Concrete floor sub base

[MAXWELL]

What is the minimum thickness / amount of hardcore you should have as sub base for a concrete floor

[Russell griffiths]

Depends what it’s holding up. 

Ive laid concrete straight onto a plastic dpm straight on the dirt. 

But I wouldn’t put a house on it. 

[MAXWELL]

Its for the floor on an extension

[Russell griffiths]

Shouldn’t be any hardcore nowadays. 

Type 1 compacted

sand blinding

dpm. 

Concrete

insulation

screed. 

 

Or alternatively. 

Type1

thin insulation 

dpm

more insulation

concrete. 

 

Theres many ways to do it but hardcore and concrete should be left for a shed base, there is no way to compact it sufficiently to avoid voids in it. 

[Miek]

3 hours ago, MAXWELL said:

What is the minimum thickness / amount of hardcore you should have as sub base for a concrete floor

Domestic floor?

 

My spec was 150mm compacted sub base with a 100mm concrete floor covering. Insulation and screed on top of that.

[Conor]

We've just done 200mm compacted type 3 under the main slab and 100mm under the load bearing walls (to bear 200mm and 300mm of concrete slab). There will be a blinging layer of sand to protect the tanking membrane.

 

Building control guy was surprised we had stone down and was wondering why were weren't going directly on to the clay!