Raising Concrete Floor Height Using OSB then Laminate

[Bokvis]

Hi, appreciate guidance please

The concrete floor on our new extension is 13mm lower than the main house floor or 23mm to the top of existing carpet in the house. We are looking to install laminate 8-12mm flooring on top of either OSB or plyboard providing the overall 23mm thickness

I have tried to investigate online by getting varying viewpoints from flooring companies and contractors i.e. do not use OSB or do not use ply .... or visa versa. Some people say you can as long as you glue or mechanically fix the boards. Also varying comments regarding using a self levelling compound - cannot be used as the layer required is too thick

Has anyone undertaken an installation using OSB or ply with laminate on top .....appreciate and comments or advice please with thanks

 

[charliegolf]

It's a cost thing, but what about 14mm engineered wood* on a 5mm underlay? By the time you have a doorbar/threshold in place, you'd be pushed to see the 4mm difference.

*nicer finish too

 

[oldbutnotdead]

13mm is fine for some SLCs- B & Q's own brand stuff does 3-30mm as far as I remember. Or 12.5mm Marmox insulation board would go well if the concrete is flat

 

[noseall]

Hi, appreciate guidance please

The concrete floor on our new extension is 13mm lower than the main house floor or 23mm to the top of existing carpet in the house. We are looking to install laminate 8-12mm flooring on top of either OSB or plyboard providing the overall 23mm thickness

I have tried to investigate online by getting varying viewpoints from flooring companies and contractors i.e. do not use OSB or do not use ply .... or visa versa. Some people say you can as long as you glue or mechanically fix the boards. Also varying comments regarding using a self levelling compound - cannot be used as the layer required is too thick

Has anyone undertaken an installation using OSB or ply with laminate on top .....appreciate and comments or advice please with thanks

I used ply - no problem, when going from a suspended timber floor over onto a lower concrete floor. Made sure that the ply bridged the cross-over point with a bonded joint.

 

[cdbe]

12mm laminate + 5mm underlay is close enough for the human brain to make up the difference.

 

[^woody^]

OSB or ply will be fine, with a token gesture of adhesive purely to stop them moving sideways or spreading apart, not for holding them down.

The main concern being concrete would be an uneven or unlevel surface. So self leveling first may be necessary or prudent.

You would not normally measure a new finished surface to the top of existing carpet though!

 

[Deluks]

That green fibrous underlay board is about 5-6mm and cheap as chips.
Double it up or use with some 9mm ply.

 

[Bokvis]

Many thanks for the advice. So to be clear if i consider using OSB or Ply on top of the concrete floor the build up would be
- concrete floor
- adhesive
- OSB or Ply
- underlay to deaden sound
- laminate floor

I have a dpm underneath the concrete slab, so assume no extra protection required. Apologies for requesting confirmation but dont want to make an expensive mistake. For info, the new concrete floor slab is 16mm lower than existing concrete floor (without the carpet + underlay)

Thank you all again for your help