6m x 4m shed slab, how much

[gareth h]

Any advice please, I’m looking to put a lean to / carport next to the garage, local builder suggests 100mm thick, any idea on approx costs?
Thanks
G

[Drumroll]

gareth h said:

Any advice please, I m looking to put a lean to / carport next to the garage, local builder suggests 100mm thick, any idea on approx costs?
Thanks
G

With the weight of modern cars I would look at going 150mm thick. I would make sure there is reinforcement steel is used and the concrete is laid on Visqueen. But all that is irrelevant if the ground isn't well compacted and level before you place the concrete.

I would look to use a PAV1 concrete as it has frost resistant properties. I have been out of the industry (I was a Technical Manager for a Concrete company)
for a few years now, so can't really give you an idea of price.

[Lefty]

I wouldn’t worry about steel mesh, you can get readymix c35 with fibre threads in for reinforcement. Last time I bought some it was £130/m3 but I was getting 18m3, might be a bit more for the 3.6m3 you need (if you’re going 150mm).

You don’t say what the ground is like, you might want some hardcore and sand. It’ll need compacted, you can hire a wacker plate for that, maybe £20 a day.

A roll of DPM will cost you maybe £80 and you’ll need some timber to use for formwork (the edges of the rectangle you are going to fill with concrete). Hire a screed demon and a power float, maybe £60 for a day and you re all done.

Have fun!

Edited: my shed build thread shows the slab going in

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Edited by Lefty on Tuesday 13th January 18:02

[LooneyTunes]

Lefty said:

I wouldn t worry about steel mesh, you can get readymix c35 with fibre threads in for reinforcement. Last time I bought some it was £130/m3 but I was getting 18m3, might be a bit more for the 3.6m3 you need (if you re going 150mm).

You don t say what the ground is like, you might want some hardcore and sand. It ll need compacted, you can hire a wacker plate for that, maybe £20 a day.

A roll of DPM will cost you maybe £80 and you ll need some timber to use for formwork (the edges of the rectangle you are going to fill with concrete). Hire a screed demon and a power float, maybe £60 for a day and you re all done.

Have fun!

Edited: my shed build thread shows the slab going in

https://www.pistonheads.com/gassing/topic.asp?h=0&...

£130/m3 is cheap! Depending on where he is, he might double that for a small load. If looking for small quantities, the OP should be looking for “volumetric” deliveries. The trucks mix, dispense, and bill for exactly what is needed.

Fibres can be a good shout but there are two types: structural and non-structural, the latter being used to help prevent cracking (which they do really well). It seems harder to find concrete firms offering structural fibres.

If using reinforcement, it needs to be spaced away from the base of the slab. You can buy little posts to hold it but simpler is to buy some perforated engineering bricks, halve them, and stand the mesh on those.