Laying A New Floor In A Garage

[thechauffeur]

I am converting my sons double garage into a playroom/ store room. I have put up a ceiling and insulated it. I have insulated the walls with cellotex and plasterboard. Now its the turn of the floor. The floor is screeded concrete and I am in two minds wether to lay battens then 18mm t&g chipboard with polystyrene sheet between the battens, or to just lay some thin insulation and lay a floating floor, the kind that snaps together. I would be grateful for any advice or any other suggestions .

[The Builder]

Not polystyrene though ..... Celotex or Kingspan are twice as effective as polystyrene.

Either battens with Celotex between them, or a floating floor. The thickness will depend on how much you can afford to raise the floor level before you have "step into the house" problems.

Floating is very easy. Lay all the insulation across the whole floor...

Cover the whole lot with thin polythene sheet as a "vapour check"
This prevents moisture (in the vapour) from getting between the insulation sheets and condensing on the cold concrete. Alternative to polythene is to tape all the joints in the (foil-faced) insulation. It'll do the same job.

Simply cover in T&G chipboard. It's essential to pour some neat PVA into each groove before fitting the sheets together. This glues the whole lot together to create one big sheet, as it were.

Also essential ... leave a 10mm expansion gap around all four sides at the walls. This is usually covered by the skirting board. It lets the floor expand and contract as it likes, without you seeing it.

[thechauffeur]

Thanks for your advice. So if I laid Celotex and a vapour barrier which I have already used on the walls , are you saying I don't need battens? Would I have to screw the t and g sheets through and into the floor or will the glueing of them suffice in stopping any movement ?

[The Builder]

Definitely NO battens, Chauffeur. That's why it's called a "floating" floor.

Definitely NO fixings needed. It really does just "float".
For a short time, you'll experience some creaking and cracking as it beds in. Nothing to worry about though.

[thechauffeur]

Thank you so much for your advice