Concrete slab pouring

[Richskirich]

Hi!

I'm building a large shed/workshop (6x3.5m) at the top end of our garden. It might potentially have a car in it on occasion. I have read that 100mm should be deep enough. I have dug down to subsoil with a digger as it was on a slope.

My question is 2 fold. Firstly, should I be using rebar? If so is there a particular grade? Am I right in thinking I will need to cut joints into it as a single slab? Is halfway up (3m) enough?

Secondly, what timber should I use? I have found timber the correct depth but it isn't long enough. Is there a particular method of joining two lengths?

Thanks! Any advice welcome!

 

[Richskirich]

Sorry, just to clarify

I mean the timber for my form.

 

[kingandy2nd]

I wouldn’t cut a joint in it, but it won’t hurt if you do.

In the extension I’m building I put A193 mesh in the concrete for strength, although some will say it’s not needed.

You can simple connect lengths of timber together and put stakes in either side of the joint. You can put some additional timber behind the form for extra strength.

You’ve not mentioned your sub base. 150mm Mot 1 compacted would give you a solid base for your concrete.

 

[Richskirich]

Thanks Kingandy2nd!

Well I was just going to lay it on the soil. It is quite hard. But I think I will use Mot 1 now after reading a bit more. Better not to take the risk in the long run and I'm guessing it will help with drainage.

Thanks

 

[dontbelieveawordofit]

an extension isn’t the same as a shed. 6” of sub base and 4” reinforced concrete for a wooden (assuming it’s wood) shed is excessive and a waste of money imo.
dont forget your dpm.

 

[Notch7]

the answer to your question depends on ground stabiity.

is the ground load bearing and does it have shrinkable clay

do you have trees in the zone of influence -say within 10 metres or so.

leylandii hedges also an issue.

in general a load bearing slab is best done with well compacted type 1 and a bit of rebar

for shuttering use cheap 6 x 1 gravel boards, join on the outside with an offcut of the same
they will be a bit bendy but use pegs as needed and put some bricks behind to wedge to edge of untouched soil