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Cabinetmaker/Gen construction
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Discussion Starter · #1 ·
Hi all,

New to the forum, thanks for having me here.

I'm working to solve some sagging rafters on a garage/woodshop. It's double gabled with 12/9 pitched roof and 32x24 footprint. I'll add some pictures here.

The issue the rafter ties were raised at some point to a little less than a third the rafter length, and ties were drywalled and attic insulated. There had been storage up there as well but that has been removed. The are a handful of hangers/struts in the attic to keep the rafter ties turned ceiling joists from sagging.

The result is some very saggy rafters. To solve this, i'd like to add beams under each end of the rafter ties - either right at the joint with the rafter or slightly inboard, and jack up the rafter ties/rafters to remove the sag. Then place posts under the beam, either 3 or 4. The fewest i can get away with using a reasonably sized beam. The beam will likely be butt jointed over the posts for easier handling.

I'd to remove the crooked hangers from the attic and replace with more vertical hangers to keep the rafter ties/ceiling joints from dropping too far in between the beams. My thinking is that that wouldn't cause too much undo stress on the roof considering the new beams are taking the load off the ends, and allow the center of the shop to remain free of posts.

The first question is if you all think that's a workable solution.

If not, any suggestions? I'd rather not involve an engineer if i can simply overbuild this enough. The budget is low.

If so, i'm curious about the sizing of the beams. My assumption is since they will be lifting the rafters, they should be sized for roof/snow load, versus just for the rafter tie/drywall dead load?

Thanks again for any advice or opinions.
 

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Designer/Contractor
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"If not, any suggestions? I'd rather not involve an engineer if i can simply overbuild this enough. The budget is low."

The best money spent would be on the services of a competent engineer or architect who can do engineering and yes, they do exist.
 

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Pro
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That looks like an absolute mess.

The rafters are undersized. You need trusses, a crap ton of localized support, multiple beams spanning both sides of the roof system, or new rafters and a ridge beam.

Many solutions, but need a pro to do this.

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Shingler extraordinaire
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Hi all,

New to the forum, thanks for having me here.

I'm working to solve some sagging rafters on a garage/woodshop. It's double gabled with 12/9 pitched roof and 32x24 footprint. I'll add some pictures here.

The issue the rafter ties were raised at some point to a little less than a third the rafter length, and ties were drywalled and attic insulated. There had been storage up there as well but that has been removed. The are a handful of hangers/struts in the attic to keep the rafter ties turned ceiling joists from sagging.

The result is some very saggy rafters. To solve this, i'd like to add beams under each end of the rafter ties - either right at the joint with the rafter or slightly inboard, and jack up the rafter ties/rafters to remove the sag. Then place posts under the beam, either 3 or 4. The fewest i can get away with using a reasonably sized beam. The beam will likely be butt jointed over the posts for easier handling.

I'd to remove the crooked hangers from the attic and replace with more vertical hangers to keep the rafter ties/ceiling joints from dropping too far in between the beams. My thinking is that that wouldn't cause too much undo stress on the roof considering the new beams are taking the load off the ends, and allow the center of the shop to remain free of posts.

The first question is if you all think that's a workable solution.

If not, any suggestions? I'd rather not involve an engineer if i can simply overbuild this enough. The budget is low.

If so, i'm curious about the sizing of the beams. My assumption is since they will be lifting the rafters, they should be sized for roof/snow load, versus just for the rafter tie/drywall dead load?

Thanks again for any advice or opinions.
You should be more worried about your shingles starting to curl up.

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Cabinetmaker/Gen construction
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Discussion Starter · #8 ·
lol, that's a good variety of opinions, i can work with that.

best money spent would be on the services of a competent engineer or architect who can do engineering and yes, they do exist.
An architect is who originally steered me towards two beams on either side of the ceiling. We did not get into specifics on loads and beam sizes, but i'll go ahead and bring someone else in. You're obviously all correct, that's the best money that can often be spent.

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You should be more worried about your shingles starting to curl up.
I am indeed worried about that. I figured I should solve the framing concerns first though before adding the new roof.

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From your pictures, I just don't see enough wrong with the roof and ceiling to warrant putting much work into either of them.

The rafters are undersized. You need trusses, a crap ton of localized support, multiple beams spanning both sides of the roof system,
That's the spread of opinions i've gotten before from various contractors and framers i work with, which lead me to the compromise of beams on either side, either 3 or 4 posts depending on beam sizing and load.

When you say i need trusses - are you talking building truss elements into the existing space? Part of my thoughts are to add king posts and struts up there once the sides of the ceiling are supported, rather than whatever you'd call what's up the now.



All that said, I'll just go ahead and bring in someone local to engineer this for me, i'm obviously out of my element with this. I'd be still curious to hear more about your thoughts however if you wanted.

Thanks for your time.
 

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Goin' Down in Flames....
Highwayman
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First off, what’s your level of expertise? It says cabinet maker. How much experience do you have with framing?

Elaborate a little on what you mean by roof sagging. Is it sagging in the middle? Are the walls bowing out?

What are those kickers on the outside of the building?

You realize that any solution is going to necessitate the removal of the ceiling drywall and insulation?

At that point, you might look into just pulling the roof and installing trusses, or a structural ridge like META suggested. 👍
 

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Pro
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That's the spread of opinions i've gotten before from various contractors and framers i work with, which lead me to the compromise of beams on either side, either 3 or 4 posts depending on beam sizing and load.

When you say i need trusses - are you talking building truss elements into the existing space? Part of my thoughts are to add king posts and struts up there once the sides of the ceiling are supported, rather than whatever you'd call what's up the now. .
When I say trusses, I mean adding webbing and gussets onto the ceiling joists to rafters to form trusses, built into place. That would require some specialized engineering and probably not your best option.

The rafters could be sistered with material rated for the span, with a ridge beam to carry their load, or you need collar ties....but that will interfere with your existing ceiling.


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I think you will have a tough time pulling any sag out of it. I'm on my phone and can't even see any.

I'm on the it doesn't look bad enough to worry about.

Maybe just strap, shim and level a metal roof on and be done if it bothers you.

Sister some new rafters in.

Easy is better. It hasn't fell down so far.

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Discussion Starter · #12 ·
I think you will have a tough time pulling any sag out of it. I'm on my phone and can't even see any.

I'm on the it doesn't look bad enough to worry about.

Maybe just strap, shim and level a metal roof on and be done if it bothers you.

Sister some new rafters in.

Easy is better. It hasn't fell down so far.
There's a fair amount of sag, maybe my pictures don't show it adequately. I have to get up there and measure it but it's likely an inch or even more in the middle.

I'm not concerned about the look of it, i just don't want it to get worse and risk rafter failure.

That leads me to a couple beams at the sides to take the excess loads off the rafters, jacked up to remove any sag i reasonably can. That would obviously wreak havok on my drywall, but i'm not concerned about the aesthetics. This is my own shop and i'll repair as much as needed. I'd cut an opening for the beams so i'm not crushing drywall underneath it.

Maybe the truss building in the attic would cause more issues with the added weight in the roof than any good it might do?

If i need to level the roof for metal i can do that - my plan is to just go metal on top of shingles anyway when i'm ready.


First off, what’s your level of expertise? It says cabinet maker. How much experience do you have with framing?

Elaborate a little on what you mean by roof sagging. Is it sagging in the middle? Are the walls bowing out?

What are those kickers on the outside of the building?
I'm a cabinetmaker (8 years-ish) with only very limited framing experience. Most of my advice on this has come from framers and GC's i work with. They'll help me do it.

The walls are fairly plum still, and the ridge is fairly straight. The rafters are sagging the in the middle to lower third, where the ties are connected.

Those kickers are supporting the extended eaves i added long ago. I extended the eaves about 24" to help keep water away from the building.
 

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Design Build
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Maybe actual purlins down to beams. All the info you need is in the IRC code book for rafter spans under prescriptive loads.

Those individual 2 x 4 legs that are nailed to the side of random rafters is doing nothing because the nails are dealing with the vertical load in sheer direction.
Purlins would span across all the bottom edges of the rafters, but you'd need to have them land on beams above your ceiling joists to not transfer any roof loads to your open ceiling area.

Wood Rectangle Engineering Beam Composite material


I do overkill on the purlin bracing mostly because attics get hot and lumber tends to twist as it is baked.
 
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Doesn't look that bad from the pics.
I'd be inclined to go all (as in gut the attic and sister
2x12s onto the existing rafters, then install cross-ties
on top of the wall where they belong) or nothing.
 

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Discussion Starter · #15 ·
Thats good help, thanks all for the advice. Any additional comments are appreciated, but I'll get the advice of a local arch/engineer, make a plan and let you all know how it goes.
 

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I agree with purlins as a possible fix if you are saying that the roof is low in the middle. It means straightening each and every rafter as you add the purlins (with a jack, usually the force applied 90 degrees to the rafter and you need to have a method of finding what straight is, easier done with the shingles off). You usually need a way to brace the purlins at not over 45 degree angle to the rafter and the braces have to transfer the load to the ground. This is hard to do in an open span garage.
I have seen an alternative, usually done when being built, but possible could be retrofitted. A boxed purlin system at mid span of the rafters all the way around the inside of the roof can be built. The box is made of structural beams and the entire purlin beam is attached to the next beam as well as every rafter. I hope I explained it well.
If I recall that is a system used in England a lot. This would require an engineer stamp and some real thought as to how to lift the beams into place and straighten the rafters as you install it.
 

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Shingler extraordinaire
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There's a fair amount of sag, maybe my pictures don't show it adequately. I have to get up there and measure it but it's likely an inch or even more in the middle.

I'm not concerned about the look of it, i just don't want it to get worse and risk rafter failure.

That leads me to a couple beams at the sides to take the excess loads off the rafters, jacked up to remove any sag i reasonably can. That would obviously wreak havok on my drywall, but i'm not concerned about the aesthetics. This is my own shop and i'll repair as much as needed. I'd cut an opening for the beams so i'm not crushing drywall underneath it.

Maybe the truss building in the attic would cause more issues with the added weight in the roof than any good it might do?

If i need to level the roof for metal i can do that - my plan is to just go metal on top of shingles anyway when i'm ready.




I'm a cabinetmaker (8 years-ish) with only very limited framing experience. Most of my advice on this has come from framers and GC's i work with. They'll help me do it.

The walls are fairly plum still, and the ridge is fairly straight. The rafters are sagging the in the middle to lower third, where the ties are connected.

Those kickers are supporting the extended eaves i added long ago. I extended the eaves about 24" to help keep water away from the building.
What we are telling you is that your roof framing is decent.....your shingles on the other hand are not.

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Demo
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Sounds like you're going to spend either a fortune or nothing. It hasn't fallen down yet. If and when it caves in you can frame a proper roof with your insurance money. Once you start pulling at this thread your wallet's going to unravel.
 

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Shingler extraordinaire
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At most a stiffback and some beefy screws

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