Sagging Roof Insight

[EricU]

I feel like making that roof go back up and the walls inward is not going to happen that easily.  Seems that to winch it inward, you would probably need many winches and a way to spread the load along the wall.  And the roof angle is rather low, so it's not going to want to go up easily.  Jacking the center beam seems like the best start.

OTOH, your walls have nothing keeping them out or in, so they might move back into place if you jack up the ridge beam.  

I am thinking that it would be prudent to put in collar ties at the current location just to avoid catastrophic failure.  That puts an actual repair off for a while. Around here, that roof would be gone by now due to snow load.

[Snipe Hunter]

Holy crap!. Ceiling joists 90 degrees out from rafters.  There is no structure to keep the walls from spreading (and the roof from sagging).    You need collar ties or add a true ridge beam and support to ground.  

You probably need to pull the walls in first too.

Yikes!

Collar Ties and a come-along and a jack.

I'd probably lay a few 4x4s across those joists and some jacks from the garage floor to a board running perpendicular to the ceiling joists. If you don't do that, you will be jacking the roof and jacking down the ceiling joists. Twice the energy used to move half the load, half the distance and you'll wind up with a bowed ceiling. Methodically start jacking up the ridge and using 2x4s as temporary posts holding every thing in place. Then add Collar Ties. There's going to be a lot of stress on them so I would install them at every rafter or every other. Still, that won't transfer the load to the foundation. It will just strengthen the roof structure. Then I would run purlins across (stack 2 2x4s?) the ceiling joists from the top plate of the load bearing wall to the other side. Then build a knee wall on top of it. I don't think kink posts will be necessary.Or, don't do the knee wall and just do the King posts but that will be tricky because you have your temporary jacks in the same place. Those boards running across the joists (purlins) will need to rest on the load bearing wall at each end. You will probably have to poke a couple holes in the left side of the garage to run those long purlins in.

I've inspected a roof exactly like this. I could see the dip pulling in the driveway. Fortunately, it had no ceiling in the garage so the fix was easy.

You say the walls haven't moved. Something is moving somewhere. It's either the walls or the rafters have broken loose from the wall plates and they're sliding along the top plate. There's no way a roof can sag and not move something unless the rafter boards are so compressed that they have shrunk and I doubt that happened.

[Snipe Hunter]

I feel like making that roof go back up and the walls inward is not going to happen that easily.  Seems that to winch it inward, you would probably need many winches and a way to spread the load along the wall.  And the roof angle is rather low, so it's not going to want to go up easily.  Jacking the center beam seems like the best start.

OTOH, your walls have nothing keeping them out or in, so they might move back into place if you jack up the ridge beam.  

I am thinking that it would be prudent to put in collar ties at the current location just to avoid catastrophic failure.  That puts an actual repair off for a while. Around here, that roof would be gone by now due to snow load.

Winches are a dangerous way to do it. Support the ceiling with temporary posts and jack up the roof. That way, the load is always transferred to the foundation. If something "gives" using a winch, it could be a very bad day.

[Mr_Mike]

Still, that won't transfer the load to the foundation. It will just strengthen the roof structure.

Collar ties will transfer the vertical load to the walls, and thus to the foundation. Not a big fan of it, but it works. (Heck, its transferring load to the foundation right now.) I'm way not interested in doing that in a built structure like the OP has. In this case, I like de-skinning and starting over. But, since he says he would like to make a two story addition in place of the garage, I now say "Do nothing". It doesn't leak, its apparently structurally sound enough, and doing work right now does him no good.

[Cooler]

Collar ties will transfer the vertical load to the walls, and thus to the foundation. Not a big fan of it, but it works.  (Heck, its transferring load to the foundation right now.)  I'm way not interested in doing that in a built structure like the OP has.  In this case, I like de-skinning and starting over.  But, since he says he would like to make a two story addition in place of the garage, I now say "Do nothing".  It doesn't leak, its apparently structurally sound enough, and doing work right now does him no good.

As long as he does not live in the snow belt, fine.  

My perspective (snowy upstate NY) might be different from someone living in California.  And I have no idea where the subject house is located.  But if it needs a new roof any time soon I would remove the old shingles before adding the weight of another layer.

[EricU]

virtually all the load goes to the outside walls right now.  Not much of it is making it to the gable walls. OP doesn't have his location set, but anywhere on the east coast north of Atlanta probably gets an occasional ice storm that will put a load on that roof that might fold the whole thing.  There's already a 10 degree gap between the joists and the ridge beams.  OP doesn't want that to get bigger. That's why I suggested collar ties.  Granted, jacking the ridge beam wouldn't be much more work, but when it's back to where it started, collar ties are the way to go.

Obviously, ripping off the roof and putting in trusses is a better idea, it's a bit much though.

[Mr_Mike]

Its already been though a few winters. Is it really going to get worse in the next two years? I'm going to risk it and if it falls in, see how much home owners insurance will cover.

Apparently this was not brought up in the home inspection as an issue either. So, its not considered a big deal.

[MKepke]

the walls are still straight remarkably.  So i'm guessing the rafters slid on the walls instead of pushing them out.

Its already been though a few winters. Is it really going to get worse in the next two years? I'm going to risk it and if it falls in, see how much home owners insurance will cover.

Apparently this was not brought up in the home inspection as an issue either. So, its not considered a big deal.

I disagree. The OP thinks this was pretty recent construction - in the last couple of years. I think it could get worse.

I would jack the ridge and pull in the walls simultaneously. Like others I suspect the walls have bowed.

I would consider installing a ridge beam as a jacking beam and plan to permanently install it after jacking.

The walls can be brought in (ideally) with heavy duty turnbuckles and chains. Those don't become hazards under tension. Those aren't readily available tho (you probably need to fab them), so I'd consider using heavy duty ratchet straps, say 6-8 of the 3500# working load type - only because jacking the ridge board should be taking most of the load.

I'd move everything in/up a little bit at a time and give the framing time to adjust.

I'd overlift the ridge by ~1/2" or so (assuming it'll sag slightly under its own weight), then permanently install the ridge beam with bearing to soil.

http://www.log-cabin-connection.com/stru...-beam.html

The downside is that a 20+' ridge beam is going to be neither cheap nor easy to manhandle. But cheap is how your garage got where it is now.

-Mark

[Cooler]

Its already been though a few winters.  Is it really going to get worse in the next two years?  I'm going to risk it and if it falls in, see how much home owners insurance will cover.  

Apparently this was not brought up in the home inspection as an issue either.  So, its not considered a big deal.

I had my house inspected by a big name national company (probably a franchise), and he missed a lot.  The biggest was the fact that the basement flooded when it rained.  And I asked him specifically to look for that.  It only cost $4,000.00 to have the leak addressed so not a big deal, but it eroded my confidence in home inspectors.

My electrician told me that he was brought in to address some electrical issues on a house that had been recently bought (and inspected).  The house was wired entirely with aluminum, but the last 6" of each wall outlet was re-wired with copper to give the appearance that it was a copper wired house.  

So I don't know that having a house inspector overlook an issue is that much of a confidence builder.  

As to whether it will get worse.  Absolutely it will.  Unless something is done to prevent it.  How much worse depends (I would guess) primarily on the weather.  But if there are 3 or more layers of roofing on the garage, the immutable laws of gravity will have its way gradually, annually and inevitably.

[Large Wooden Badger]

Sorry again, I was out of the office yesterday at a conference.

The house is in Texas - snow is of no issue.

The garage was added two years ago, when the rest of the house was remodeled.

The inspector certainly noted it, but I had already told him I was aware of it, and took $20,000 off my offer price because of it.

My plan is to pull down the really nicely done sheet rocked ceiling, and start by jacking up the ridge.  Once that is back where it should be, I'll see what the rest of it does and go from there. Then I'll add the collar ties and purlins and any other support and we should be good.

Discovered the retired gentleman across the street was in the trade and has some major jacks etc that I am welcome to use, that should prove to be helpful.