Pour concrete for part of ground floor

[elite]

On my renovation most of the ground floor is concrete, however there is a 3m x 3m area which was quarry tiles straight on to earth, which now the stairs are out I need to fill.

 

What should I be aiming for, current thoughts are:

 

Dig down 250mm

100mm subbase - MOT type 1??

50mm sand

DPM

100mm concrete

 

I intend to mix on site with a mixer

 

The entire floor will have self leveller applied after the new concrete has cured

 

Questions:

 

Does this sound sensible?

 

Do I need rebar?

 

I have ommitted insulation as the rest of the floor doesn't have any - is this a mistake?

 

I'm not sure how to lap the DPM as the existing slab (I assume) does not have one - should I just lap it up the sides?

 

Thank you for any tips and advice

 

 

 

[Iceverge]

19 minutes ago, elite said:

intend to mix on site with a mixer

 

It can be done, it's only about 6 mixers. However..... I'd probably go for a volumetric mix or 1m³ delivered. It won't cost much more and it'll be a far more consistent pour. Concrete is heavy enough work without shovelling 2.5t of ballet and cement into a mixer on top of barrowing it in and shovelling it out too. 

 

23 minutes ago, elite said:

The entire floor will have self leveller applied after the new concrete has cured

 

No need if you're tidy with a hand float after the pour. 

 

24 minutes ago, elite said:

I need rebar?

 

No

 

24 minutes ago, elite said:

have ommitted insulation as the rest of the floor doesn't have any - is this a mistake?

 

 

Yes. 

 

24 minutes ago, elite said:

I'm not sure how to lap the DPM as the existing slab (I assume) does not have one - should I just lap it up the sides?

 

Yes.

 

 

I would put. 

 

Hardcore. A minimal amount really say 50mm  just to level the existing ground. The subsoil will be plenty stable under an existing house. 

 

EPS insulation direct onto the ground.( If nothing else it's far easier to cart in than hardcore) Say 100mm. 

 

DPM, lap it well up the walls and tack it there. It can be cut back later. 

 

100mm of concrete. You could probably reduce this to 75mm with some fibers in the mix to reduce digging and mixing. 

 

 

 

 

[elite]

Thanks - much appreciated