Shed foundations help

[ss]

Re built my shed and it will be 9 x 5 feet will only be used for storage as later on will add a roofed canopy for any work. I have started to dig out (on a slight slope, previoulsy badly slabbed) With the bits and pieces I have had to buy I cant afford to rent a whacker or much else to complete the job. I have for foundations 20mm chips (approx ton), 25kilo cement powder and a ton of sharp sand. I was intending digging down about 9 inches and building up with chips etc but finding it a bit heavy going (heart issues) I have managed about 6 inches of dig out and was thinking of maybe digging a bit deeper for some say 6 inch square concrete foundations (pillar), one in each corner and say one in the middle, this would mean less digging out, then level all this with:-

3 inch layer of 20mm chips, then using a weak mix to bring up to the top of the concrete pillars. The shed would then sit on this, then 2 x 2 wood on the foundations and then the shed floor on top of this. Is this likely to be suitable foundations for my shed? Whats best way to whack down the 20mm chips manually? As I said budget now spent so have to manage as best I can.

[Phil L]

That's a lean mix

When you say you've dug six inches, do you mean you've took a 9X5 foot by six inches deep off? If you have, I'd be tempted to just fill it with sand and stone mixed, then rake the bag of cement all over (you may need another 1 or 2) mix it insitu with the rake and tread down fairly flat. You can pack up your 2X2's off this to get the level you require.

[ss]

"Thats a lean mix" thats the materials I have at hand not necessarily the final mix.

Yes, my idea was 1st 3 inches loose then next 3 inches a mix. You reckon I need more cement powder? 9`x5` x 6" deep. Only other thing I would mention is the underlying soil/clay is fairly compact.

[John Rumm]

What sort of soil conditions?

If free of roots etc then you can probably get away without going mad on it.

That would be a weak mix ;-)

2' length of 4x2" and a sledge hammer. Stand on either end of plank, drop hammer onto the middle a few times, then kick it along a bit and repeat.

[ss]

The top couple of inches were pebble/ sand on which were laid paving slabs, the next 4 inches or so are a kind of clay/soil mix quite compact and slightly `sticky` and no vegetation. I have been taking out the layers trying not to disturb `underneath` so it remains compacted as much as possible.

[ss]

Preferably after dinner when I weigh more :-)

[Phil L]

Right. Firstly, you don't want loose chippings under concrete, as chippings / pebbles / stones etc don't pack down so the concrete would break up.

Knock a wooden stick into the ground in each corner. Attach stringline to one and run it to the corner diagonal to it and test it for level, it only needs to be a few inches thick for a shed. Do same with the other two corners, making sure the second string is touching the first at the point they cross over. Once all your strings are level in all directions, knock in a few more sticks here and there, near to or touching the strings. Mark all sticks with white paint where they touch the string, remove all strings and concrete to the white markings.

An easier and quicker method is to make a timber frame and concrete inside it once it's levelled up, but from your earlier posts, I assume there's no money left for timber.

[ss]

That sounds like a good way for me to do it. I should have enough timber from previous jobs and bits of scrap I havent disposed of yet.

[Phil L]

Just make sure it's level in all directions, then peg it inside and out to prevent distortion./ And don't try to mix concrete manually if you have a heart condition - seriously, it's nothing like mixing sand and cement or plaster

[Nightjar]

Google MOT Type 1 and see if that is what it is.

Colin Bignell

[John Rumm]

Indeed - its hard work with a mixer!