Concrete pad advice for a small summerhouse

[Cellophaneskies]

Hi

We’ve ordered a summerhouse, about 2.2x2.2m square. It will need a concrete pad to sit on and wre considering doing this ourselves.

I’m seeing conflicting advice online and from tradesmen too. I read that it needs 100mm sub base (mot type 1, compacted) and then 100mm concrete pad, with membrane underneath, and ideally a concrete mesh suspended on the inside for strength.

I’ve been told that I don’t need the mesh - overthinking - and that for this type of low weight, structure, the sub base isn’t needed. Ie compact the ground with a whacker, concrete pad on top.

I’m not really sure what to believe. Sounds logical that something light doesn’t need a super foundation but then equally I don’t want to have to ever worry about it moving or cracking!

Plus, the membrane, is that simply an impermeable plastic sheet laid on the ground, concrete directly on top? Of course I’ve seen this on Google but want to clarify my understanding.

Does anyone have experience or advice surrounding this? Many thanks.

 

[Wayners]

Depends on the ground but slabs or concrete is good enough.

 

[Deluks]

If you can dig it out a little bit and scrape back to undisturbed well compacted soil, then just shutter and pour a 100mm slab.

 

[Deluks]

Membrane just stops the ground/hardcore from absorbing the moisture out of the concrete. A thick polythene dusy sheet would do it.
Ideally the summerhouse would have a little bit of space between it and the ground. Does it have a built in floor?

 

[Why Not Indeed]

Make the pad the same size as the summerhouse. If the pad is too big, rain will splash up and shorten the life of the lower timbers.

 

[Cellophaneskies]

Membrane just stops the ground/hardcore from absorbing the moisture out of the concrete. A thick polythene dusy sheet would do it.
Ideally the summerhouse would have a little bit of space between it and the ground. Does it have a built in floor?

Yes has a built in floor.

I think I’m going to go the route of compacting down maple type 1 and then sitting the footings on top, not bare wood to ground but on some plastic runners or something. A bit less permanent - a lot less permanent in fact - easier, cheaper..