base for new shed

[Witchy]

Hi folks,

Typical for me to be doing an outdoor job just as it starts getting cold but hey ho.

Having built a small 6x4' shed I've discovered the ground isn't level enough for it to stand on - there's a drop of max 45mm from corner to corner so I've decided to use some spare paving slabs we've got to make a proper level playing field for it.

None of the diy stuff I've read considers building a platform on uneven concrete, they all assume a shed goes in a garden and advise on turf removal/ground preparation etc.

Is it worth slabbing for such a small drop, and if so how much sand/cement will I need to make a dry mix for the slabs to sit on?

-- cheers,

witchy/binarydinosaurs

[robgraham]

You imply that your shed is sitting on the soil. I would have thought that it would be better to have it up on slabs of some sort, or on a concrete foundation. If you do this you could level it up at the same time. You'd probably get away without any snand/cement if you levelled the soil reasonably first.

Rob Graham

[Bob Mannix]

It's not worth it while you are doing it (!) but afterwards when you look at it it's well worth it. I use 6:1 sand/cement to lay the slabs on and 3:1 brushed into the gaps a while afterwards and gently watered as grouting.

[Witchy]

Hi Rob,

I can guess you speed-read my post :) What I said was:

This hopefully gives the impression I'm trying to build on uneven concrete......

I'm after either reasons to slab or not to slab, and in particular the volume of sand/cement I'll need to lay said slabs.

-- cheers,

witchy/binarydinosaurs

[robgraham]

Yes, I must have done!

Rob

[robgraham]

Is there any reason why you can't level the shed with some wedges and push cement under the walls?

Rob Graham (speed reader)

[Rick Hughes]

scrape it flat within an 1" .. then put down a nice bed of sand ... if you are buying it buy sharp sand not builders sand. Screed it over with a batten or plank so it is level.

Then put your slabs on that - rock them back and forth top bed them in ... job done.

[Witchy]

Hi Rick,

I'm still not sure if slabbing the area isn't overkill as it's already concrete and such a small drop. I'm getting very tempted to just batch up some concrete and pour it into a wooden frame, then I won't get a weed problem and will only have to heft the shed up 45mm instead of over a sandbed and thick paving slabs! Idleness :)

I've also got no means of cutting the slabs.....

-- cheers,

witchy/binarydinosaurs

[Witchy]

Hi Bob,

Ta for that, but I think you're right about overkill. Yesterday we thought about building a timber frame for it to sit on (I've got tanalised joists left over from another project), and last night wondered about making a concrete bed because then I'll end up with having to heft the shed up only 45mm instead of several inches - one of the issues is that the shed is already built and very undismantleable......

-- cheers,

witchy/binarydinosaurs

[John Ormiston]

We have building sheds and bases for over 25 years unless the ground is very soft we don't recommend concrete for a base. The water that gets under the floor (and it will) has no way to escape so the floor joists end up sitting in a puddle for long periods of time. Better to lay gravel or hard-core which will allow drainage.

So in this case where the concrete is at a slope will aid in drainage I would then "level" with support bearers and shims to build up from.

[robgraham]

In the light of the above why not lift the shed up on wedges and put cement in under the walls about 2" deep to keep the wood off the floor? This will level it as well.

Rob Graham

[Witchy]

Thanks for that John,

That's what the Missus wanted to do! The shed building instructions say use paving slabs, and bits of me think I might as well go with a concrete base since the construction of the shed panels themselves make me think it's not going to last longer than a few years, if that, so joists sitting in water won't be a problem :)

The term that springs to mind is 'friday afternoon construction' for those of us that remember the friday afternoon cars that BL used to put out in the 70s!

-- cheers,

witchy/binarydinosaurs