Concrete shuttering

[Osprey]

Going to be casting a large concrete slab floor for a combined garage & car port.. structural calcs done, buildding regs approved ... aprox

6.6m x 8.5m 300mm depp x 450 wide thickened at edges and centre wall, rest is 150mm thick (with a lot of steel)

Anybody done any shuttering recently for something this size ...

Assume I use pylwood shuttering with a wood backing frame at top, bottom, edges and presumably at something like 600mm centres.

What thickness shuttering ply ? What size for the support framing .. 50 x50, 75x50?

Guessing that I will use some 45 degree struts to help brace this in place, and probably some steel pins (15mm diam x 900mm) ... driven in at corners and maybe at 2m intervals, to stop form work bowing when the pour is made.

Open to any advice if somebody has done this recently.

[mrcheerful]

Hire some steel formwork or the edges will wander around all over the place.

mrcheerful

[Osprey]

I did consider that .. but it is far too expensive.

[mrcheerful]

then just do the best you can, I regret the time I put down umpteen tons of concrete without steel formwork, however the wavy edge effect is hidden by a fence now. the cost of hiring some formwork is well worth it, I believe, for a proper job.

mrcheerful

[meow2222]

There may be an easy solution to that. I say may be cos I havent tried it. Put your woodwork in place, then pour concrete round the _outside_ of the wood. This will be a very small volume and weight of crete. Now pour the inside. If your wood is above ground, let the outside set first. If the wood is below ground, no need to wait, just pour with the same batch.

Anyone tried this?

NT