Levelling a shed base

[petek]

We're having a largish shed built at our golf club to store our golf buggie s (3 of them). The base is concrete, 8.6m x 2.0m.

Unfortunately the concrete base is not level (I won't bore you with the rea sons why!)One corner is approx 50mm lower than the others which is preventi ng us from erecting the shed itself and getting it square. I'm thinking of laying a further layer of concrete on top of the existing concrete, say abo ut 25mm thick, which would taper to 75mm thick in the low corner IYSWIM. Is this feasible? Does it need any bonding between the existing surface and t he new concrete?

TIA Pete

[Tim Watts]

Yes and you will need SBR for this (because you are going thin at one end):

The PDF there has everything you need.

Another question: Do you need the floor level or just the shed frame? If so can you

a) Stand the frame on Wallbarn adjustable stands

b) As the screed, but just run a wall of it around teh edge to mount the frame on.

[sm_jamieson]

If the shed can be a little taller, lay a very low dwarf wall round the edge to support the frame ? Might also help to protect the frame if it is timber.

Simon.

[Adrian]

We've just had exactly this with an outbuilding floor. Unfortunately for us, ours needed to go up ~75mm at one corner - but 0mm at the diagonal opposite.

If it was all at least 20mm+, it'd be an easy screed, I was assured. Thinner than that, there's a risk of it breaking up.

Prep was apparently no more than a bloody good clean up, then PVA and sand to give a key. Can't hurt to go over the surface with something like a grinder to score for a key, though.

[Adrian]

Should add that we went for the nuclear option. Break it all up, get it all out (two guys, 1.5 days (but could easily have been one), stihl saw and road-breaker drill), new plastic, and re-lay. It looks lovely now, but...

[Brian-Gaff]

Doing the latter for a greenhouse has resulted in a lot of break up of the smallish pile of concrete over time, presumably from water and frost and the puddling effect due to the slope of the original concrete it was built on, so I'd have reservations about how long it might last. My feeling might be to build it on something substantial like some wooden beams with them levelled by using some wood cutting, and use a floor inside the shed made of wood. Of course one needsto retreat the wood where its been cut. Brian