Laying engineered Wood floor on fresh Concrete ?

aidancoughlan

Hi,
I'm getting a small extension built @ the back of the house. We plan to install a 20mm engineered oak floor, but the installer said we need to wait three months for the concrete in the new extension to dry or 'cure' first.
He offered an alternative : pouring the new floor @ a lower level than the rest of the house, and batten & fix a plywood subfloor first (up to the same floor level as the existing concrete floor) - then run the floor over the plywood. Apparent this will allow the concrete to have air circulate underneat, and the plywood protects the oak engineered floor from any moisture.

Does anybody have any experience of using this method to lay wood floors on freshly laid concrete, does it work OK in protecting against moisture? Will there be a different 'feel' on the wood floor laid over concrete in the house, and the floor in the extension over plywood ?

Could we fit half the floor, and do the extension later in 3 months, without separating them via a wooden strip ?

best regards & thanks,
Aidan.

nophd08

aidancoughlan wrote: »

Hi,
I'm getting a small extension built @ the back of the house. We plan to install a 20mm engineered oak floor, but the installer said we need to wait three months for the concrete in the new extension to dry or 'cure' first.
He offered an alternative : pouring the new floor @ a lower level than the rest of the house, and batten & fix a plywood subfloor first (up to the same floor level as the existing concrete floor) - then run the floor over the plywood. Apparent this will allow the concrete to have air circulate underneat, and the plywood protects the oak engineered floor from any moisture.

Does anybody have any experience of using this method to lay wood floors on freshly laid concrete, does it work OK in protecting against moisture? Will there be a different 'feel' on the wood floor laid over concrete in the house, and the floor in the extension over plywood ?

Could we fit half the floor, and do the extension later in 3 months, without separating them via a wooden strip ?

best regards & thanks,
Aidan.

I have both types of floor fitted, one directly glued to concrete and the other laid on plywood which is on battens. Both are ok. There is a different feel to the one laid directly on concrete,ie its very solid to walk on.
The way to go is leave concrete floor lower and lay ply on battens and then your wood floor, but I would have finished wood floor level with existing floor.
If you are having saddle board fitted between rooms then your wood will finish underneath it. It looks much better.
I would still leave concrete to dry out slowly and naturally over a couple of months.
Hope this helps.

Buford T Justice

It'll need to go off for a few months like the builder says before you can lay directly to it.

Carlow52

Stick with plan A
plan B is loads more work and expense and will need wall vents and cross ventilation and will negate any insulation in the floor in the extension.

buck65

Rule of thumb for concrete is a month for every inch to dry properly. Any bother with the floor afterwards you have no comeback unless the moisture content is below 4% or so.
Another option is to wait til the floor drops to 5% m.c and use a primer to seal the floor like Sika Primer MB. This gives a pvc style coating to the concrete.
Either way wait until the floor is dry. I think a subfloor with room to breathe isn't the solution either. Get the heat on and a dehumidifier and give it a chance to dry out.

aidancoughlan

OK, thanks folks for the replies.

I think we will avoid the "quick fix" options : will either wait & live with concrete floors all over for a few months (up to SWMBO), or put an oak T-section between the rooms and leave the new extension bare until it dries.

Unfortunately waiting for it to cure delays skirting boards, architraves, kitchen Island etc. for several months. Wish we thought of this first !

Thierry

Can I lay wooden floor directly over concrete? I am putting a self levelling compound to have it smooth and flat.
What type of glue, should I use?
Do I have to waterproof the render first?

slimjimmc

The same rules apply regarding moisture content of the concrete and the levelling* compound. The minimum acceptable moisture content is specified by the flooring manufacturer.
If laying solid boards the adhesive should act as a moisture barrier.
If you're laying semi-solid boards they shouldn't be glued, just put a sheet of PVC as a moisture barrier then a foam underlay then boards.


* it's not self-levelling, you need to trowel it out to an even finish, can't just pour it and expect it to self-level out to a flat surface.

cnocbui

The Latex based self-leveling compound does self-level if you are really quick at mixing, pouring and spreading.

creedp

If laying solid boards the adhesive should act as a moisture barrier.
If you're laying semi-solid boards they shouldn't be glued, just put a sheet of PVC as a moisture barrier then a foam underlay then boards.

Just for clarification, my understanding is that you can and should glue semi-solid/engineered wood to the screed if using UFH. Is this correct?

In relation to the glue being a moisture barrier, if it is so then why is it necessary to let screed dry out to 0% moisture content before laying wood?

Thanks