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Garages & Sheds

How should an area be prepared for concrete pouring?

I have been clearing an area which is going to have a large concrete base for a shed and greenhouse to be sited on and have a walkway in between them.
The total area is about 250 SqFt (11' x 23').
The area has fence panels around it with concrete posts and those small concrete panels below the wooden panel.
I have cleared the aread and dug down -I just need to know how deep the concrete needs to be and if I will need harcore or is it ok to pour the concrete onto compacted soil?

I will probably get someone in to do the concreting but I'm trying to save money by doing as much as the preparation as possible.

Thanks in advance for any advice

Thanks for the quick responses B J D BUILDING/ROOFING & tm property services

Just out of interest what would I have to pay for someone to complete this for me - It's all dug out - just would need the hardcore & Cement pouring

2 Answers from MyBuilder tradespeople

Best Answer

you need to dig out to a depth of 250-300 mm ,then fill with hardcore ( mot or crusher run) to leave100mm for the concrete,make sure that this is well compacted and level, you will then have to fix shuttering to the size of the base making sure it is level and square,allthough not essential for a shed it is advisable to put a waterproof memnrane down to stop damp rising into the concrete,hope this helps,regards, Terry.


Answered 2nd May 2011

For a slab that size, I would allow for 100/150mm concrete over 150mm well compacted hardcore, type 1 mot.
For extra strength add a couple of A4 steel mesh.
This is probably overkill for your job, but thats how I would do it, you could drop down to 100mm of type1 and same for concrete.
Dont lay the concrete directly over the soil, if the weather is warm, sprinkle with water when hardening of and if possible drape over some wet hessian.
If its only bases for a shed and greenhouse, it might be cheaper to put in 100mm type1, compact and lay some 600x600x50mm slabs on a sand/cement mortar.

In response to your following question, there is quite a bit of difference in prices, from tradesmen on here, as you may of noticed on previous posts.
But as a rough guide, if you had a tradesmen plus labourer, I would estimate they could do it in 2 days, say half day to do the hardcore and practicaly a day concreting, if you worked on about £150/£180 a day for the tradesmen and £80/£100 for the labourer, you wont be far of.
Obviously if its a cash in hand job, then it would be cheaper.
But I didnt tell you that.


Answered 4th May 2011

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