Shed foundations...

[Hard-Drive]

Time to turn to the wisdom of PH for advice on that most British of traditions, the garden shed!

Need to put up my bargain basement B&Q shed (so I can carry on the development of my fusion cooled gamma ray rotary wankel drive teleportation system of course) and the shed will need some kind of hard standing. It will be an odd shape, 15' x 6', and will be on a bit of waste ground in my garden.

What's the best way to lay the foundations? Not sure I fancy laying lots of paving slabs and trying to get them level, can I just get some wooden planks, stood on their sides and staked in place and make a bit of a self-levelling "mould" and pour concrete in?

If so, roughly how much/what depth concrete do I need, do I need a concrete mixer, and where's the best place to get it? Or will it just be too expensive and will the paving slabs be a better bet?

[Egbert Nobacon]

If it's level ground just get four concrete fence posts, lay them down and stand shed on them - job done.

[spikeyhead]

I went for the paving slab approach.

Once I'd done it I wished I'd done concrete.

[evenflow]

NB: I am not an expert.

Dig out a level-ish area the size of the base of the shed. Put a layer of hardcore and rubble over it - 2 or 3 inches maybe, as flat as possbile. I reckon a few inches of concrete would be enough on top of this. Mix 4:1 sand:cement. You wouldn't necessarily need a mixer but would be hard work mixing in a barrow.

[Mark.H]

Are your neighbours tts? cos if they are id think twice about laying foundations as it means its a permanent fixed structure and that means you need planning permission for it. If they take a disliking to you you could be made to take it down.

Edited by Mark.H on Thursday 23 October 10:12

[Davi]

Hard-Drive said:

What's the best way to lay the foundations? Not sure I fancy laying lots of paving slabs and trying to get them level, can I just get some wooden planks, stood on their sides and staked in place and make a bit of a self-levelling "mould" and pour concrete in?

Yes.

couple of inches of hardcore in the base, "a few" inches of concrete on top of that. Depends how durable you want it to be and what you are planning on doing in there as to how thick it needs to be, some will tell you 6 inches min, some will tell you 3 inches.

glad to see I'm not the only one that measures concrete thickness with "a few inches".

Edited by Davi on Thursday 23 October 10:14

[evenflow]

Davi said:

Hard-Drive said:

What's the best way to lay the foundations? Not sure I fancy laying lots of paving slabs and trying to get them level, can I just get some wooden planks, stood on their sides and staked in place and make a bit of a self-levelling "mould" and pour concrete in?

Yes.

couple of inches of hardcore in the base, "a few" inches of concrete on top of that. Depends how durable you want it to be and what you are planning on doing in there as to how thick it needs to be, some will tell you 6 inches min, some will tell you 3 inches.

glad to see I'm not the only one that measures concrete thickness with "a few inches".

Edited by Davi on Thursday 23 October 10:14

Did you see my "NB:" ?

[sleep envy]

Mark.H said:

Are your neighbours tts? cos if they are id think twice about laying foundations as it means its a permanent fixed structure and that means you need planning permission for it. If they take a disliking to you you could be made to take it down.

Not true - I live in a conservation area and regardless of the base a shed of less than 10m3 doesn't need PP.

OP - if you fancy a sinking shed use slabs or posts (preferbaly concrete as timber does tend to rot.

If you want to make sure the shed doesn't go anywhere strip the turf and topsoil down 12", get some hardcore or MOT type 2 (a couple of inches will be fine and then pour in a good concrete mix (with reinforcement bar if you are feeling particularly belt and braces). A mix of 4:1:1 will be fine.

You can get it delivered pre mixed if you fancy saving your back but if not hire a mixer, I screeded my house (80m2) and that took me and 2 other blokes 2 days to do with a mixer.

[tom g]

I used concrete fence posts, on top of strong polythene. perpendicular to the joists of course!

You could cut them to length with an angle grinder.

Bonuses:
allows circulation underneath -> no rot
easy to level up by putting packers underneath the posts

[catso]

evenflow said:

few inches of concrete would be enough on top of this. Mix 4:1 sand:cement.

You'll need some ballast (gravel) in there, otherwise you're just making cement (as per bricklaying) which will crack - you should be able to get the right stuff ready mixed from builders merchant or large DIY store, just add cement & water.

[Hollow Legs]

I used a thing called HawkLoc. (www.hawklok.co.uk)

You dig out your base area then put this stuff down. Its a bit like big lego pieces that you just slot together to form the base.

Much easier and less messy than concerete. Can also be removed/moved if you ever want to move your shed & hence get around the potential permanent fixture issue.

[evenflow]

catso said:

evenflow said:

few inches of concrete would be enough on top of this. Mix 4:1 sand:cement.

You'll need some ballast (gravel) in there, otherwise you're just making cement (as per bricklaying) which will crack - you should be able to get the right stuff ready mixed from builders merchant or large DIY store, just add cement & water.

Ah yes.

[Mark.H]

sleep envy said:

Mark.H said:

Are your neighbours tts? cos if they are id think twice about laying foundations as it means its a permanent fixed structure and that means you need planning permission for it. If they take a disliking to you you could be made to take it down.

Not true - I live in a conservation area and regardless of the base a shed of less than 10m3 doesn't need PP.

OP - if you fancy a sinking shed use slabs or posts (preferbaly concrete as timber does tend to rot.

If you want to make sure the shed doesn't go anywhere strip the turf and topsoil down 12", get some hardcore or MOT type 2 (a couple of inches will be fine and then pour in a good concrete mix (with reinforcement bar if you are feeling particularly belt and braces). A mix of 4:1:1 will be fine.

You can get it delivered pre mixed if you fancy saving your back but if not hire a mixer, I screeded my house (80m2) and that took me and 2 other blokes 2 days to do with a mixer.

but using the size he said it is its 8m2 (assuming he quoted in feet cos otherwise he has a BIG shed) and im assuming its a reasonable 2m high thats 16m3???

Edited by Mark.H on Thursday 23 October 10:28

[sleep envy]

Mark.H said:

but using the size he said it is its 8m2 (assuming he quoted in feet cos otherwise he has a BIG shed and im assuming its a reasonable 2m high thats 16m3???

correect, 10m3 is the limit in my area but his council planning offce will have a different threshold

my point was (possibly put accross badly) it has nothing to do with the base but more to do with the volume of the structure

[Mark.H]

sleep envy said:

Mark.H said:

but using the size he said it is its 8m2 (assuming he quoted in feet cos otherwise he has a BIG shed and im assuming its a reasonable 2m high thats 16m3???

correect, 10m3 is the limit in my area but his council planning offce will have a different threshold

my point was (possibly put accross badly) it has nothing to do with the base but more to do with the volume of the structure

• RULES

• You can put up a building in your garden without planning permission if it is less than four metres high, is less than 50 per cent of the area of the house, and is at least five metres from the house.

• You will need planning permission if your house is listed, in a conservation area, or in an AOB (Area of Outstanding Beauty) unless the building you want to erect is less than 10 cubic metres.

i think we're getting away from the point, MR OP, please double check this before you do it to avoid future problems.

Edited by Mark.H on Thursday 23 October 10:39

[Mr POD]

Paving slabs from the free ads. Use them whole or break them into hard core.

[TheGreatSoprendo]

The way I did this last year was to:

• Bang in timber pegs at each corner, and level off using lengths of 2 x 1 and a spirit level (you want the base slightly higher than the surrounding land to avoid waterlogging, and therefore rotting, the base of your shed).

• Nail lengths of timber between the pegs as shuttering which will contain the concrete.

• Put in a hardcore base, then fill with concrete.

• Wait until dry, remove pegs and shuttering, et voila!

I'd thoroughly recommend using a mixer. They're cheap to hire, you'll only need it for a day and it'll save you a hell of a lot of backache (mixing concrete by hand is no fun at all).

[Swilly]

For a 15'x 6' garden shed just put down about 4 inches of gravel, put shed on top...

You dont need concrete bleeding foundations !! jeezus

[Corpulent Tosser]

If the ground s fairly sound - that is not marshland - I would and have just put down 4x4 posts, leveled them, put some felt over them to prevent damp and lay the shed floor on that

[unclegrouch]

+1 for the gravel idea.

I put a 14'x10' in the back garden of my last home, no base as such, just 2-3" of gravel. Moved lat year when the shed had been there for 7 years & the floor bearers were still in very good condition. I'm no expert by a long way, but imho the gravel lets any water drain away from the base, a concrete pad could hold water ?