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Thread: Concrete under stanchions ?

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    Concrete under stanchions ?

    Anyone able to give advice on what mix I should order for bases for bolt-down stanchions please ? 40ft span. 18ft to the eaves. As far as I know it is not a sulphate area. Thanks for any help.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by zaza View Post
    Anyone able to give advice on what mix I should order for bases for bolt-down stanchions please ? 40ft span. 18ft to the eaves. As far as I know it is not a sulphate area. Thanks for any help.
    If it's the pads for the steel legs, the last shed we did we used 30N. We poured in 200mm then steel mesh then the rest 400mm.
    According to our builder all pads are 600mm deep. One of our sheds is 45ft wide and the pads are 1mtr by 1mtr by 600mm deep.
    I think we told the ready mix company what we was doing and they sent a foundation mix, maybe more stones in it compared to say a mix for a floor. Good-luck, i do love seeing a new shed go up it interesting to see how its all done.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by loon View Post
    If it's the pads for the steel legs, the last shed we did we used 30N. We poured in 200mm then steel mesh then the rest 400mm.
    According to our builder all pads are 600mm deep. One of our sheds is 45ft wide and the pads are 1mtr by 1mtr by 600mm deep.
    I think we told the ready mix company what we was doing and they sent a foundation mix, maybe more stones in it compared to say a mix for a floor. Good-luck, i do love seeing a new shed go up it interesting to see how its all done.
    Thanks for that. I have never gone less that 1m x 1m x1m for stanchions. Might do gable posts a bit smaller but a bit of a faff to change buckets. Must admit I've never heard of mesh in stanchion pads before. This new shed isn't going anywhere at the moment. Green field site and although all ready for digging and dropping the muck in on Monday we had 15mm of rain last night and it is still persisting down.

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    Re: Concrete under stanchions ?

    Don't know where you are but up here most of ours and I've seen the neighbors foundations all go in at 600mm deep. And yes the gable posts usually go in smaller, but i suppose at all down to ground conditions. A neighbor has a shed built on made up ground and his pads are massive.

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    Re: Concrete under stanchions ?

    1m 1 m 1 m work out 1 cube of concrete dont know why people skimp over foundation that's what holds up the shed

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    Re: Concrete under stanchions ?

    i put up buildings for a living and on virgin ground 600x600x600 deep, c30 concrete, no need for mesh as how are you going to push in the bolts, and even if you drill holes and chem fix in the bolts afterwards the drills don`t like metal !!!.

    regards

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    Re: Concrete under stanchions ?

    Quote Originally Posted by HotBed View Post
    i put up buildings for a living and on virgin ground 600x600x600 deep, c30 concrete, no need for mesh as how are you going to push in the bolts, and even if you drill holes and chem fix in the bolts afterwards the drills don`t like metal !!!.

    regards
    Thanks for that. I have done a bit of investigation on the mix and it appears to be a bit of a minefield. Is a C30 mix good enough ? The people I am talking to (Hanson, Lafarge, etc) are all talking RC30/35/40

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    Re: Concrete under stanchions ?

    when i did my shed, i was working out how concrete i would need. so i thought 6 post, 6 holes 1mx1mx1m =6m3. thought if i halved the numbers it would mean i needed 3m3. ie. 500mmx500mmx500mm=3m3. this is very far off.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by Dave View Post
    1m 1 m 1 m work out 1 cube of concrete dont know why people skimp over foundation that's what holds up the shed
    600mm of concrete in the base, then stantion on top, then about another 400mm ish off concrete to hold the shed down and bring concrete up to floor height or base of floor pad height will give you your 1m3. Putting 1 meter in depth under the pad is unnecessary unless you need to go deep to get onto good ground. If you want to go ott with the pads you are probably better increasing the footprint (eg 1.3 x 1.3 x .7 concete depth) so the weight is spread over a bigger area.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by diggerjones View Post
    when i did my shed, i was working out how concrete i would need. so i thought 6 post, 6 holes 1mx1mx1m =6m3. thought if i halved the numbers it would mean i needed 3m3. ie. 500mmx500mmx500mm=3m3. this is very far off.
    500x500x500 x6 posts is 3/4 of a cubic meter.

    1m x 1m x 50cm x6 posts is 3 cubic meters.

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    Re: Concrete under stanchions ?

    thats right. at the time i could'n get my head round it. 500mmx500mmx500mm = 1/8m3 x 6 = 3/4m3. think this is right.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by HotBed View Post
    i put up buildings for a living and on virgin ground 600x600x600 deep, c30 concrete, no need for mesh as how are you going to push in the bolts, and even if you drill holes and chem fix in the bolts afterwards the drills don`t like metal !!!.

    regards
    If the pad 600mm deep, 200mm of concrete, then mesh, then 400mm of concrete, then push the bolts in. The bolt should be 350-400mm max so even with the threads out of the concrete there's only 250-300mm in the concrete so they wouldn't even touch the mesh.

  13. #13

    Re: Concrete under stanchions ?

    What use is the mesh then? You don't need it.

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    Re: Concrete under stanchions ?

    Surely a lot depends what soil type you are on? Our sheds are 140ft (20ft bays) x 80ft span, 30ft to the eaves and have 1 cube under each post, on heavy clay. Mesh is a waste of time and money.
    Was JD Andrew before we were reincarnated......

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    Re: Concrete under stanchions ?

    Quote Originally Posted by no land farmer View Post
    What use is the mesh then? You don't need it.
    If you are putting a concrete floor in, the mesh is then used to tie in with the mesh in the floor or depending on your design and use/ground conditions, you would use it to tie in with a ringbeam.
    Hope this helps.

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    Re: Concrete under stanchions ?

    Need abit of advice on this !.

    my shed 100x50x16 works out the most economical way to make the legs is to use a 15.5m beam to make 3 legs, but it will only leave enough for 300mm to concrete in on top of the foundation pad. Is 300mm enough concreted in ?, the foundation pads will be 1mx1mx700mm with 4 375mm holding down bolts set into it. The leg base plate is 500mm square and then 300mm concreted up to floor level to make up the 1m cube.

    just to add its a machine shed come workshop.

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    Re: Concrete under stanchions ?

    A well designed farm building will be secure without being bolted down at all let alone concreted in, it will depend on what sideloads you intend putting on it after that.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by 4wd View Post
    A well designed farm building will be secure without being bolted down at all let alone concreted in, it will depend on what sideloads you intend putting on it after that.
    Sideloads as in concrete panels and grain storage ?. If so there won't be any it's purely for machine storage and workshop.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by Hesston4860s View Post
    Need abit of advice on this !.

    my shed 100x50x16 works out the most economical way to make the legs is to use a 15.5m beam to make 3 legs, but it will only leave enough for 300mm to concrete in on top of the foundation pad. Is 300mm enough concreted in ?, the foundation pads will be 1mx1mx700mm with 4 375mm holding down bolts set into it. The leg base plate is 500mm square and then 300mm concreted up to floor level to make up the 1m cube.

    just to add its a machine shed come workshop.
    300mm on top of foundation pads sounds like overkill to me. After all you'll not be driving on them. I'd be happy with 150mm enough to hide the bolts and bring it up level. The walls will hold stanchions in place even if the concrete around the base plates lifts and the bolts into the pads fail. If a storm comes that does that sort of damage there isn't going to be much left to bolt down anyway.

    Ps if mesh is being put in pads to tie floor too as suggested what depth of concrete is going in the floor??

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    Re: Concrete under stanchions ?

    Quote Originally Posted by Hesston4860s View Post
    Need abit of advice on this !.

    my shed 100x50x16 works out the most economical way to make the legs is to use a 15.5m beam to make 3 legs, but it will only leave enough for 300mm to concrete in on top of the foundation pad. Is 300mm enough concreted in ?, the foundation pads will be 1mx1mx700mm with 4 375mm holding down bolts set into it. The leg base plate is 500mm square and then 300mm concreted up to floor level to make up the 1m cube.

    just to add its a machine shed come workshop.
    The sheds I mentioned above:

    Quote Originally Posted by Andrew View Post
    Surely a lot depends what soil type you are on? Our sheds are 140ft (20ft bays) x 80ft span, 30ft to the eaves and have 1 cube under each post, on heavy clay. Mesh is a waste of time and money.
    Have no concrete on top of the bolts at all, both of them have been there for 7-8 years now and haven't taken off yet. If you're having a 150mm concrete floor then thats all you need on top of the posts in my opinion.
    Was JD Andrew before we were reincarnated......

  21. #21

    Re: Concrete under stanchions ?

    Quote Originally Posted by Hesston4860s View Post
    Need abit of advice on this !.

    my shed 100x50x16 works out the most economical way to make the legs is to use a 15.5m beam to make 3 legs, but it will only leave enough for 300mm to concrete in on top of the foundation pad. Is 300mm enough concreted in ?, the foundation pads will be 1mx1mx700mm with 4 375mm holding down bolts set into it. The leg base plate is 500mm square and then 300mm concreted up to floor level to make up the 1m cube.

    just to add its a machine shed come workshop.
    You dont 'need' any concrete on top of the column baseplate for the foundations to work. The pad foundation should be designed to work as it is cast with the holding down bolts in it. The concrete cover on top is just that, a cover. It protects the baseplate and bolts and also allows the floor to be taken to the perimeter of the building.

    Ask whoever is doing your shed or founds to see the foundation calc sheet and it will show you that the design is done with the column bolted down to the bolts, with no concrete over.

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    Re: Concrete under stanchions ?

    Quote Originally Posted by no land farmer View Post
    Ask whoever is doing your shed or founds to see the foundation calc sheet and it will show you that the design is done with the column bolted down to the bolts, with no concrete over.
    Theres no one to ask ! I'm doing it all myself.

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    Re: Concrete under stanchions ?

    I was told that the foundations are more for keeping the shed down when its windy, obviously also needed for side loads, but a shed should just sit where its set. Overhangs act as an umbrella effect and need big foundations. We have done a few sheds in the last few years and the one with the smallest pads is the widest building and the one with the biggest pads is the narrowest (half the width of the biggest one) but has a big overhang on one side.

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    Re: Concrete under stanchions ?

    I know everyone sais you don't need concrete over the pads, but when its blowing a force ten gale its nice to have a few concrete walls holding things down with rebar welded to the steel. when the wind starts to really blow I wouldn't like to guess the pressures on everything, our shed at home sometimes shudders in the wind and it has walls all the way around it!

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