Sagging Roof Insight

[CLETUS]

Base on this pic... I'd try jacking up the ridge board. (You need to support the attic floor from below while you do it.) Then add in collar ties on the rafters. Also, I'm wondering if you're lacking rafter ties on the outside walls. I'm not a builder but I'm leaning toward shoddy construction. However, I think my idea is the best way to cobble it together.

[Large Wooden Badger]

There is no code enforcement of any kind, its a rural lake, I can't tell if they anchored the rafters until I get up in it, but I'm guessing not as it doesn't appear the walls have bowed, so I'm guessing they just slipped.

I think if I get the ridge straightened out and add some extra bracing it will be fine.

[Cooler]

In the middle photo you can see the 2 x 8 roof rafters are not snug to the ridge beam.  I did not know what they were called until I looked it up but the term shown is "collar tie".  

You will have to draw in the sides with a winch to get the rafters to snug up against the ridge beam.  After you pull them in you can add the collar ties.  Use heavy nails (not screws) for this--they have much more shear strength than screws.  You will probably have to winch in each rafter as you work your way across the ridge.  But you want to get all the joints back in their original position before you add the collars.  

If you have more than two layers of roofing over the garage you may want to rip that off first.  And before you have any other problems you might want to add the collar ties to the main house structure.  

If any of the ceiling joists have been cut that could also add to the problem.

[Mr_Mike]

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.

[Large Wooden Badger]

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

[Large Wooden Badger]

So how would you draw them in to attach the collar ties?

Add a couple of blocks to each side of the rafter, drill a hole through them for a cable and and use a come along to winch them back together?

Or is that overkill, just drill a hole and use a come along?

[Turner52]

What Mr Mike said. If your walls are not bowed out, then it was constructed that way. 40 + years in the trades. Nothing to keep the walls from spreading. Way wrong.Pull a string line on front and back walls. Ithink you will be suprised.

[Mr_Mike]

The cable and come-along pulling either the walls or the rafters would be the way, I reckon. I'm not much for crawling around in attics though. Certainly string the walls as even an inch of bow may not be noticeable.

Pull in the center and work back each way I would expect.

But, here is a plan...Do nothing. It ain't getting worse.

Worst case plan. Wait 'til next dry season and tear off the roof an put up trusses.

[Large Wooden Badger]

as near as I can tell, this is only about 2 years old, so I'm not sure it isn't getting worse.

I don't want to invest a whole lot in it at this point, as if we decide to move into this in a year when my youngest graduates high school, (about 45 minutes away from where we live now), then I'll tear it off and put on a major garage with second story, like six stalls, three for garage and three for shop with a big game room above overlooking the lake.

[Cooler]

Amazon sells manual winches.  You don't need an electric winch because you are only going to move the walls an inch or two, so not much cranking involved.

I don't have a clue as to the amount of poundage you require for this.  Amazon has both 1,000 and 1,500 pound versions.  The 1,500 pound version is about $185.00; the 1,000 pound is about 1/2 that.  

You might be able to rent one, but then you'd be under pressure to get things done really quick.