Solid wood floor over concrete advice

julionumero1

Hi
Any advice welcome.
Looking to lay a solid wood floor over a concrete base.

Damp proof course is in place under the concrete slab although there is no insulation. Some sites recommend gluing the boards directly onto the slab however I was hoping to put some underlay & maybe thermafoil between the concrete slab & the boards.

Was really hoping to use this as an opp to get some insulation down (albeit with 3/4mm underlay) so method I was thinking was concrete slab, lay a roll of underlay, then battens, then thermafoil and finally secret nail the boards to the battens. Seems a bit much and would have a 20mm step into other rooms which I'm not keen on.

Aware of need to let wood acclimatise and for sufficient gaps etc.

Any advice or alternate suggestions welcome.
Thanks

North West

Hi
How long is the concrete down ?
what thickness do you have up to other floor ?
Is concrete level ?

Before you start there are a few things you need to know -
1. Moisture Content of concrete sub floor.
2. Relative Humidity reading of air in room.
3. All plastering/wet trades finished and dry.
4.The above factors will determine what type floor you can install.

Rent a moisture meter and humidity reader. take readings and send them to me and I will do the maths. Write down date you take reading because this part you have to get right before ever buying floor. A shortcut now will ruin your floor installation.

NW

julionumero1

Concrete was laid in August, perfectly level and dried out with heating & dehumidifier over six weeks.

All plastering and trades are done leaving me to do the skirting & architrave once the floor is down.

mp22

Some solid floor timber can be layed as if it was semi solid,if yours is engineered solid flooring ie,lots of bits glued together and machined to size.
Work away as if it is semi solid.

wildefalcon

The "floating floor" approach is probably the best - secret nail into battens cut from 18mm ply over the 3mm foam, over a layer of visqueen, if there is doubt over the DPC.

Leave the material season in the room for 6 weeks, leave a gap along the width of the material - no need on the length.

If the room is going to be anything other than completely bone dry then leave gaps every 3rd or 4th board - use a series of washers between the boards when nailing.

Door saddles can be removed and the floor material used to ramp up from surrounding rooms.

The gap between the battens and the floor could be used for insulation, I suppose. Shame there's no insulation under the slab.

julionumero1

Thanks Wildefalcon although using this method would leave me with a 2" step going into other rooms...

Question. Is it possible to lay it over the visqueen & 3mm underlay by gluing the T&G only i.e. not gluing the bottom of the boards to the slab??? This way I would still have (minimal) underlay/insulation but would have a smaller (by half) step into the other rooms.

Thanks all for replies

wildefalcon

julionumero1 wrote: »

Thanks Wildefalcon although using this method would leave me with a 2" step going into other rooms...

Question. Is it possible to lay it over the visqueen & 3mm underlay by gluing the T&G only i.e. not gluing the bottom of the boards to the slab??? This way I would still have (minimal) underlay/insulation but would have a smaller (by half) step into the other rooms.

Thanks all for replies

Yes, it's similar to the Junkers system, which clips each plank together. The floor will feel "harder" underfoot. Go easy with the glue - use evostick as it has a longer "open" time than the quicker and better trade stuff. Only use a thin bead.