Floor slab

[akist]

We are converting garage to an annexe. We will put 100mm Celotex over existing concrete slab and then 65mm of concrete screed over that. However the existing concrete slab has an incline from the back to the front, I presume for rain water drainage. The incline is 2 bricks height (150mm) over 5.7 metres.

I have discussed it with builder and I suggested we pour concrete over the existing slab and thus level it. He disagrees (as usual) and wants to put some sand-mix down instead (he used a name but I forget now). He thinks concrete is not necessary and is more costly.

What should I do?

 

[^woody^]

Sack the builder

 

[Notch7]

We are converting garage to an annexe. We will put 100mm Celotex over existing concrete slab and then 65mm of concrete screed over that. However the existing concrete slab has an incline from the back to the front, I presume for rain water drainage. The incline is 2 bricks height (150mm) over 5.7 metres.

I have discussed it with builder and I suggested we pour concrete over the existing slab and thus level it. He disagrees (as usual) and wants to put some sand-mix down instead (he used a name but I forget now). He thinks concrete is not necessary and is more costly.

What should I do?

You should tell him hes got to cut tapered insulation

 

[^woody^]

In principle, having different insulation thickness increases condensation risk. Insulation should be kept as a layer of the same material and thickness.

Let alone the notion of having 250mm deep insulation at one end.

 

[akist]

I think he meant it sarcastically...

OK so it is between some sand-type mixture or poured concrete. Can you see a reason why I should not pour concrete over the inclined slab and thus level it?

Many thanks for advice BTW