Which chipboard + underlay +laminate combination is best?

[RakS]

Hi all,

I'm having a builder lay down some laminate for me and I wanted some advice interns of underlay and if additional sheets of chipboard would be necessary.

All the old carpet and underlay has been removed with just the original thin-ish floorboards left. The floorboards, while in decent condition aren't very pretty (it's a 1960s/70s built house) and there are a few loose/wonky ones.

Anyway, I was thinking of laying down chipboard to level out the floor, to guarantee stability, then lay this type of fibre underlay on top:
http://www.screwfix.com/p/wood-fibre-underlay-boards-7m/7824r#product_additional_details_container

On top of that I intend to lay my 12mm laminate flooring. Is this overkill?
The floorboards aren't too bad, and I figure hammering them down should keep and un-evenness/movement to an absolute minimum.

Which of theses options does in make most sense to go with :
1) 18mm chipboard + simple foam underlay +12mm laminate
2) 5.5mm fibreboard underlay + 12mm laminate
3) 18mm chipboard + 5.5mm fibreboard + 12mm laminate

The ares to be boarded are all bedrooms.

Thanks in advance for your help.

 

[Doggit]

Try 6 or 9mm ply screwed down with 20mm screws, then fibreboard, followed by the laminate. Make sure there are no services under the loose floorboards before you stick a nail (or screw) in.

 

[RakS]

Try 6 or 9mm ply screwed down with 20mm screws, then fibreboard, followed by the laminate. Make sure there are no services under the loose floorboards before you stick a nail (or screw) in.

Thanks for the advice. I was going to lay chipboard instead of ply for cost reasons. Why do you recommend 6-9mm ply? Would an equivalent thickness of chipboard be enough?

 

[Doggit]

It depends on what you're after. Ply is used to level an uneven floor, or at least provide a better flat surface for the laminate, so don't require more than a thin layer. If the floorboards are secured down, then I suspect they shouldn't require reinforcing with chipboard. You'll need to take about 25mm off of the bottom of the doors with the ply, but 35+ is you use chipboard, and that's not unmanageable, but it still a lot.

 

[dazlight]

Putting 18mm chipboard down won't level the floor? It will make it flat but will be same level.
I'd go 6mm plywood then use fibre levelling compound to get levels.

 

[RakS]

Thanks very much. I'll go for that option.
Does anyone have any opinions on this Vitrex Underlay instead of the fibreboard:
http://www.screwfix.com/p/vitrex-premier-wood-laminate-underlay-boards-5mm-9-76m/68038

The review seem good and, whilst upstairs in the house, the subfloor is old floor boards, downstairs it's concrete.
Thanks so much for all your responses