Incorporating a stairwell into concrete slab for an extension

[StuartC1969]

We are building an extension and as part of the plan is to build a short stairwell down into the garage so we can access it internally - the plan we have designed requires that the stairwell is incorporated into the concrete slab with 150mm hardcore; 50mm of sand blinding; DPM; 2 layers of wire mesh and then 150mm of RC35.

I get how this is applied to the stairwell floor and the slope on which the stairs will be fabricated on top as part of the finished floor layer.

the question is how to you do this on the verticle sides of the wall - I assume it's using some shuttering and then wakering that but can't visualise it at the moment.

Any ideas appreciated?

Stuart

 

[StuartC1969]

Looking at this in more detail I am assuming the DPM goes straight onto the earth i.e. there's not hardcore on the sides?

 

[KenGMac]

What I have seen happen on numerous occasions is that the "slab" is locally thickened and the hardcore is shaped which means the depth of the concrete is increased,

The shaping of the hardcore starts about 0.5.m from the proposed wall of the stair the DPM can still be laid on top of the over-site concrete or sand blinding [must admit My preference is for "Over-site Concrete" with the mesh kept in line with the rest of the floor.

 

[StuartC1969]

I get it - thank you for your response