As winter sets in you may be seeing more clients looking to underfloor heating (UFH) options to take the edge off that early morning chill. Effective, efficient and low maintenance, UFH is becoming an increasingly popular specification in both new builds and more intensive renos, and the good news is that it pairs beautifully with engineered timber flooring.
With that said, integrating UFH requires some specific design considerations that are critical to ensure long-term performance, minimise risks, and maintain warranty coverage. The Forté Timber Overlay Flooring System outlines key guidelines for designing and installing UFH under engineered timber floors, and we’ve summarised the key points here.
A fundamental requirement is that the underfloor heating system must cover the entire area beneath the timber flooring. Partial coverage can lead to uneven expansion and contraction. If full coverage isn't feasible, carefully planned separation and expansion zones may be acceptable but should be discussed with the supplier beforehand.
To prevent "hot spots," it’s essential to ensure consistent spacing and positioning of pipes or cables within the slab or screed. Every heated room should also include a dedicated probe to regulate surface temperature and ensure it does not exceed 27°C – key threshold for maintaining the structural integrity of timber flooring.
Not all UFH systems are suitable for engineered timber. Forté recommends using hydronic (water-based) or in-screed electric systems, both of which should maintain a maximum surface temperature of 27°C. "Electric blanket" systems and exposed hydronic systems are not recommended, as they lack the necessary stability and can create thermal shock conditions that damage timber.
Installers must have experience working with timber flooring to avoid complications. Additionally, the heating system must be operational and tested for at least three weeks prior to floor installation. This allows the substrate to stabilise and be properly prepared.
A gradual commissioning process is vital. For both hydronic and electric in-screed systems, increase the heating temperature in 5°C increments up to 27°C, then hold for 48 hours. Cool down in similar 5°C increments. This procedure helps acclimatize the flooring system and avoid thermal stress.
Hydronic systems should maintain pipe spacing no greater than 150mm, with a recommended concrete slab coverage of 60mm (minimum 30mm) above the tubes. For in-screed electric systems, at least 8mm of screed must cover the heating cables.
Before floor installation, the heating should be gradually increased to 15°C and held at that temperature for 48 hours post-installation. Keeping the system running year-round helps avoid seasonal swelling or shrinkage of the timber, which can lead to visible gaps or warping.
Avoid placing heavy rugs or furniture directly on heated floors, as trapped heat may cause surface cracking, cupping, or finish breakdown. Temperature changes should always be gradual – adjust in 2°C increments per day to minimise thermal shock.
If you need further clarification or want to discuss a specific project, Forté’s technical team is always available to assist.