Underfloor Heating

There are two main structural options to consider before choosing which type of wood flooring to lay over your under floor heating either solid wood or engineered wood, some companies will say that if hardwood is re kilned to a lower moisture content this will be successful. At Trunk we do not agree, wood is a hydroscopic material and so will expand and contract. In homes with conventional heating systems wood will expand in summer and contract in winter; however the movement in humidity and moisture is not as great as where under floor heating is involved. In normal conventionally heated homes the wood will reach what is known as equilibrium moisture content, which is a moisture content at which it can live at for the rest of its life give or take slight seasonal changes. However with under floor heating these seasonal changes are magnified by the heat directly underneath the boards. Hence the introduction of the TRUNK engineered Plank.

Traditional engineered boards have a softwood core and are resistant to movement under normal conditions. TRUNK engineered flooring has a unique structure; layers of water-resistant first grade birch hardwood are glued together in opposing directions to form a 15mm multilayer fully stable and structural base , on top you have a 6mm hardwood layer of your choice. This gives not only the appearance and the durability of a solid wide hardwood board from 5” up to 8 ½” and the lengths and 8’ and 10’ with a small percentage of shorter lengths due to defect cuts, But ensures even better stability than a traditional engineered board. In addition the boards can be unfinished, pre-finished either matt or gloss, smoked, limed, charcoaled or matched to a picture in a book!!! ( the advantage of buying from source!!) . We can also supply these boards with an oiled finish if required. TRUNK engineered flooring has been successfully used in many situations where different types of under-floor heating have been used and is extremely resistant to movement. TRUNK boards can be glued directly to screed floors (using SIKABOND glues) or secret nailed to battens (please see fixing below)

If a concrete screed has been used then gluing boards using either SIKABOND T54 or T52 is the best method to ensure a rapid heat transfer. (Any layer of air left when using ‘floating’ boards will act as barrier to the heat transfer – this is another reason why traditional engineered boards are not as suitable for under-floor heating, as they are usually laid as a ‘floating floor’.)

Fixing The Boards

We would recommend either secret nailing or gluing boards depending on the method of under-floor heating. If battens have been laid then the flooring can be secret nailed to this but great care must be taken around any areas close to the pipes. It may be advisable to use the SIKABOND T2 glue (supplied in cartridges) to glue boards to any battens that are close to pipes to ensure that there is no damage to the pipes from nails.
Any resultant water leaks from pipes are disastrous!

FLOATING FLOORS: Although TRUNK flooring can be laid as a 'floating floor' (ie where the joints are glued together to form a 'skin' over the sub-floor, but is not fixed down directly to the sub-floor). We do not normally recommend this type of fitting over underfloor heating due to the possibility of air gaps above the sub floor which can have a detrimental effect on the heat conduction.