Best foundation for a heavy shed?

[perky416]

Evening all.

Im getting a high security heavy duty shed for the back garden. The instructions say to fit it on a level base 3.1m x 2.5m x minimum 50mm thick.

The shed weighs almost half a ton without the contents.

In the garden where i want it to be built, there is top soil around 25cm deep, and then an old concrete slab 10cm thick (not sure if it has any rebar).

What would be the best way to build a foundation for the shed? Ive considered the following:

Hardcore and then slabs - wondering if this will be robust enough?

Pure concrete slab with rebar on top of the current one - thinking this is a bit of an overkill, costly, and heavy.

Hardcore with concrete slab on top of the current concrete slab - is it ok to put hardcore on top of concrete? Will it compress?

Any thoughts or ideas?

Thanks

 

[Alastairreid]

Can you not remove the 250mm soil from the top of the existing slab and use that?

 

[perky416]

Can you not remove the 250mm soil from the top of the existing slab and use that?

It will be below ground level then, this is how my garage is built (the current concrete slab is what the garage is built on, i want the new shed behind the garage) and it floods every time we have heavy rain. I cant keep anything valuable in there.

 

[Alastairreid]

Easiest way would be to lay a course of blocks and backfill with hardcore and concrete. If you are using that as the floor incorporate a Dpm.

 

[noseall]

The shed weighs almost half a ton without the contents.

Not particularly heavy, spread over solid bedded slabs. My shed (below) is clad in Cedral boards at 11.2 kg's per board. That's 470 kilos just for the Cedral boards. Then there's the windows, doors, timber, roof, internal ply boards, floor, fixings, gutter fascia etc.

shed.jpg

• noseall
• 4 Dec 2022

 

[freddiemercurystwin]

Got a link to the shed? I'm intrigued as to a heavy duty shed that only requires a 50mm base.

 

[perky416]

Motorbike Storage Garage 7ft 4" x 8ft 11" - Police Approved

The Gladiator

www.asgardsss.co.uk