Greenhouse Footings

[jake-the-peg]

I'm putting in some footings on soft relatively soft soil (previously a vegtable plot)for a greenhouse.

The shuttering is 30 cm or so wide and about the same deep dug into the ground with hardcore put in.

Should I be incorporating some rebars in this?

[The Builder]

Bar would certainly strengthen the concrete Jake. The trouble is, that doesn't address the problem. If there is any topsoil/organic material under the concrete, settlement is likely.
Bar simply mean the strip will be unbroken.

If you can't get down to subsoil or better, then a more effective way is to create a concrete "raft". That is, a square of 100mm concrete over 100mm hardcore) the size of the whole greenhouse.

It still breaks the rules over building off compressible material, but at least any settlement will be over the whole area. The whole thing may list to one side eventually, but at least the g/house will stay intact.

[jake-the-peg]

Yes, I was trying to avoid putting down a pad as we want to grow in the soil in the greenhouse.

But the greenhouse is aluminium frame so is relatively light and slightly flexible compared to say one with a dwarf wall so I can probably get away with a small amount of settlement.

I think I'll hammer down the hard core and use some rebars to try and prevent breakages and then take my chances. I'm going to have a wooden batton between the greenhouse and the concrete too so that'll probably help

Thanks for the advice

[The Builder]

Yes, that will help, Jake.
As always with these things, I'm going by the book. You'll most likely be fine.
Although the g/house is lightweight, there is the high self-weight of the concrete.......... so, make sure the bars cross each other at the corners.

That'll at least keep the strip working as one, rather than as 4 independent strips.