Saving an English Bank Barn (Collapsing Foundation)

[Sinoed09]

Thanks for the add to these forums!    I have a sad but common problem - my barn is slowly collapsing. :( I bought a farm with a heritage bank barn probably built around 1870-1880 that was sorely neglected by the previous owner.  The bank wall has collapsed and one of the sill beams has cracked due to overloading (there is straw still left in the mow).  The timber frame is gorgeous, hand hewn beams some 40' long and 10-12" wide and it has a good roof so it's in good shape.  Looking at old barn boards 18-24" wide, the thought of tearing it down just makes me want to throw up.

The barn is roughly 40x80 and 3 of 4 walls are failing.  Although the bank wall is the worst, the other walls are leaning in, leaning out and/or slowly separating- I can't save them.  My plan right now is to put cribbing under the beams as an emergency stabilization measure, empty the mow, jack the barn level, knock out the wall in sections, pour a new concrete footer, build a block wall on the inside half and re-use some stone to build an exterior shell in keeping with the original look.  It's a massive undertaking.

What I don't know is how to calculate the load / stress on the structure to size the new concrete footings.  I'm an engineer so the math doesn't scare me but I don't know where to start (or even look).  The beams are huge and heavy, not to mention the volume of hay that could be stored and the snow load (I'm near Owen Sound, Ontario).

I checked out the barnitall site, the Ontario barn preservation and I've been looking for structural engineering books but they typically deal with sizing newer materials.  I'm sure some will say I should hire an engineer, but having spent 4+ years getting my degree I want to dig into it myself.

Does anyone have any info or links on how to size the footings? ???  I'd like to give this barn another hundred years or so.

[Jim_Rogers]

To size a footing you're going to have to know what load it is to support. You'll need to measure the timbers in the structure to get a boardfoot total. And then using that number find the estimated lbs per bdft. Add at least 10 or 15 lbs for roof sheathing/materials. As well as wall sheathing loads. This should get you the dead load.  Hay doesn't weigh much per sqft, but you may need to add that if you intend to continue to store hay in this barn.

Then add the snow load. This will give you the entire structure's total combined load. Then you're going to need to figure out what part of that load each footing is carrying.

Next knowing what the footing is carrying you're going to have to know what the soil conditions can support. You may need to have a soil analyst done.

If you check with local foundation companies they may have some knowledge of your area's soil conditions/support abilities.

You can try and find a restoration company near you and see if they can give you any advice, about the soil conditions in your area.

Good luck with your project.

Jim Rogers.
PS please fill out your profile so we know where you are or where the barn is.

[Iwawoodwork]

I second Jim Rogers request to let us know what area your barn/ you reside in, there may be members close by who have experience and can help.

[Don P]

Hay and grain storage is 300psf design load I believe. I seriously doubt you will hit that use but it won't hurt anything to foot for that.

Roof is snow load + dead load, you won't be wrong at 15psf on the horizontal projection, (plan view).
Vertical and horizontal planes are around 10 psf

[Sinoed09]

Jim - thank you for simplifying the process.  It doesn’t need to be overly complicated and I think the straightforward approach is great.  

Iwawoodwork - I edited my profile to add the location (Owen Sound, Ontario) and I took some photos today while investigating.   I’m not sure if anyone is up this way but if they are and want to reach out feel free.

Don - Thanks for the extra insight into the load of materials.

The original barn was about 40x50 and at some point a 20’ extension was added to the west side.  The extension is covered with green siding in the overview photo.  The original barn isn’t in bad shape, the extension is the part that’s failing badly.  The floor in this part is supported by 12” logs spaced about 44” apart.  Half of these have one end placed on top of the original foundation wall which is a solid 2’ thick and quite stable, unfortunately the opposite end was supported by the collapsing wall.  I got lucky since at least half the north part of the floor is also supported by an additional cross beam 2/3 of the way to the exterior wall.  The extra beam runs under these logs which has helped to keep the north corner standing.  I think the best strategy will be to use this extra beam to my advantage as the safest place to start.  I’ll get some cribbing into this section and then work my way into the bad corner.

I can’t completely tell what logs were used, it looks like it might be a mix of hickory, ash and birch.  I really don’t know what the hewn timbers upstairs are.  I guess for safety’s sake I can just assume the heaviest log type and go from there.

It’s probably hard to see in the photos but if you look at the ground it’s pretty easy to see why this happened.  There is a solid 4-5” of ice on the floor which has been slowly breaking apart the walls.


 

 

 

 

 

 

 

 
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[Don P]

Basement's already dug and the rocks are on site, easy peasy ;D.

Looking at the lack of weaving in what I'm seeing of the walls and what fell out, it could have been tougher. It wouldn't hurt to work some steel reinforcement in there both ways.

You should be able to rotate those pics in your gallery.

[Sinoed09]

Basement's already dug and the rocks are on site, easy peasy ;D.

Haha right? :D I will say the rock wall crumbling and the mess downstairs doesn't bother me that much. But thinking about hand forking out the mow makes me sweat - I never did like haying.  There is zero chance of any equipment getting onto that area so I might have to find some labourers for cash.  That's one job I'm not looking forward to at all! :-\
Fixed my pics so you don't have to look sideways. 

[Don P]

I'd bet you can stick the boom of a Lull in the gable end upstairs. If the rental yard has a bucket for one and if you have decent approach to the end it looks like the height is about right to shoot the boom right in. Even forking into a big work basket or a homemade pallet/box chained to the forks would speed it up.

[fluidpowerpro]

Just looking at the pics, considering everything else, the amount of hay left in that barn isnt amounting to squat as far as weight. I wouldnt let that stop you from starting work.
As far as how deep the footings need to be. How deep are they now? The barn has lasted 100 ++ years using the original design, so I would use them as a guide and go a little deeper for insurance.

[Don P]

By the looks of things, not only deeper, wider too! It's easy to point to masonry 20 times older done by unwilling workers. For a stone wall it died young. It looks like someone did try to buttress it in 2 places? 

Take some width measurements at the tie, figure out the design dimensions of the building vs what you have. I can't tell if the foundation wall tops are leaning out or if the bottoms have been pushed in by roof water and frost. If the interior posts are out of plumb, I cant tell if that is camera distortion or if its that tilted, but do install and X brace good plumb shoring and temporary beams under there. Make sure it can't fall into the basement.

The assumption: As you move and grind, be prepared for the stone to collapse. Have a known, braced, load path to ground.

[Jim_Rogers]

To make a stack of cribbing blocks use 6x7 timbers. Stack them with the 7" dimension up.
Then when you need to add a short bottle jack you can put in some pieces 6" tall for the jack to stand on:



 

Also for bracing:



 

Good luck and work safe.

Jim Rogers

[Sinoed09]

Don - I think you're probably right about the height to pull out the loose hay.  The siding on the end isn't worth saving anyways and that would probably work really well.

As far as the wall goes - I have sections that are leaning out at the top in the old section of the barn, sections that are collapsing in where the addition is and some parts that seem okay.  Looking around the property there was a lot of concrete work done (maybe in the 50's?) to install a cow trough, a few outbuildings and I suspect to pour the now destroyed barn floor.  I think the barn was having a few issues at that point - there is sloped concrete to direct water away from the sill beams all around the foundation.  I think that's when those strange buttresses were put in.  They've actually done a pretty decent job of shoring up that section and enough that I can save that part of the wall for after the emergency repairs are done.  Some of the posts in the old section are out by about a foot at the top but that's mostly due to the wall collapsing on them.

Fluid- Right now I don't know how deep the foundations actually are - I haven't done much digging or poking to figure that part out.  The original walls are 2' thick so I'm assuming they're fairly deep but I really don't know.  I'll have to measure depth when I start taking them down.  The barn is perched on the Niagara Escarpment so I'm wondering if I'll just hit rock.

I started documenting and taking some measurements of the beams last night as per Jim's outline.  The larger beans are hand hewn 11"x11" - there don't seem to be any saw blade marks on them that I've found (yet) just axe/adze marks.

Jim - I've got my eye on some 6x6 Timbers for cribbing, they go on the auction block this weekend.  That diagram is quite helpful.

I did read that the length of the cribbing pieces needs to be at minimum 1/3 the height of the eventual stack for safety.  I currently have 74" under the logs so minimum 3' sections will be what I need.  I also read that the stacks shouldn't be out more than 30 degrees so I might build a couple temporary pads with self levelling concrete.

One question about bracing the wall.  I expect the stone to fall - if it falls outside that's not a big deal, if it falls inside it could bounce into my cribbing.  What's the best way to brace the stone?  Posts on a 45 degree angle?

[Sinoed09]

Since this thread already has photos of the barn, rather than start a new one I'll just add to this one.  I called around to a few different places and a local sawmill but large enough beams for cribbing are all custom cut, special order and pretty pricey.  I went the auction route instead and bought skids of lumber to start my project. ;D

Everything I bought is all rough pine which doesn't have the breaking strength of something like oak but it's available and affordable (relatively speaking).  Based on my research, a 6x6 post cribbing tower can support ~20,000lbs, a 4x4 can only support 8,000 so I chose 6x6 as it seems to be the safer of those two options.

In terms of size, the length of each board has to be a minimum of 1/3 the total stack height for safety. Right now I have 74" from the floor to the bottom of the logs which means each piece of my cribbing needs to be at least 25" long.  Since the barn is out by a lot, I'm going to be cutting my cribbing into lengths that are 36" long which should give me plenty of room for jacking and to keep it safe.  To get enough height with 6x6 posts I will need 12 pieces on each layer, 2 pieces per layer for a total of 24 pieces or 72 linear feet per stack.  I also bought 6x8" posts that I will use by turning them sideways to create a jack platform as shown in the pic by Jim.

I have a dozen 6"x8"x12' beams that I'm going to use to spread the weight between the stacks and carry the load down.  I will probably use 2 beams over two stacks to support the weight of 3 logs.  Each log based on the calculators here is about 800lbs, I'm still working on sketching out the frame to design the footers but I think the load of the logs plus floor & roof will be fine.

I'm also going to use some of the 6x6 posts to brace the stone wall from the inside to prevent a collapse into my cribbing.

Before I do any actual jacking I have to do a thorough inspection upstairs.  The tenons are pulling out of at least one roof column on the rear wall and one of the tie beams is arched upwards like a bowstring due to pressure.  I'm thinking about securing the posts with wire cable to keep it together in addition to cross bracing.

I'm going to look at a small electric winch for dragging the larger posts into position - even in pine they're pretty heavy.

It will probably be a couple weeks before I'm able to really tackle this but the plan right now is to build cribs and get emergency stabilization in place.  Once it's stabilized I need to empty the mow, cross brace and then slowly jack it to deal with the foundation.  Major project.. but new wood always makes me happy. 😁

I'll post a couple pics of my haul when I get to my computer, my iPad doesn't like adding photos from the gallery.

[Iwawoodwork]

I really like it that you are trying to save that old barn, to many people let them deteriorate then destroy them and replace with a pole building covered with tin, functional yes but no character.  I hope that you have been able to get it stabilized.   Any more updates and photos of your progress would be appreciated. This renovation would make a great youtube video with a time lapse from start to finish.