Prep For Laminate

[securespark]

Hi folks, long time no visit...

I have a suspended timber floor to prep for laminate. The floor is a mixture of imperial T&G boards and metric T&G boards, chip sheets and ply. Some of the flooring is 20mm, some 18.

So, I have discrepancies of around 2mm, maybe 3.

I have searched here and found a variety of advice, suggesting using anything from 3mm hardboard to 6 or 9mm ply in order to make a more even surface.

Some suggest wetting the boards and laying them damp, some just suggest conditioning them in the room for a few days.

On top of this levelling board, I intend to fit 5mm fibreboard underlay before the laminate, which is 8mm thick.

Personally, I think 3mm board is too thin, but 9mm too thick.

What do you suggest?

Cheers.

 

[IWalkLikeHimaMartian]

Bllomin' eck, SS I would have thought you would know to post this in the flooring section.

 

[securespark]

Thought I did.....
Hence the "long time no see" greeting.
Must be losing my marbles.

 

[IWalkLikeHimaMartian]

Thought I did.....
Hence the "long time no see" greeting.
Must be losing my marbles.

I sometime use the present tense when I really meant the past tense.

 

[Gerrydelasel]

Put 3mm acoustic foam on the sub floor, cover with 4mm ply, laid while damp, fix every 6 to 8 inches. Use a foam underlay on top like sonic gold rather than fibreboard, since it squashes and evens out more. Basically you'll end up with a layer cake of three flexible layers that progressively even out the subfloor defects. Hopefully this way you will end up with no hollows or 'bounce' in the laminate.

 

[securespark]

OK, thanks.

So,

3mm acoustic foam direct onto bare boards

4mm damp ply nailed through (presumably with 25mm annular nails (7+minimum board thickness (18) )

5mm (?) Sonic Gold

8mm laminate

20mm thickness of flooring.

 

[securespark]

If I use marine ply, should I wet it and if so, do I spray both sides?

And I guess both the sonic and acoustic foams are chiefly for sound. What if you wanted some thermal insulation?

 

[Gerrydelasel]

If I use marine ply, should I wet it and if so, do I spray both sides?

You don't need special ply, regular ply will do. Just dampen the top.

And I guess both the sonic and acoustic foams are chiefly for sound. What if you wanted some thermal insulation?

No, as I said you use them because they're squishy so they helpt to smooth out the lumpy subfloor, like the princess and the pea. The acoustic properties are just a bonus. They are very thermally insulative too.

3mm acoustic foam direct onto bare boards
4mm damp ply nailed through (presumably with 25mm annular nails (7+minimum board thickness (18) )
5mm (?) Sonic Gold
8mm laminate

Yes. Actually I meant to say 2mm foam and 6mm ply, but you get the idea. Yes ring shank /annular nails, or screws.

 

[TicTac]

Now I know that you're supposed to dampen hardboard, but I've never come across it being done on ply. Having said that, I've never dampened the hardboard, but I've seen it rise when someones spilled water on the floor, but it then shrink back, so I wonder if wetting it stops that happening.

Yes. Actually I meant to say 2mm foam and 6mm ply, but you get the idea. Yes ring shank /annular nails

Good suggestion, but screws will cut through the ply, so stick with nails.

 

[securespark]

Thanks guys. One last question: do I fix the ply sheets while damp?

 

[IWalkLikeHimaMartian]

No, you might catch cold. Dry yourself off first.

 

[securespark]

Yuk yuk!

 

[Gerrydelasel]

do I fix the ply sheets while damp?

Yes, otherwise there would be no point!

 

[securespark]

Doh, that's what I thought.

 

[securespark]

I lied about having one last question...

With my room being 2.6m wide, laying ply in 8 x 4 sheets would be doable, if a little cumbersome.

This way would reduce the number of joints.

Or would you use 4 x 2 and have more joints but an easier time laying (fnarr, fnarr!)??