Insulation Boards - Can I use Same Flooring and Underlay Combination? Information, help, tips and advice on cavity walls, ceilings and lofts etc....

[cmoorebling]

Hi guys,

In 3 bedrooms upstairs, I have just laid laminate flooring on top of fibre board underlay and a vapour barrier.
I am now moving onto downstairs and am in the process of trying to get quotes for sub floor insulation. If this turns out not to be cost effective in terms of what it will save me (I'm not sure if I'm confident tackling it myself) or even if I do do it or get it done I'm considering laying insulation boards on top of the sub floor as an extra layer of insulation.
I'm just wondering that if I do this whether I can happily use the same flooring/ underlay combination on top? I've read that it's not a good idea to use 2 layers of fibre board as the sub floor will then be too wobbly/ springy.

These are the boards I'm considering:
http://www.wickes.co.uk/Celotex-25mm-Hi ... m/p/190545

And this underlay:
http://www.wickes.co.uk/Wickes-Fibreboa ... k/p/215589

Thanks,
Chris.

[welsh brickie]

the 25mm celotex board has too much play in it to be an effective underlay for the flooring. If you laid chipboard tongue and groove boards on top, then your flooring then that would be fine, but that would be 25mm plus 18mm floorboard and then lay 3mm polystyrene foam underlay then the finish floor board of 8mm I don't know if that would be too thick for you