Concrete floor insulation

[emailrob]

I have a concrete floor in my garage / soon to be converted playroom.

The building regs guy says I have to put solid or some sort of insulation down. This is the foam/polystyrene boards, and then put chip board or plywood down.
Has anyone done this? Is is easy?

I've been given a price of c£35 a sheet (1200x2400) is this reasonable?

Any advice would be great

cheers

 

[Scoby_Beasley]

If you are talking about polystyrene as in ceiling tiles, as far as I am aware butting and taping together will give you a very firm base.
Been used for fish tank supprt for years and you cannot compress polystyrene, punch a hole yes, compress no. but you will need to some how fix the timber on top.
Price doesnt sound too bad but shop about, bargains are always there

 

[masona]

They are many ways of doing this and depending what height headroom you've got.You could use say 4"x1" timber on the flat side screw down to the concrete base and use T & G chipboard on top in the middle of the 4"x1" to support the joint and in between the frame work use 1" polythene foam.If you want thicker insulation,then use 4"x2" instead of 4"x1" timber and squash down rool wool insulation etc.

or

If you want you could use joist hanger on either side of the walls etc then wool insulation between joists but you will be coming up slightly higher.

All this depend what your building inspector will let you do.

 

[DAZB]

An easy job for a half decent DIY'er. What you need is 8ft X 4ft sheets of 1 or 2 inch ( your preference ) Jablite Insulation (it's just expanded polystyrene in slab form) laid to cover your concrete floor and then 8ft X 2ft sheets of 18mm Tongue & Groove Chipboard laid and glued along every tongue with standard PVA wood glue. Leave a gap all around of 10-12mm from the walls for movement.This forms what is known as a Floating Floor and your new skirting will cover the gap you leave around the edges.Have a look at this example using Polyfoam Floorboards.....
http://www.knaufinsulation.co.uk/application/applica.asp?AppID=48

 

[masona]

Jablite Insulation (it's just expanded polystyrene in slab form)

Never use this before,do you know if they're are rigid or springing type?

and will the chipboard eventfully touch the floor on heavy foot traffic?

Does the builder merchants stock them ?

TIA

 

[DAZB]

It will not compress under the Chipboard because all the Chipboard is glued together acting as one surface and evenly spreading the weight. I have done this umpteen times during cellar conversions and you would never know if you hadn't seen it done. It is just like walking on a normal floor and you also have the insulation factor. Any builders merchants should stock the Jablite slabs although they may come in a smaller size slab ( possibly 4ft X 2ft ). Another more expensive choice would be the Kingspan slabs but they do the same purpose.

 

[emailrob]

Thanks all, I'll just have to price it up. We need 60mm minimum, so I guess the 2" ones will have to be them.

Is it necessary to stick the actual boards to the floor, or can they just be 'placed' in?

cheers

 

[MrHelpfull]

I too have done exactly this, and found no need to fix the slabs down at all. Just be careful not to walk on the insulation, lay a spare board down to walk on, also when gluing the boards together ensure the tongue and groove is tight. The inspector I had insisted the insulation slabs were tapped together.

Got all of it from the local Travis Perkins, where a little haggling always drops the price, and delivered free.

 

[masona]

Is it necessary to stick the actual boards to the floor, or can they just be 'placed' in?

You can just rest the T & G chipboard on top of the foam providing you glue the T & G chipboards joints to stop them coming apart as Dazb's said it act as a floating floor.

 

[emailrob]

great, thanks all. Fingers crossed

 

[BiGDave]

This reply is a bit late sry! But have you a branch of http://www.encon.co.uk/ near you?
If so they have great prices on Kingspan/celotex 2440x1220x50 sheets
about £16-£18 + vat
Or ordinary flooring grade polystyene 8'x4'x2" for £4 ish + vat