Raising a floor - kingspan correct order etc

[sotal]

I asked a question on here a few weeks back regarding whether or not a utility room and toilet in the back of the garage should have a raised floor compared to the garage itself. (it isn't raised now)

The answer wasn't definite but I've decided to replace the wall completley and to try and bring it up to standard whist I'm at it - so will rebuild with 30 minute plaster board etc.

This has led me to decide to raise the floor anyway whether it's needed or not. I now need to know what is the best way to do it.

I currently have a concrete floor for the whole garage which includes the toilet and utility room all at one height. Do I just put kingspan down on this then screed on top, does it need any membrane? What is the best way to stop the screed flowing off the kingspan on to the garage floor? Do you just use wood to stop it?

Thanks


Also what thickness of insulation should I use, and what thickness of screed? I think I needed about 4" of step so approx 100mm. Is this stuff the right sort of stuff:

http://www.diy.com/diy/jsp/bq/nav.j...ndid=9273752&ecamp=trf-005&CAWELAID=266891220

 

[HuwRoberts]

Personally I would use the Celotex TB range, the thickness isnt really an issue as you are improving a situation so you are not bound to and certain 'U' values etc, plus timber is standard when shuttering for the screed.

If your not sure about the construction of the existing slab then for the minimal cost I would install a DPM to the underside of the insulation, Visqueen 1200 gauge. Better safe than sorry.