Hi All,
Does anyone know anything about floating floors?
I have a concrete foundation 6Mx3M and want to do a floating floor instead of joists etc.
200mm of styrofoam straight onto the concrete and then t&g chipboard straight onto the styrofoam.
No idea who to ask or where to start, but need to move fast as need to get Building control to approve it and it effects the builder starting on the bricks as there will be no holes required for the joists etc.
Pat...

what is it you want to know .done this a few different ways 2x1 battens with rubber 10mm cuchioning fastened to it .rockwool with 2x2 battens then styrofoam.all need visqueen underneath and 150mm up the walls

No real problem with what you want to do, have a look at the dow web site. Remember it doesn't need to be styrofoam, there are many rigid insulation board products available such as jablite, kingspan encon etc. The link is for the styrofoam site with a detail showing what you noted in your post. If you need more help u2u me I'm a Building Control Surveyor.
http://www.dow.com/styrofoam/europe/uk/ins/floors/gb/index.htm

Cheers delboy.

I couldn't find those pics before but pic#1 is exactly what I want to do.

Trouble is that it would need to be 450mm thick.

There are two airbricks on the house wall that would have to be vented through the styrofoam to the outside wall via piping of some sort (soil pipe?)

What would I need to submit to building control as my plans currently say joists etc?

Would the spec and pic from the DOW site be sufficient?

Main question is the depth though.

Thanks,

Pat...

My plans for new extension show

4" concrete on a vapour proof barrier,
4" of kingspan insulation.
2" of top screed. Underfloor heating pipes to be laid into the screed.

The whole lot will thenn get tiled and bocome a huge radiator.

Pat,
Coozers pretty much right with his figures for Kingspan, i calculate that using a poor perimeter over area value of 1, to acheive a satisfactory u value of say 0.22w/m2K you only need 75mm of Kingspan Kooltherm K3 in your proposed floor make up. I know that styrofoam isn't as good in terms of thermal resistance, however, you certainly won't need 450mm. I've attached the web address for the appropriate Kingspan site to confirm what I'm saying.
http://www.insulation.kingspan.com/uk/pdf/k3.pdf
As far as Building control goes, you really need to ask them what they will accept, some Local Authorities will accept a revised specification like the one shown in the brochure and some would want a revised plan with the changed specification noted on. It really depends on their interpretation of the regulations and how much they want to stick to the requirements of the act. I'd speak to them, most of the guys will do their best to help you as it makes their job easier. Hope this helps and good luck.

It'll definately meet the U value, it's just that to bring the floor level up to the same as the house so you don't have to step down into the extension, I need the floor level to be 450 above the concrete.

I think it would be easier and cheaper than joist, air gap and insulation.

Pat...

When I saw the title I thought you had maybe moved to South Yorkshire or Gloucestershire - plenty of people there with experience of floating floors this year.

Given the high cost of phenolic insulation boards like kingspan, and the extra concrete needed to form a floor slab, i think that joists with glass wool suspended between them would probably be cheaper. You would still need flooring either way so its concrete and high spec insulation against joists and glass wool. No need to change your approved plan either if you use the joists.

The only way to raise your floor by that much, is by either, timber joists, or block and beam, with the later you can use 2" polystyrene with a polythene barrier, then glued chipboard flooring ,wedged around to hold it tight while the glue goes off.

Yep - after looking at prices, looks like joist will be more cost effective, although not as easy and simple as foam boards.

Was just a thought!

Thanks all,

Pat...