9mm ply subfloor on joists

[ACWbuckhurst]

Hi - my floor fitter has suggested nailing a 20mm engineered wood floor to the existing joists, with a 9mm ply subfloor in between to make sure a level surface. Joists are c 35 cm apart. Are there any issues with this approach I should be aware of?

Any thoughts gratefully received.

 

[JohnD]

How long are the engineered boards?

Has he ever done a floor like that before, and will he let you speak to the householder and stand on the floor?

Have you looked at the manufacturer's fitting instructions?

 

[ACWbuckhurst]

I am the householder!

Boards vary between 90cm and 230cm....it's a reclaimed floor.

I spoke to the manufacturer (Havwoods) and they said nailing directly to joists was OK. My specific concern is whether the subfloor is too thin, and might end up being too bouncy/squeaky....although open to any other potential issues.

 

[chappers]

If the manufacturers say you can nail direct to joists then the 9mm is unnecessary, you main issue is going to be hitting your joints onto joists.

 

[ACWbuckhurst]

If the manufacturers say you can nail direct to joists then the 9mm is unnecessary, you main issue is going to be hitting your joints onto joists.

Thanks Chappers, could you explain a bit more? Apologies, for the rookie question

 

[chappers]

No Problem. Your joints where the end of your boards meet should join over a joist, which will be nigh on impossible with random lengths and existing joists. You will have to fit noggins between the joists where the joints don't land on joists.