Reinforcing a Concrete slab

[STEVEROG]

I am planning to build a new shed/workshop in my garden. A friend has advised that it might be worth putting reiforcing metal rods into the concrete base beacuse I will be putting a very heavy lathe and other heavy kit on the floor. The existing shed base has a big crack down the middle, I definately want to avoid that!

The plan was to pour 150mm slab but I have no idea about reinforcing bars, any advice would be much appreciated (what size bars, how many, how far apart to space them, where to buy them etc).

Steve

 

[^woody^]

If you wanted to reinforce, you would not use bars, but a sheet of mesh.

Something like A98 grade would do.

And pack it up on 25mm high packers

And you should only need 100mm of concrete but make sure the hardcore base is well compacted on firm ground - minimum 150mm h/c

 

[Deluks]

A142 would probably be easier to source, most builders merchants keep it in stock.

 

[STEVEROG]

Thanks for the input, that sounds pretty straightforward. That all said I am now thinking of building a proper building instead of a shed.

Just out of curiosity, could I use a 150mm depth strip, say 450mm wide with rebar in it as the foundations for the walls of my new outbuilding or would I need to big the normal painfully deep foundations? Walls would be blocks, probably go the whole hog and have a cavity wall. If this is possible it would seem to be preferred over a lot more digging/getting rid of the earth/much more concrete etc.

Any thoughts?

That said, I guess with the real building (not a shed) the building control man will probably be the one to decide what is and isnt acceptable as a foundation so even if the thin strip and rebar was ok I might have to do the usual boat load of digging anyway!

Steve

 

[theoldun]

Agree with Duke, would use A142 as this is always available from stock. Most stockholders do not stock A98 due to its light weight and wire size.
Note. You should always have 50mm cover to mesh and RE bar not 25mm
Regards your second post, you could go for a raft, but by the time you have paid for a SE to design and do calculations for possibly six pads, a high tensile steel cage for ring beam, shuttering all round, then cost wise, without doing some figures would say that it would not be a lot different to standard foundation.
Hope this helps.
Regards oldun

 

[r896neo]

You will also find the wall to raft junction very difficult to deal with in terms of keeping water out. Strip is much better.

 

[STEVEROG]

Thanks to all for input

 

[handyman77]

100mm type 1
150mm concrete with two layers of a142 mesh!
Safe as houses!