Flooring Question

Can osb be classed as plywood?

Hi, I just have a quick question, something that will quickly resolve a dispute. My builder stated to me that he would lay ply wood down as a Sub floor for wood flooring to go on top of and in the end he laid OSB, which he said was a kind of ply wood. Is it classed as ply?

5 Answers

Best Answer

It is not classed as ply but can be used for exterior /interior purposes the same as 18mm ply. We use this under flat roofs, forming dormers ect,1 to the builder, let him get on with his job.

Answered 25th May 2012


Member since 7 Jun 2008

You've been done.osb is half the price but will do the job.

Answered 25th May 2012

S M Joinery

Member since 16 Nov 2009

If you know what OSB means you will understand that it is the right choice. Eco building and wooden frame house are made out of it. Why?? Because well used it will bring all the frame perfectly square, it is light and stronger than plywood.
For a sub floor it has to be a minimum of 18mm thick if the joist are 40 cm from each other,if the joists are more than 40 cm from each other you must use a thicker osb. Also for more strengh and stability the OSB must be laid down following the diagonal.

Answered 27th May 2012

Luigi Guitart Carpentry

Member since 27 Apr 2012

Cheap option :)

Answered 25th May 2012

Roc builders

Member since 25 Aug 2011

If he specified that plywood would be used then he's reneging on his spec and the only reason he'd be doing that is cost.

18mm OSB/2 at max 600mm joist centres is permissible for suspended floor applications in dry conditions and OSB/3 in humid conditions for domestic applications.

I wouldn't use it though as I'm old fashioned and do not subscribe to the "OSB is the new plywood" school of thought.

Answered 25th May 2012

Amwell Property Services

Member since 11 Sep 2010

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