Underfloor Heating & Broadleaf Wood Floors

Despite the concerns expressed by those with less expertise, Broadleaf wood floors are successfully fitted over underfloor heating everyday.

We are confident that if you choose a suitable product and and follow our simple guidelines below alongside the rest of our installation guide, you can successfully combine Broadleaf wood flooring with underfloor heating.

System Temperature

The first and most important step is to make your underfloor heating supplier aware that you intend to fit wood flooring over their system and that it needs to be designed so that the temperature under the boards will never exceed 27°C.
 
In our experience the best way to ensure this is with a floor thermostat, which has 27°C as the maximum and shuts the system down if for any reason it is reached. To do this they will need to override any air thermostats that might also be part of the system. Floor thermostats are not expensive and provide a reassuring back up that protects the floor if for any reason the maximum floor temperature is reached.

Product

Next, you need to choose a product that is suitable for use over underfloor heating. Within the Broadleaf range this shouldn't limit you as most of our floors have several compatible options. For details check either the UFH column in the pricing tables on our product pages or our flooring selector.
 
Please note that solid plank floors marked as suitable for underfloor heating will need to be rekilned for this purpose and that there is a small additional charge for this which will be shown separately on your invoice. 

Site Preparation

As with any other installation, first make sure that the site and subfloor meet the basic criteria laid out in the Site Preparation section of our installation guide.
 
The underfloor heating must then be run for 3 weeks before the timber is delivered. Set the thermostat to normal room temperature unless the ambient temperature is too high for this to activate the system. In this case, raise the thermostat temperature so that the heating comes on to warm the room. Although this may cause some discomfort in the summer months it is vital to ensure the evaporation of latent humidity that might otherwise be absorbed by the floor at a later date. 
 
At this stage, if you have a water system, make sure that the water temperature at the manifold is set to the specified temperature (this is normally 40°- 45°C for wood floors but check with your supplier). In all systems make sure that the floor thermostat (see System temperature section above) has been set to be master (overriding any air thermostat) and with a maximum of 27°C.  
 
Timber should then be acclimatised as normal with the heating set at normal room temperature.

Fixing Methods For Water Systems Set In Screed

Broadleaf 105mm & 150mm Solid Oak Flooring that has been re-kilned or Strata Engineered Oak Flooring can be nail fixed over water underfloor heating systems set in screed.
 
To do this either battens will need to be set into the screed, or it will need to be overlaid with tongue & grooved 18mm ply. Inset battens will need to be notched to allow the pipe to run across the floor and must sit at least as high as the surface of the screed. If you require further guidance on setting battens into a screed, please contact our technical team
 
Broadleaf 105mm Solid Oak Flooring that has been rekilned, Essentials & Strata Engineered Oak Flooring and Solid Oak Parquet can be glue fixed over water underfloor heating systems set in screed
 
To glue fix planks and Vintage Oak Parquet, use Broadleaf Ultra Adhesive and then proceed as normal. To glue fix Traditional Oak Parquet, fit using Broadleaf Ultra Adhesive as normal, then undercoat with the desired finish and leave with the heating running normally for a period of 3 weeks so that any initial settling movement can take place before filling, sanding and finishing as normal. 
 
Essentials & Strata Engineered Oak flooring can also be floated using a compatible underlay. We recommend Silent Gold which has low thermal resistance but you should discuss this with your underfloor heating supplier as it is slightly less efficient than glue fixing.

Fixing Methods For Dry Water Systems

Where a water system is set between joists with conductor plates to transfer the heat, or into a floating timber subfloor, you will need to overlay with 18mm tongue and grooved before the flooring is laid to prevent ‘hotspots’ and abnormal shrinkage. 
 
Broadleaf 105mm & 150mm that has been re-kilned and Strata Engineered Oak Flooring can then be nail fixed to this as normal.
 
Essentials & Strata Engineered Oak Flooring and Parquet Oak Flooring can be glue fixed as for systems set in screed above.
 
Essentials & Strata Engineered Oak Flooring can also be floated using a compatible underlay. We recommend Silent Gold which has low thermal resistance but you should discuss this with your underfloor heating supplier as it is slightly less efficient than glue fixing.

Fixing Methods over Electric Systems

Electric underfloor heating systems are most commonly supplied in mat format.
 
To glue or nail fix wood flooring over these you will first need to either overlay them with 18mm tongue & grooved ply or a 12mm latex screed (if this is compatible).
 
Broadleaf 105mm & 150mm Solid Oak Flooring that has been re-kilned, Essentials & Strata Engineered Oak Flooring can then be nail fixed to this as normal. Essentials & Strata Engineered Oak flooring and Parquet Oak Flooring can then be glue fixed as for water systems set in screed above.
 
Alternatively you can float Essentials & Strata Engineered Oak flooring over elecric underfloor heating systems using a compatible underlay. We recommend Silent Gold which has low thermal resistance.
 
Please note that the underlay cannot be in direct contact with the heating elements, so these will either need to be completely enclosed (by a protective foil or mesh) or covered by a thin latex screed.
 
Also, if you intend to overlay a system with 18mm ply, or a latex screed and this is not part of the standard floor construction recommended by your underfloor heating supplier, please make them aware of this and ensure that you understand any implications for the performance of the heating system. 

Running the Heating

The night before your wood flooring is installed, turn the thermostat down so the underfloor heating isn't actually warming the surface of the floor and maintain this status whilst the flooring is fitted. 
 
Once fitting is complete, increase the thermostat temperature by 1°C per day until you reach normal running temperature. Thereafter, ensure that temperature changes are gradual.

Additional Advice

The guidance above is based on considerable experience over many years and ongoing liaison with the key underfloor heating suppliers. However, underfloor heating is still an evolving industry so if you are looking to use a system that is not covered above, or you receive apparently conflicting advice from your underfloor heating supplier, please get in touch so that we can help you with specific advice. 

Equally, should you have other any specific queries about wood flooring and underfloor heating, or our guidance above please contact our technical team.
 
Telephone: 01269 851 987 or email: technical@broadleaftimber.com
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