Pole barn and concrete question

[Hell Toupee]

Hi,

I've got an old barn, and one section of it I am planning on concreting and enclosing to use as a shed/chiller room etc (likely will be a 2 room set up). The section I want to enclose is about 5x5m. It has 7 wooden uprights, and several of these will need the lower sections replacing as they are rotten.

I'm struggling to get my head round a suitable way to do this. Ideally I'd like to concrete the base, then replace the bottoms of the posts and use steel brackets bolted into the concrete, rather than replacing the posts (dug into the ground) and then concreting around those. In my mind to do this would mean cutting the base of the poles off, using props to support the roof, but then I wouldn't be able to concrete the whole floor as the props will be in the way. Is there a simple solution to this that I am missing? Otherwise I can put some shuttering around the base of the props, and then fill this in with concrete at a later time, but this seems a, weaker and b, an inelegant solution.

Any tips SD?

HT

 

[kes]

Depends which way you can support what is above the wall. Iif you could use a 5m plus steel and support at either end with Acros, then you could concrete under the existing 'side' and use Metpost flat bases drilled and bolted into the new base and extend the side supports into the Metposts. A photo would be helpful, however.

Alternatively, you could attach each of the side/roofsupports to a wooden beam spanning the 5m gap (internally or externally by using a 4X8 " beam and drilling through into each side/roof support the loading would be excentric so you would have to ensure a beam and supports on both sides of the wall running 5.5 m say inside and outside parallel to the wall but close to it and bolted though it. Support these beams on Acro's again or even a temporary, well built, but not mortared, pile of bricks, if not too high, say 3-4 feet.

 

[Alantoo]

I would say it depends on the weight, strength and condition of the existing structure. Not worth knocking it down and starting again?

Are you intending to cast the concrete in one slab? If for instance you did a 2 metre wide centre strip and two @1.5 metres either side you could support a temporary post-linking/supporting rail on either side, and/or make an A-frame to support the centre section of wall and wall plate...remove the rotten posts in the centre section, cast the 2 metre strip...then make good the posts to cantilever support the rail, wall /wall plate from the new centre section and cast the side strips.

Alan

 

[kes]

The size of beam at 18" centres to hold up a floor at 5m span is 8"*2" The ones, I have suggested bolted either side of your 'wall' to the uprights should be good unless the load is huge. Sorry to mix metric and imperial.

 

[milner]

The size of beam at 18" centres to hold up a floor at 5m span is 8"*2" The ones, I have suggested bolted either side of your 'wall' to the uprights should be good unless the load is huge. Sorry to mix metric and imperial.

8x2 at 18” centres is a bit optimistic for a 5m span. I know it’s not necessarily up for building regs but they wouldn’t let you span more than 4m with it on a build
The first timber for a clear span of 5m on the tables is 10x3 at 16” centres

 

[Tim.243]

Hi,

I've got an old barn, and one section of it I am planning on concreting and enclosing to use as a shed/chiller room etc (likely will be a 2 room set up). The section I want to enclose is about 5x5m. It has 7 wooden uprights, and several of these will need the lower sections replacing as they are rotten.

I'm struggling to get my head round a suitable way to do this. Ideally I'd like to concrete the base, then replace the bottoms of the posts and use steel brackets bolted into the concrete, rather than replacing the posts (dug into the ground) and then concreting around those. In my mind to do this would mean cutting the base of the poles off, using props to support the roof, but then I wouldn't be able to concrete the whole floor as the props will be in the way. Is there a simple solution to this that I am missing? Otherwise I can put some shuttering around the base of the props, and then fill this in with concrete at a later time, but this seems a, weaker and b, an inelegant solution.

Any tips SD?

HT

Shutter around poles, set some dowles in the slab then deal with the poles after the gear has gone off.
not much different to underpinning or dowels in footing.

 

[kes]

8x2 at 18” centres is a bit optimistic for a 5m span. I know it’s not necessarily up for building regs but they wouldn’t let you span more than 4m with it on a build
The first timber for a clear span of 5m on the tables is 10x3 at 16” centres

I have suggested (Ist post) 2no 8"*4" one bolted either side of the wall timbers and bolted to them at 5m span, that should do.
You may well be correct however, so I will check thoroughly again. Thanks

 

[kes]

Just checked for standard UDL and imposed load see below - its actually nearer 9" depth so apologies for that. (220mm)

 

[User00035]

Shutter around poles, set some dowles in the slab then deal with the poles after the gear has gone off.
not much different to underpinning or dowels in footing.

This. Leave the poles in place. Prep the base and concrete round them leaving plenty of space for membrane and to allow for replacing any dirt below them with crushed stone. Prop the roof when the slab has gone off, remove the original poles, fold down the membrane and make good the holes. Or if you want to be anal you can prop next to each pole before you prep the slab, dig out any dirt under them and replace with crushed stone/type 1 and set the poles back down on that before laying the membrane.
When the slab is finished, prop the roof and fit your new posts on metal brackets.

Don't worry about the patches showing because if you're building a larder, I'd want to be painting the floor slab anyway or laying some sort of washable covering over the slab because left untreated the poured concrete will become dusty.

 

[milner]

Got

I have suggested (Ist post) 2no 8"*4" one bolted either side of the wall timbers and bolted to them at 5m span, that should do.
You may well be correct however, so I will check thoroughly again. Thanks

to be honest I didn’t read your first post, just flicked through to the end. Makes more sense now I’ve read it properly.
I had seen it was 220mm but converted to inches wrong in my head, something about men always wanting that extra inch

 

[Hell Toupee]

Perfect - thanks all.

HT

 

[Tim.243]

Perfect - thanks all.

HT

What is your plan.....take a few pictures...