls, etc.). I lean toward poor quality control when the "trusses" were built and installed, the sag has probably been there forever.

Remove shingles to reduce dead load, shim and re-roof with the steel. Tying the bottom chords together properly when constructing the tray ceiling structure will reduce the possibility of future sagging.