Solid Oak Floor on concrete

[Stan44]

Hello all,

I intend to lay a new solid oak floor (John Boddy Timber) onto concrete. The concrete has been laid above 8" of well compacted hardcore, 2" polystyrene insulation slab and a top quality DPM. The concrete was laid 12 months ago and is bone dry.

The concrete is flat and level but does have a few ripples from tamping and so I intend to fix 6 mm wbp ply to the concrete and then glue the oak to this. My question is: how well does the ply need to be fixed? Obviously screws and plugs but how many per sheet? This perhaps sounds silly but as I have 150 sq. m. plus, this is going to mean an awful lot of drilling and screwing!!

The floor is, by the way, nearly 10 m wide.

Thanks for any suggestions which will be much appreciated.

 

[WoodYouLike]

Nearly 10 meters wide means it is too wide to install Solid Oak floorboards safely. You'll have to change direction of the boards halfway and use a loose tongue to keep the two halves "connected", plus you need at least a 35mm wide expansion gap around the whole perimeter of the Oak floor.

If still possible, switch to wood-engineered boards!

 

[skotl]

Nearly 10 meters wide means it is too wide to install Solid Oak floorboards safely

Apologies for the dumb question (I was just lurking, and don't have 10m of room to floor) but why is this?
I'm going to guess that it's to do with expansion of the oak boards?

Cheers
Scott

 

[Stan44]

Yes, quite correct.

It seems that around 5 m is the safe maximum after which you need to install a loose tongue.

I am obviously going to have to look at engineered boards since a change of direction in the floor would look terrible.

 

[WoodYouLike]

Think you misunderstood the switching of direction here Stan44 - my mistake for not explaining properly.

You normally start the installation with the tongue of the boards towards the wall. In wide areas, such as yours, halfway you turn the direction around - meaning you have two grooves facing each other (hence the use of a loose tongue) and then you continue to install the boards with the groove facing the "starter wall.

But still think it is best to switch to wood-engineered boards.

Edit: hope this image explains it better

 

[Stan44]

Many thanks. Yes, I had misunderstood - old age etc.

I have had a good look at as many previous posts as I can and am fairly sure I understand all the relevant points. I will, however, e-mail you direct just to be sure.

Thank you again.