Leaning wood Quonset help

Hey all,
Not sure if this is the right place to post this but here it goes.

Me and my wife recently purchased an achreage and there is a 45ft by 85ft wood Quonset on the property that's leaning pretty good towards the rear endwall. I'm planning on straightening it myself and wondering if anyone has any good insight on how to go about it and more importantly how to make it stay.

My plan so far is to screw two large boards on either side of the peak line across 6 or so rafters with and eye hook on the end and use 14,000lb 1/4 cable and a cum along cement anchored at the other end of the building and pull it straight. My paranoia is weather or not 1/4 cable is enough and might snap, or will the board screwed to several rafters not let those rafters move enough to come straight or worse will they not support the rest of the weightand rip the rafters out.

As for how to secure it once it's straight, I'm completely lost. I regularly see quonsets with boards running from bottom middle to upper corners in the peak to keep them straight but I have no idea how to make the wood bend in such a manner or where to get it. I thought of using cable but the I think it is 1/4 cable enough again or how do i tie it to each individual rafter and still be able to tension it.

Any help is greatly appreciated.

Thanks in advance,
Bob

Hi Bob, welcome to permies!  I don't know for sure how to fix your leaning quonset but I have a few questions that may help other folks understand the issue better.  What kind of sheeting or skin is on the quonset hut?  How tilted is the building?  Are there any other major components to the building (attic, loft, walls, ect)?  Could you attach a few pictures?  That would really help.

I'm assuming you would be attaching the two boards at the rear end of the building and then setting up the come-along at the front end so that as you pull on the boards, they push the rest of the building up straight?  

My initial, uninformed thought is that the weak link of the plan are the eye bolts.  I'd want to make absolutely sure they couldn't strip out or rip out the ends of the boards.  If they fail or the cable snaps when you have the building halfway righted, my guess is it would spring back and keep on going till it's flat on the ground.  Be very careful when you're doing this job

Thanks Mike!

It's a concrete floor and foundation, steel roof with wood lap length wise bare inside and it's leaning pretty bad.

I had the same thought on the eyebolts, I'm planning on supporting it from the leaning side with a front loader and some 4x4's just not sure how I'll keep tension against them.

More pics

Wow, that's a big building.  Not sure why I didn't think 45x85 wouldn't be huge.  Is that roof fairly new?  I'm not sure you'd be able to pull it up (or down) as long as the roof steel is attached.  

I'm going to stop offering suggestions cuz this is way out of my league.  Hopefully some of the knowledgeable folks can give you some guidance

I does seem to give a larger appearance especially inside. I used to work in a 40 by 65 shop that seems like and out house compared to being in the Quonset and the measurements I gave are going off of what the inspection reported so I may have to measure it myself one of these days just to be sure.

I hadn't thought of the roof tin being an issue. It is newer and I was told by the neighbor that the Quonset was roofed with the lean, but there are visible wrinkles in the tin and even a few screws popped loose. I am wondering if I may be able to undo all of the screws except for the ones along the peak and straighten it and just reinstall them once straight? I'm sure I'll have some finish tin to do but I'll be re building the endwalls anyway so it probably wouldn't hurt to order a sheet or two of green with all the other supplies.

Wow.....can I trade "problem buildings" with you!  --->  https://permies.com/t/49023/ft-quonset-roof-sagging-middle

Disclaimer:  What I'm about to suggest is not from the fingertips of a structural or any other (useful) kind of engineer.  To me, it looks like the "lean" is the only problem.  Your ridgeline looks good as does your foundation and ribs.  Even if the roof is showing some age and wear, re-roofing can do wonders these days.

Are the long support posts within the building anchored in the cement?  If they are, this is where I would design the "cross supports" to keep the building square once you've pulled it back to true.  As for pulling it back to true, your idea sounds feasible, even though I can't recommend which thickness of steel cable to use.  I will recommend NOT using lag-type eye screws....use eye-bolts that you can put a nut on the end of.  Drill through the beams that you wish to attach these to and then secure on the back side with a bolt + good size washer and possibly other pieces of wood to *ensure* that the bolt will not pull through.  I may be wrong, but I'm thinking that perhaps less force than you imagine may be needed to pull the building back to true since the ribs and the inner support beams are all still pretty upright.  [You can just leave the bolts in place and paint over or cover them.....will keep the holes filled and give you something to grab onto if you wish to airlift the building to a new location..........   ...kidding ]

Once it's pulled true, I would fabricate long diagonals to run from the top of one of the inner support beams down to the foot of one of the other support beams.....probably not the most adjacent one since that wouldn't provide as much support I'm thinking.  

I'll leave it there for the time being.  Let me know if you want a drawing for the supports.  Good luck!

Robert Kruppiak wrote:I was told by the neighbor that the Quonset was roofed with the lean, but there are visible wrinkles in the tin and even a few screws popped loose. I am wondering if I may be able to undo all of the screws except for the ones along the peak and straighten it and just reinstall them once straight?

I had suspected they reroofed it with the lean.  The roofing is probably helping prevent further lean to a degree.  I'm pretty sure that if you pull on the building a little, you'll take the wrinkles out of the tin and it will be leaning just as much as when the previous owner roofed it.  If you pull a bit more you'll add new wrinkles in the opposite direction.  If you pull it up straight the roofing will rip off or do something irretrievable.  

My guess is that if you pull all the screws except the topmost ones, a breeze will come up and blow them all over the place.  I have no experience with doing this, but I would give some thought to removing all the screws except for the middle row going the full length of the roof panels.  Then the sheets will be held down and I'd think that they could shift as needed when you pull the building straight.  I'm assuming the roof tin is the kind where one side overlaps the hump of its neighbor (see pics below).  You may get a bit of "overseat" or "underseat" as they call it in the second picture but it probably wouldn't be much.  Then once it's straightened the tin can be just screwed back down and you may not have to cut any off or do patches.  Many of the screws would try to follow their old holes in the wood sheathing.

Just out of curiosity, how much lean is in the building>  Have you measured it?  It would be easy to see using a plumb bob, Don't think I would trust just a level with something that tall.  Is the lean consistent all the way through from one end to the other?  

I'm not an engineer by a long shot, but I figure that your roofing will need to be removedcompletely before any straightening can be done unless you want to ruin that metal.  If/when you get it back plumb I would highly suggest getting some diagonal braces on it to help keep it from moving again.

Off topic, but man, what I wouldn't give to have a shop building that size.  

I would strongly advise a few things:

1. Contact some professionals to get their opinion on straightening the building. It never hurts to get a quote, and they might have different strategies.

2. If you plan on using a cable, get something way stronger and use multiple cables at once. 14k lbs isn't that strong for something that size, and if you're not using a remote winch and the cable snaps — that's a very scary proposition. For reference, that building very roughly experiences that level of wind load at ~70mph, meaning it might take more than that to right it (the building is almost definitely designed to sustain higher winds). You want cables 2-10x stronger than you need for safety, and preferably remote control or some kind of protective structure

3. Really think about finding a way to push, using some heavy machinery, or hiring this out. Heavy loads, hand winches, and cables make for horrifying mistakes.

That being said, I really don't know what kind of force it would take to straighten it out. It depends tremendously on the roof sheathing (sheathing is what give buildings their shearing strength). What I do know is that cable snapping mistakes are ones people usually don't walk away from.

I will measure the lean and the actual dimensions of the Quonset tomorrow hopefully.

I had thought of pushing it with some 4x4's and  my truck but i was thinking I wanted to have a slower more controlled way of pushing it. I think it has plenty of power and weight but it is a manual and I didn't want any chance of over doing it. Although maybe if I measure the lean I can build a stop at the appropriate distance on the other side.

I'm still scratching my head on how to brace it from leaning once it's straight. Or how to brace it without interfering with the space below or the loft I plan to put in in the future.


Wow.....can I trade "problem buildings" with you!  --->  https://permies.com/t/49023/ft-quonset-roof-sagging-middle

That looks a lot harder than what I'm dealing with. I'm terrified with just the lean. I do have more than the one problem building unfortunately though. The site was abandoned for five years and time was not kind to any of the buildings. The Quonset is just my first headache, although the chicken coupe might just get knocked down before the Quonset gets fixed but that should be fun.

The bracing option I'd pursue is to just get a bunch of 2x6s and screw them to the undersides of the joists at a 45 degree or flatter angle to the joists.  Screw into every joist that the brace encounters.  The curve of the roof/wall is probably shallow enough when you angle the braces that the 2x6s can follow the bend.  Another option is 1x6s which will certainly bend enough.  Here's a very crude sketch.  You can run them towards the lean or away from it.  I'd probably orient it so that the braces would be in tension if the building tries to lean again.  The longer the brace boards are the better (fewer joints).  Overlap the ends of the braces so that they share two joists.  There is probably a metal bracing option that would work similarly to this.

I like Mike Jay's bracing idea. I might even go with two rows of 2x4 diagonals per side, spaced 10' or so apart, to reduce the point load on each rib.

I might also build in compressive bracing in a similar manner, but angled in the opposite direction, by cutting lengths of 2x4 or 2x6 to fit between the ribs at a 45 degree angle or whatever is appropriate, with angled ends to sit flat on the ribs, and screwed into each rib. With each brace aligned with the ends of its neighbors, the leaning force would be carried by these braces without stressing the original ribs. It would also take no space from the interior.

I think that relieving the lean just enough to remove the roofing wrinkles, and a little bit more because the structure will relax a little when the straightening cables are removed, would be the simplest path by far. Adding enough bracing to take the lean load into the future would probably be far cheaper than unbuilding the structure enough to totally undo the lean.

Well this weekend I tried to straighten the Quonset and realized how little I understood the structure. I have had cables on it for weeks with frequent tightening and no luck and so this weekend I tried everything I could think of. We removed all of the screws from the tin secured four points to the front of the building to pull from which we tried using the winch on my truck with a bobcat for an anchor the bobcat, my little frieghtliner we had a lull pushing from behind once pulling from the back rafters from inside, we removed every bit of bracing we could see and nothing. At one point we got two inches of lean out of it and put braces in and as soon as we let pressure off the machines it settled right back where it was. I can't think of anything more I can do short of tearing it apart. And I'm not able to use it as is due to the insurance company is not willing to insure it or anything inside it as long as it leans. I think the Quonset may be at an end if I can't come up with a solution.

How about trying some other insurance companies?  I've found they vary greatly in what they consider a risk and what they could care less about.

I'd get some steel flat bar, 2 pieces, something like 1/2" thick 6" wide by 6 feet long, drill a big hole in the middle (7/8"?), and numerous smaller holes around the perimeter.

get a lift to get you up near the peak of the back, and secure one bar across the back as high as you can go with the bar horizontal.  Repeat at the front.  

drill through the big hole of the steel, through the end wall, and put an 3/4" EYE bolt through it from the inside, and secure it with nuts and lockwashers.  Both ends.

I would use an electric winch with heavier cable...   say 3/8" and tie rope pieces along it every 10 feet or so, in the event it breaks, the ropes absorb the energy...   and nearest they winch, use a HEAVY blanket.

for bracing, I'd use 1x4s long pieces and anchor them along the ribs at a 45* angle, with the high ends at the front/back.   like a multi sided V...   \\\\\\\\///////   Use multiple levels to reach near the peak.


now, with a BMF turnbuckle connected to one of the 3/4" eyebolts run some 1/2" cable between theturnbuckle, and the opposite eyebolt, and secure the ends of the cable loops with proper cable clamps.  

use the turnbuckle to put some tension on the cable, just enough to make it feel snug, not to much so as to pull your walls in and break the wall studs.

This will support the ends from lean from a windside force and a Leeside force.

Also, if you have 2" lumber, perhaps look at putting some support along the ribs to give strength for the side to side lean.  some 10' 2x4s attached inside the curve of the ribs in a few places.



that is what I would do, as a layman, if it were mine.

You do what you think is best.

Is it just the fact that it is not perfectly vertical, or that it is in danger of falling, that the insurance company has a problem with? If they are reasonable, reinforcing the frame so that it is as strongly braced as the original is leaning should take care of it. If they are afraid of the out-of-plumb framing, I would second the advice to investigate other insurance companies. Several rows of 45 degree compression bracing forced and nailed into place would make it actually safe, and a PE should be able to inspect it and satisfy a decent insurance company. If you unfastened most of the roofing, I would think the wrinkles should be gone.

No one is really going to like my answer here, but insurance is typically based up percentage of claims, in this case percentage of claims based on design.

We had a dealer that sold these type of builders here, but being from Maine where we get a substantial amount of snow, all have collapsed. They just cannot handle the weight, wind loads, etc and I see that in this building. I do a lot of work at a kids camp and their gym was build of this design, and during the summer the basket ball hoop height was NBA height, and with a snow load in the winter we could reach up and touch the rim flat footed...that is signs of a collapsing roof. Kids were playing in the building just hours before that building collapsed. With your building, it is obviously collapsing otherwise the previous owners would not have tried to shore up the structure with vertical posts. It is an arched truss type roof, it should be an open span. The fact that the end wall is blowing out (leaning) is just further signs of of its eventual demise.

At this point I think your best alternative is to salvage the steel roofing, salvage what lumber you can, and then rebuild upon the foundation. The sooner you do this, the better; before all you have left is twisted metal and splintered wood.

Please accept my apologies for such a dire prediction and suggestion. Trust me, I salvage as many buildings as I can, and have moved a pile of them to save them; but this building design is just poor.