Greenhouse Footings

[ohdearme]

Hello All

I am digging a rectangular trench for a greenhouse I intend making.

I'm thinking of laying 3 to 4 inches of concrete in the trench. Do you think I should pour that onto a layer of agregate/hardcore or straight in please?

Then, a membrane then a timber frame, then paving slabs?

What do you think? Hoping to hear from some kindly person.

 

[Mr Chibs]

I’d hardcore first, then concrete.

I would also lay a course of blocks/bricks all around on top of footing.

If you just build off the Footing the wood (if that’s what your using) will be below/level with ground and wood will be wet and rot quickly.

 

[ohdearme]

Sounds good Mr Chibs. Something like aggregate perhaps? Do you think that 2 inches deep of that together with my say 3
inches wide of concrete in a 3 inch wide trench would be enough?
Many thanks.
Alan

 

[Mr Chibs]

Ideally you’d want the footing to be wider than brickwork. 75mm wide footing won’t really be wide enough. it may be difficult to line up with the bricks depending on how neat the trench is.

Really you could do with 200mm, so you’ve got some weight to the footing.

Why not a 300mm wide, 100mm deep, sat on compacted hardcore/aggregate.
You could then lay a block border, by laying the block on its back. Would give you a wide 215mm base, and around 110mm high... which will give you options when you build the framework.

What are you intending to build the frame out of... size wise?

 

[ohdearme]

I think that's exactly what I want. Hopefully going a bit bigger on the foundations and base than I intended won't cost too
much more.
The stud timbers they sell at B and Q and Wickes are 2.4 metres long, so that's convenient, x 6 feet (1.8m).
thereabouts and I will build the frame from those. Such a good idea to lay them on their side.
Thanks, hope you had a lovely weekend.
Alan

 

[Mr Chibs]

Forgot to say, you could leave a gap between some of the blocks for ventilation, presume your floor will be wood?

That way, whichever direction the wind is blowing it will circulate and blow away damp.

I’d lay a sheet of dpm on the ground as well, just weigh down with bricks.

good luck

 

[ohdearme]

I'm thinking of laying paving over a membrane.

A gap? Do you mean like in my little drawing (Attachment)?

Thanks for the "Good luck". I'm beginning to feel a little better.

Alan

 

[ohdearme]

All decided now, with your help everyone. Many thanks
Alan

 

[Mr Chibs]

Yes just like that, sorry late reply

 

[ohdearme]

Keep well, Bye