solid oak flooring

[BOBSSHOES]

could anyone tell me why my newly laid 20 mm solid oak floor is warping on each plank it has been laid by a proffesional carpenter directly onto a concrete floor and as been glued into place

thankyou bob

[heathfield]

All wood has a moisture content. By sticking the flooring to the concrete, the moisture on the top side of the oak is evaporating, but the only way the moisture on the bottom side can evaporate is through the 20mm of the wood itself. The upper drier side will be shrinking as it loses moisture, while the lower side isn't. That causes the warping, and is the reason why flooring should be stacked in a free air circulation in the environment in which it's to be used.
Your answer is to wait until all warping has ceased, and only then have the floor sanded flat

[buildersmate]

I know it is shutting the stable door etc, but this should have been done by a fitter familar with wood floor characteristics - not a carpenter. I hope these planks are not too wide - if greater than 180mm wide you may never get it reasonably flat - even if you get involves in sanding/ refinishing.
For others thinking of doing this, a better solution tis to consider using engineeried boards, which have a thick laminate layer of oak on top.

[Pharlap]

I also wounder if the expansion gap was left around the edges?

[buildersmate]

You don't glue it together, but you can glue it to the floor. A flexible one-part adhesive is used.