Shed foundation

xxedrushxx

Hey all
Went to replace a 6x8 shed and found this uneven mess underneath. What's the best way to create an even foundation. I was thinking either a wood frame with wedges to level it out or relay concrete over the top. Not sure if it's ok to lay wood directly on concrete like that or for concrete, whether it's ok to lay concrete on concrete 

Rosa_Damascena

I've just had a shed base laid down onto grass. The area was cleared first, a timber frame laid and then concrete poured. Looking at it now, I don't think its any taller than 400mm.

Soot2006

Jet wash it, infill the cracks with mortar and then a thin scree of concrete. For a shed base that should be fine.

grumbler

Or this can be several concrete slabs laid on 'dots' of mortar. In this case it's worth levelling the slabs with some packers/spacers first.

xxedrushxx

Thanks for the ideas. I didnt think about using paving slabs either. Do you think its possible to create a level foundation using dry mix first and then plonk the slabs on top after a bit of sprinkled water? 

FreeBear

Having laid a whole bunch of slabs last year. by far the easiest was with a wet mix. Use a soft sand (8 to 10 parts sand, one of cement), put down a generous layer (~25mm thick), and gently bed the slab down on it. Use a soft (rubber) mallet and you shouldn't crack the slab..

That said, I'd be more inclined to put a strip of timber down each side and get them level with each other. A couple of 2x1 battens would do the job. Then put a layer of screed down (sharp sand/cement mixed 6:1) using the battens as a guide. Would probably work out cheaper than buying a pile of slabs, and quicker too.

xxedrushxx

FreeBear said:

Having laid a whole bunch of slabs last year. by far the easiest was with a wet mix. Use a soft sand (8 to 10 parts sand, one of cement), put down a generous layer (~25mm thick), and gently bed the slab down on it. Use a soft (rubber) mallet and you shouldn't crack the slab..

That said, I'd be more inclined to put a strip of timber down each side and get them level with each other. A couple of 2x1 battens would do the job. Then put a layer of screed down (sharp sand/cement mixed 6:1) using the battens as a guide. Would probably work out cheaper than buying a pile of slabs, and quicker too.

Thanks for the suggestions. I dont have the confidence to do the screed, plus I saw that if its done wrong it will crack. So, I think I'll try the paving slabs, with wooden batons across and then a big wood sheet over the top. 

FreeBear

xxedrushxx said: I dont have the confidence to do the screed, plus I saw that if its done wrong it will crack.

It doesn't matter in the slightest if the screed develops a few cracks. It is only there to level off the surface and transfer/spread the load of the shed. Maybe, if the shed didn't have its own floor, a crack in the screed might be an issue, but it would only be a cosmetic one.