Solid Oak TnG floor boards installation.. ??

[rekab6969]

Hi All,

Looking to install 22mm x 270mm solid oak kiln dried floor boards, in an Edwardian property.

So suspended timber joists with a dry over-site below, good air flow.

We plan to take up the existing pine floor boards to replace with the Oak.

The floorboard suppliers suggest a 1000 gauge plastic membrane laid over the joists, lapped up behind the skirting boards and screwed secretly through the tongue.

One installer suggests 18mm TnG ply laid down first then the boards fixed as above.

Another suggests that P5 TnG chip boarding would be ok again then screwed down through the tongue.

I have also seen the stick down rolls which would also act as a membrane..?

I realise that expansion is not to be under estimated, along with the moisture levels..

What moisture levels would be acceptable below the floor area?

All advice greatly appreciated..

 

[Notch7]

Generally solid flooring is best done with each board individually fixed in place -secret nailing -but if you do that, each board will need to expand and contract within its own space, so my guess is you will need an expansion gap.

I wouldnt recommebd floating floor method for solid oak and wide boards

The room should stay in the humidity range of 40% to 60%

 

[foxhole]

If you use a plastic membrane its going to stop all air flow and any spills will be captured and be absobed 100% by the timber, so would not suggest that.
Chipboard is poor at holding screws and worse with nails, so ply would be a better background for fixing to.I have used self adhesive underlay with oak and worked ok but if you ever needed to lift a board the lot would have to come up and cupping may be an issue with wide boards.
On balance I would say notch7 suggestion would be best, ply under if the current floor is uneven and the levels allow.
The last office I worked in used a clip system for floating oak floor, but was destroyed by one dishwasher flood.
Link for other ideas.
https://www.junckershardwood.com/wood-flooring/guidance/installation-methods

 

[rekab6969]

Thanks for your replies guys..

Notch. is the ply required if the joists are level, and each board can be levelled as it's laid.

Regards expansion gap I would allow one all around the floor on all sides, as it's TnG I would like to hope it would expand as one.. ??

Is a membrane required.. ?



foxhole.. I suspect the clip system was the thinner engineered type..?

The screws would hopefully pass right through the chipboard and into the joist below..

Regards floods it is to be installed in sitting rooms , entrance hall, and dinning room so a glass or two of wine or beer at the most..

Thanks..again..

 

[foxhole]

No clip system was used on Junkers solid oak boards. Screws would hold in joists but if you miss you wont know till its too late and only allow boards in one direction..

 

[rekab6969]

The last office I worked in used a clip system for floating oak floor, but was destroyed by one dishwasher flood.

Sorry, miss understood your earlier reply.. didn't view the link..

D'oh!

 

[rekab6969]

If the joists are level / sound and the correct distance to take 22mm boards is any boarding required..?

 

[conny]

TnG boards expand individually, not as one solid structure. Look at a shed or a door made from them. If the structure, (shed/door), is constructed and then painted/stained you will see the bare tongues when they shrink. I imagine a floor would be the same but on a bigger area.

 

[rekab6969]

Thank you for all your replies,

If it is screwed through the tongue direct into each of the joists, with a 1000 gauge membrane in place to deal with the humidity difference above and below, leaped up behind the skirting with an expansion gap all of it perimeter under the skirting board an acceptable way to install solid oak T&G..?

I appreciate there would be some movement of each board, thanks Conny, we just don't want it to start rotting from underneath, out of sight which I feel the ply would start to do.

Cheers,

db

 

[foxhole]

There should be no significant moisture to cause any rot even with no membrane below .

 

[Why Not Indeed]

If you need a membrane to protect the floorboards from moisture from below, what are you going to do to protect the joists?