Tamping a slab 4.7m wide. One section, or two?

I’m about to pour my 4.7m wide garage slab, within a blockwork retaining wall. Can I level/tamp it down in a single section with a piece of wood (4.8/5.2m), or will a slab that wide require me to put something middle and tamp it in two sections? By that I mean just tamp it in two sections and when done remove the middle ‘rail’ and fill it in, rather than leaving an expansion gap.

It has to be level, but not necessarily perfectly smooth as I’m happy to throw self-levelling compound over it. I wasn’t planning on power-floating it or anything like that as it’s just a garage floor.

Cheers for any replies!

Tamp it the full width. Bull floats will smooth it.

I don't think that you will have any success with such a long piece of wood. Doing it in two sections would make it more manageable. If you cast the cement with a "spine", then the spine wood will have to be broken out, unless you can reduce its thickness (for removal). One way would be to make it out of in two pieces of 2" X 1" with many (one every foot?) spacers nailed between the 2" faces, so when it stands up it looks like a ladder. Put it down so after the job you can run a jigsaw down the length to cut the "rungs", hopefully you can wriggle the two halves out. A method I have used is to key the two faces together by facing the spine wood with hardboard and poke 12" of 3/8 bar through so its under the main piece of wood, but is at least 2" of the hardcore and there is 12" sticking out into the air. So you pour the first side, let it go of, remove spine wood and hardboard, leaving you with bits of the rebar sticking out through the thickness of the base. Pour the second side using the first side as you shuttering. I have tried to cover the shuttering with plastic parcel tape, it wears through very quickly. Difficult to get a smooth surface with plastic bags, I suppose loads of drawing pins might help.
Frank

Your making a big job out of it ooh dark one.

Thanks for the replies. I'd rather keep this as simple as possible. It's a 4.7 by 5.7 meter slab so it's not a massive area overall. I'll have nothing else to do that day, so I'll be able to spend a while levelling it. I think I'll just do it as one.

I've got a volumetric mixer coming, so I guess I can get him to make the mix slightly wetter, which I reckon might help?

theprinceofdarkness> Your method sounds interesting, but I'm laying a DPM underneath so I don't want pierce that with anything like rebar.

Cheers for the replies.