150 precast flooring

[Moggaman]

I know that local suppliers of precast flooring 150mm say that the flooring can be laid on a 100mm block (inner leaf of external wall). That is for normal cavity widths.... if i extend my cavity to 200mm and use longer ties, will this ability to lay the 150mm slab on the 100mm leaf still stand.?

I will be running this by building engineer before I start but I am just planning ahead and want to get a feel for it

 

Thanks

 

[Mr Punter]

If the flooring spans between the inner leaves it does not matter how wide the cavity is.

 

What insulation are you looking at?  A few of us are currently looking at brick / cavity / block construction with a 150mm + cavity.  The best poly beads and mineral wool seem to come out the same at 0.032 W/m.K.  I will get prices soon.

[Moggaman]

8 minutes ago, Mr Punter said:

If the flooring spans between the inner leaves it does not matter how wide the cavity is.

 

What insulation are you looking at?  A few of us are currently looking at brick / cavity / block construction with a 150mm + cavity.  The best poly beads and mineral wool seem to come out the same at 0.032 W/m.K.  I will get prices soon.

What do u mean if it spans between the inner leaves? Floor area is 100m2 so imagine they will span to a central wall internally that will be a block on flat 225 wide ....

After much consideration i am looking at sand cement render to 100mm block ,200mm pumped bead cavity, 100mm standard block inner leave , sand cement render with skim coat .

worried that 1)PIR board would not be put in correctly and 2)don’t want insulated plasterboard on the inside .

Edited December 2, 2020 by Moggaman

[PeterW]

The beams sit on the inside walls is what @Mr Punter means. If there is a supporting wall elsewhere then that just takes part of the load. Any reason for block on flat ..? You could save a lot of money using 140mm blocks. 

[Mr Punter]

With poly bead I think it can be quite difficult to get the wall ties in, as they typically build up one side and the wall ties end up hanging in space or just shoved in later.  With mineral wool the ties are supported by it.

 

Any point in 75mm PIR and 125mm beads?