Removing barn loft reinforcing

[mtaves]

I have a 30'x50' barn with a 30' high loft I have finally cleared of pigeons and all their leavings. I want to turn it into a usable space, but bracing inside really limits the practical floor space. The end wall bracing I will leave, but there is a brace mid-way on the roof down to the floor that I need to remove. I have seen numerous barns in my area that have collapsed, where the building had this same profile (although they were much longer) so want to make sure I don't screw up a loft that is currently in pretty decent shape. I have included two pictures to give a sense of the geometry/size. You can see the brace is bowing a little, which tells me there has been some (but not much) sagging in the middle already. I would appreciate any feedback/ideas on what to do as an alternate bracing to allow me to safely remove this brace. I have 2 ideas so far:

1: add cross cabling 10-12' off the floor
2: add diagonal bracing between studs, the opposite way of existing bracing. The existing diagonal bracing does not give any additional support at the midpoint of the roof. Bracing high at the mid-roof point and going down towards the ends, in an inverted-V, should improve rigidity over what the current 10' long 2x4's are accomplishing.

Thanks in advance for your comments.

 

[hslogger]

Oh man what a structure. I dunno Why you figure these are a PIA for you but I want to point out one thing I do know. These barns were built to hold loose hay and so when full, they were full of loose hay and not hay bales. They were not designed for the weight and distribution of weight modern people demand in their storage desires. That in part has been one contributing factor IMHO to the demise of these structures. I will be glad to see and hear some one here who has engineering background as to pounds per square inch and external framing.

 

[Egon]

The two by fours shown probably do little to nothing in structural support.

If you can find the original design plans they should answere your questions.

Just offhand there could be more lateral bracing between the beams.

 

[mtaves]

Thanks for the quick replies!

hslogger: I realize now I didn't say what I would be using the space for. Storing hay bales is a perfectly reasonable assumption considering it is a barn loft, but I am actually planning on using it as a martial arts and dog training space for winter months when outdoor temps are not conducive to this kind of activity. Adding livestock to my acreage is in the long term plans, and have other structures with some bale storage capacity and am hoping to keep this space clear if at all possible. Floor loads should definitely stay within whatever the original design intent was.

Egon: totally agree that additional lateral bracing would really help. The way the bracing is set up, it looks like the plan was to resist bulging outward from any pressure of the loose, piled hay, rather than to resist buckling. Even if those 2x4's do almost nothing (which seems obvious now that you pointed it out), still would like to make sure this structure doesn't go the same way as neighboring barns have.

 

[BKBoiss]

Not sure if this helps you much because I was really young (7-8) but we had a large hip roof that my dad converted into a storage work shop and still kept an area for hay storage. One third was left as is for hay storage, the other two thirds he built a floor about 12 or 14 feet up I would say then another floor about 6 feet above that. That small 6 foot space we stored lumber furniture and all sorts of random junk. The top floor still left tons of room up to the ceiling and we had a little bit of a workshop and more storage up there. He ran I think two beams down the center of each floor and lined them up with the main support beams down stairs in the main part of the barn. He replaced some beam sections and most of the posts to handle the extra load and well as straiten out the barn from years of sagging. In the 6 foot crawl space he ran cable with pullers right up against the bottom of the top floor. I think it was two or three across from side to side and two diagonal from corner to corner. Like I said I was really young and this barn seemed to be hundreds of feet tall to me but maybe this will give you some ideas. All said and done the barn had four floors. The main one on ground level with the stalls the main original loft then the two new ones on top of that.

 

[Sodo]

HS I don't belive you really have a question you just wanted to post pics of your wicked loft. Of which I am insanely jealous,,,,,:thumbsup:

If those little braces are obviously holding up some sag, whats the problem with leaving them? Why not just build a closet storage on them, you can even make it a little stronger with the shear strength of plywood.

 

[Budweiser John]

First off, I AM NOT a structural engineer but from a practical point of view two 2x4s in the center of a 50' long building don't offer much in the way of structural support.
If there is a sag in the ridge line and the side walls of the building are still plumb that would indicate the " bow string" rafters are bending.
Digging back through my career as a carpenter, I recall a project involving a 100 year old church with a similar issue. Strong backs were added to the mid points of the rafter run and tie rods with turnbuckles were placed at the 1/4 points along the length of the building and running from side to side.
Save that beautiful structure.....
B John

 

[mtaves]

Sodo: I have to admit you are partially correct. It took too long to figure out how to keep pigeons out, then had to shovel out their manure which was 1ft thick in some places. Glad to finally be able to walk around up here.

To your question though: between the brace on one side, and the silly furnace room on the other side (whole other topic), the 30ft width is reduced to somewhere between 15-20ft across at this point. The martial art I practice uses longswords, spears, and staves ranging in length from 3ft to 6ft. With their reach you need to be able to get in/out of the other guys range without worrying about getting the training tool caught in a 2x4, or backing into it. It can definitely be done by restricting the sparring area to one loft end or another, but is way more fun with full access to a larger area.

 

[mtaves]

BKBois: that does help give me some other ideas of what I can do with all the extra ceiling height. Thanks for the tips!

Budweiser John: Thank you very much for the insights. I love this structure which is still remarkably intact. This is the perfect time to make sure it stays that way - before significant sag starts to set in.

 

[Jim Timber]

I'd love to see the bottom of that floor, if you'd be so kind.

 

[PILOON]

I personally would not hesitate to remove those 2 braces or whatever they are. IMO they do nothing,
If you are really concerned (maybe there is some rot there or splitting??) then cut strips of 3/4 plywood and add to both sides of the trusses in the suspect areas. Nail strips generously every 3-4 ins in a staggered pattern.

I'd be more concerned with where the trusses meet the floor. Is there rot there? could loads cause the bases to kick out or collapse under load?
On the other hand with that roof pitch I doubt that any snow loads could accumulate.
My bigger concern would be the integrity of the bases of the trusses where they meet the foundation, but that is sight unseen as perhaps they could be just fine. (like high and dry or on raised concrete foundation.)

 

[mtaves]

Jim Timber: you mean from underneath on the ground floor? Sure thing - will have to wait for tomorrow though. My camera takes real crappy pictures inside unless bolstered by natural light. Are you looking for anything in particular? My guess from looking at the grain through the pigeon dust is that it is douglas fir, tongue and groove, 4" wide. Not a wood expert though.

 

[mtaves]

Piloon: Thanks - I am glad to be getting a consensus opinion on that. There is no rot that I have found, the inside looks to always have been dry. The soffit boards are rotten in many places from having pigeon nests/carcasses on them for years but the trusses look to have escaped that damage. I always try to give the benefit of the doubt to those who came before me and probably put those in to address a specific issue, even if it does not make sense to me at first glance.

 

[fried1765]

mtaves:

What an absolutely magnificent structure you have there!
It would appear that the 2x4 braces shown are basically useless.
What does the ridge line look like (from the exterior)? Is it showing an obvious sag?
What does the soffit edge look like (from the exterior)? Straight, or bowed out?
If your soffit is bowed out, and/or the ridge line is sagging, you need to pull the building together at base of the arches.
The Romans used arch construction, and is inherently strong. Your beautiful roof will not fail if you prevent it from spreading at it's base (unless the arches are already cracked).
In Europe, steel rods with turnbuckles are used in situations similar to yours.
Without actually seeing your building, I would suggest 3/4" diameter threaded end steel rods, with turnbuckles in the center, under the floor - side to side.
You will need to make certain that the ends of the rods are solidly attached to some blocking across the the base of the arches.
I believe that one cross tie rod for every 6' of building length would do the job.
The rods will sag a bit from their own weight, so you will need to support them under the floor, but only enough to prevent sagging (concrete tie wire will work).
I have a 27' x 44' roof that I purposely built using this method, at my summer home in Nova Scotia, to eliminate a gaggle of framing that would have partially obstructed my ocean view.
I painted my cross tie rods, and the wires holding them up, a flat black, because they are intended to be seen. My building is completely open for the full height, so is quite different than yours.
You would certainly want to keep your cross tie rods below your floor. Installing cross tie rods above head height in your loft would not be at all effective!
I have a civil engineering degree, and am retired, but have never been a practicing civil or structural engineer.

 

[dieselcrawler]

Wow... awesome loft... makes our old barn loft look alot less awesome.

Unless you are stuck on keeping the vaulted ceiling look, I would concider the idea mentioned in earlier posts, of adding horizontal joist at a reasonable ceiling hight of 8 to 10 feet up, and that may suffice. Diagonal bracing to mimic a truss could be put in from them to the mid point of the rafters above in a "W" formation as well, if deemed needed.

 

[mtaves]

fried1765: more good advice - excellent and thank you very much! I haven`t looked for bows specifically but have spent a lot of time staring at the barn looking for potential problems. I have not noticed any sagging in the ridge line or bowing in the soffits, but will look specifically for that tomorrow. I have not seen any separation in the corners at the floor of the loft, or at ceiling height in the ground floor - all good there. There is some separation of the foundation under one side wall from the main slab - about 1", and from looking at movement of the wood siding one end of the barn has settled more than the other. Probably caused by frost heave. However, structurally everything in the loft looks good at this point in time. Want to make sure it stays that way. Starting to wonder if I am being overly cautious.

dieselcrawler: thank you as well. I really do want to leave the vaulted ceiling if at all possible. However, putting in a ceiling would give many other possible fringe benefits (extra storage level, easier to light and keep warm in winter). So many possibilities...

 

[Billrog]

That beautiful building is going any where any time soon looks solid as a rock. Like mentioned those 2 - 2x4's are only a token. A few suggestions are worth noting if you have concerns do to obvious structural discrepancy's you can see other wise it looks like a very sound structure.

 

[Jim Timber]

Mtaves,

I'm wondering about the support structure itself. The decking being T&G of some appreciable thickness would be my guess. The framing is what I'm curious about. It's also a beautiful arched building, so more pics of the rest of it will let us appreciate it more.

I love architecture. Balloon houses don't do anything for me anymore. I've been ruined looking at all the cool stuff they built back when being a carpenter meant something.

 

[fried1765]

dieselcrawler: thank you as well. I really do want to leave the vaulted ceiling if at all possible. However, putting in a ceiling would give many other possible fringe benefits (extra storage level, easier to light and keep warm in winter). So many possibilities...[/QUOTE]

mtaves:
Putting in a ceiling would certainly be very beneficial if you intend to use any sort of heating.
An "extra storage level" would be a BAD idea! You do not want to load those arches in the middle. Loading those arches with more weight would aggrivate the sagging/bowing that you want to avoid.
If you do put in a ceiling, make it a lightly constructed one, and store NOTHING on top of the ceiling.
In my opinion, you should be locked up for committing a crime against humanity, if you hide those magnificent bowed rafters.
Just kidding of course!

 

[PILOON]

Looking back via the follow up posts, the more I think about it, the more I suspect those 2 x 4 'braces' do nothing and probably were simply some sort of bracket for shelves or to hang something from.
That building is a dome, and domes are basically self supporting structures.