Despite the concerns sometimes expressed by those with less experience in this area, with the right preparation and the right product, it is possible to lay solid wooden flooring over all types of underfloor heating successfully.

Broadleaf have developed the following basic guidelines as a result of considerable experience over recent years and, if you do plan to fit a solid wooden floor over underfloor heating, we would recommend that you take 5 minutes to study them:

1) Not all types of timber are suitable for use over underfloor heating.

In our opinion Oak can be used successfully , but must be re-kilned to 6 - 9% humidity. Drying the timber to this level is designed to prevent the close proximity of the heat from the underfloor heating shrinking / warping the boards once the floor has been laid. (Normally boards are only kilned to 9 - 12%). Re-kilning takes place prior to the machining of the timber into boards, so can generally only be offered by manufacturers of timber flooring.

Nu-Heat customers receive FREE re-kilning at Broadleaf, please mention Nu-Heat when you call.

Some manufacturers are happy for their Oak flooring to be used over underfloor heating without being re-kilned. They will normally require that it be loose laid for anything from 4-8 weeks in the hope that any shrinkage takes place before fixing and will rarely take responsibility if the boards continue to shrink after fitting. We do not consider this to be anywhere near as effective as re-kilning.

We also consider our unfinished and pre-finished Chestnut boards suitable for use over underfloor heating.

Due to their particular structure and dimensions these remain stable in close proximity to underfloor heating without the need for re-kilning. Please note however that these products are not suitable for high traffic areas.


2) We do not recommend that you fit boards in excess of 150mm wide over underfloor heating, or that you use boards of rustic grade or exotic timber.

This is because the heat at close proximity will encourage any boards natural tendency to move and warp and whereas narrower, higher grade boards from inherently stable timbers should resist this, it is very unlikely that wider boards, very knotty boards or exotic timbers such as Teak, Jarrah or Elm would do so.

3) As with any concrete screed, one that is to take underfloor heating needs to properly dry before timber flooring is installed above it.

In addition to this, where a screed contains heated elements, these should have been on at a low but constant level for at least 2-3 weeks before a wood floor is fitted. This is because, once heated, the concrete loses a further 5% of its latent humidity and must be given the chance to do so before the floor is laid over it.

Failure to do this is likely to lead to over-expansion once the heat is switched on and the moisture begins to evaporate into the floor.

Do not try to speed up this process by turning the heating up high.

4) Once the heat has been switched on for the required period (and not before), the timber must be stored for a further week in the room where it is to be fitted so that it can acclimatise.

It is important that boards are stacked to facilitate airflow around them 'criss cross fashion is ideal. If all of the boards are tightly packed, only the outer boards will acclimatise.


Call: 01269 851 910

http://www.broadleaftimber.com