Scrapping power floated floor and going conventional slab

[flanagaj]

Having been unable to find anyone who seems half interested in doing our specified power floated floors, we have decided to go with a conventional ground supported slab build up with the insulation on top of the reinforced concrete slab.  I decided to go with 150mm insulation on top of the slab simply because I didn't want to have the really long warm up times I'd get if I had a 150mm slab with a 70mm screed layer on top.

Can anyone explain or show a diagram which details how the screed layer, inner block leaf and PIR come together at the door reveals when you have a level threshold.  Does the PIR simply protrude into the reveal and mate up against the internal face of the outer brick leaf?

[Russell griffiths]

Change the pir out for xps insulation in the door area, look for one with a high compression something like xps 500. 
you have a cavity build up so will be a bit different to mine, but basically leave the inner blockwork low, fill your cavity with whatever you are doing and set the xps down solid onto this lower structure, doors sit on that, with whatever dpc you deam necessary 

don’t use 150 mm insulation, get 75mm and do two layers. Easier to cut and you can stagger the joints. 
 

 

[flanagaj]

13 minutes ago, Russell griffiths said:

Change the pir out for xps insulation in the door area, look for one with a high compression something like xps 500. 
you have a cavity build up so will be a bit different to mine, but basically leave the inner blockwork low, fill your cavity with whatever you are doing and set the xps down solid onto this lower structure, doors sit on that, with whatever dpc you deam necessary 

don’t use 150 mm insulation, get 75mm and do two layers. Easier to cut and you can stagger the joints. 

Ok, thanks.  I didn't consider using two layers of 75mm instead of a single 150mm layer.  I can see that by staggering the joints, you negate any potential cold spots where the insulation butts up together.

[Mike]

2 hours ago, flanagaj said:

I didn't consider using two layers of 75mm instead of a single 150mm layer.

2 layers is definitely a good idea.

 

If you have a nearby installer, sprayed high-density PU foam is another option that's very common here in France. For example https://www.youtube.com/watch?v=CSZ2Mhtbq_M

 

[Nickfromwales]

4 hours ago, flanagaj said:

Having been unable to find anyone who seems half interested in doing our specified power floated floors

You could just use self compacting / levelling concrete. Completely negates power floating altogether.

[saveasteading]

1 hour ago, Nickfromwales said:

Completely negates power floating altogether.

Is that assuming another finish will cover it? eg  carpet/ tiling?

I've never seen it but have seen the ripples in flowing screed.

 

I've looked up the blurb and it seems to mention mainly that it flows around reinforcement and complex shapes. Flooring is mentioned less, and one 

reference said suitable for domestic (implying only domestic?) and that it doesn't need a screed over it.

 

It's surprisingly difficult to find out more, especially technical stuff about strength and surface tolerances.

any references would be welcome as I dont like to not know this sort of thing.

@Nickfromwales presumably you've used it. Is it like  screed finish? What cost relative to old fashioned pump mix?