Large slab of concrete

[2019]

If one is pouring a 7.5 x 11m garage floor in concrete 6inch thick with steel mesh, which is best so I can get a level floor. There will be block on 4 sides.

Will it have to be split in 4 sections with timber with the one pour, tamp off the timbers then when setting, remove timbers then fill voids with concrete.

If so, how can one keep the timber in place without damaging the radon barrier or roll of dpc plastic or stop the timber from moving.

I have conrete pour experience however none this large in 20 years.

 

[Bonni]

My only knowledge is, don't go greater than 8m without an expansion gap. But when we did a 3m x 11m, we were told that steel mesh and one pour should be ok.

Concrete should be ST4 mix and any mesh/rebar should be overlapped 40 times it's thickness. So if the mess was say, 5mm, then you would overlap 40 x 5mm = 200mm. Don't forget to wire them together so they remain in place when pouring.

The concrete had freeflow added, waved it out with a length of gutter on a piece of timber and floated it off when we could stand on it.

 

[2019]

My only knowledge is, don't go greater than 8m without an expansion gap. But when we did a 3m x 11m, we were told that steel mesh and one pour should be ok.

Concrete should be ST4 mix and any mesh/rebar should be overlapped 40 times it's thickness. So if the mess was say, 5mm, then you would overlap 40 x 5mm = 200mm. Don't forget to wire them together so they remain in place when pouring.

The concrete had freeflow added, waved it out with a length of gutter on a piece of timber and floated it off when we could stand on it.

One issue that I have is how to install temporary screed timbers for tamping on for large areas without breaking through the radon barrier. If one has 150mm of concrete, the hychairs are raising the mesh up 75mm, then how does one set these screed timbers rails for tamping on without them moving.

On smaller areas where one can get to both sides with 5m lengths of timber is ok however on large areas, I'm finding it difficult to install them

 

[Paulg31]

Put some protection board down on top of the membrane, then something like some concrete blocks or sandbags behind it to stop it moving as the wet concrete exerts a lateral force.