How to Install Underfloor Heating With Wooden Flooring: An Expert Step-By-Step Guide
Wooden floors remain popular among homeowners. With various grains, tones and finishes, floorboards are versatile enough for everything from neutral to statement flooring. Their versatility, durability and timeless look make wooden floorboards a firm favourite among homeowners, property developers and renovators alike.
In this expert guide, we will address which types of wooden flooring and underfloor heating should be used for the best results and provide a detailed guide on preparing, installing and maintaining underfloor heating with wooden floorboards.
Our step-by-step Guide will cover:
- Materials and pre-installation preparations
- Assessing and preparing the subfloor surface for UFH
- Installing the underfloor heating system
- Installing wooden flooring over underfloor heating
- Post-installation care and initial heat-up
Stage 1: Materials and pre-installation preparations
Before beginning the installation, ensure you have all the appropriate materials for installing underfloor heating with wood flooring. There is a wide range of wooden flooring, insulation, and underfloor heating systems. We have guided you through the key considerations and recommended products when installing underfloor heating with wood flooring; however, it is imperative that you always check manufacturer guidelines to ensure any materials or systems you use are compatible.
+ Which wood flooring is best for use with underfloor heating?
Due to its natural properties, wood physically responds to varying heat and moisture levels, which can lead to warping in extreme cases. However, these properties vary across different wood species and can be altered through various manufacturing processes. Selecting a wood with optimal properties for underfloor heating will reduce the risk of warping and maximise the efficacy of the heating system. There are two main categories of wooden flooring: engineered wood and solid wood.
– Engineered Wood: Engineered wood is the best choice for use with underfloor heating. Engineered wood features a top layer of solid wood underpinned by a core of softwood or medium-density fibreboard (MDF). MDF is a manufactured wood that is free of the naturally occurring natural defects found in solid wood, making it a better conductor of heat. Engineered wood has enhanced stability; the softer core material allows for thermal expansion, protecting the solid wood surface from distortion. The solid wood veneer means you can still enjoy the visual appearance of your desired wooden flooring without compromising on the efficacy of your underfloor heating and reducing the risk of warping.
– Solid Wood: If you are committed to solid wood floors, there are options that are compatible with underfloor heating. Different wood species vary in porosity and density, affecting their suitability. For example, oak is a medium to high-density wood with some flexibility for movement. Oak is known for staying moisture-free, making it a suitable choice for use with underfloor heating. Solid wood floorboards have higher thermal resistance than other materials, so avoid floorboards thicker than 18mm to minimise the impact on the efficacy of the heating. Wider boards are more prone to warping, so we recommend going for floorboards narrower floorboards with a maximum thickness-to-width ratio of 1:10 (for example, a floorboard 16mm thick and 160mm wide would be suitable). Solid wood must be appropriately dried and manufactured for use with UFH, so it is imperative to check that any solid wood used is approved for use with UFH.
+ Selecting the right underfloor heating system to use with wood flooring
To get maximum heating efficiency with wooden flooring, we recommend using an underfloor heating system with aluminium foil plates. The highly conductive properties of aluminium facilitates the even distribution of heat. This effectively counters the lesser conductive properties of wood, allowing for optimal heating even with wooden flooring. Ambiente provides a wide range of such systems. When choosing the right underfloor heating system, it is essential to consider several factors, such as space, subfloor structure, accessibility, and time. We have outlined some of our top choices of underfloor heating for use with wooden flooring.
Our OverPlate® / UnderPlate® underfloor heating range has been specially designed for suspended floors in retrofit and new build projects. Our OverPlate® / UnderPlate® systems are designed to fit within the void of suspended floors, eliminating any bulky floor build-up. All OverPlate® / UnderPlate® systems feature an aluminium surface plate to maximise heat transference and distribution. Even heat distribution minimises the chance of floorboards distorting or warping, while maximum transference will allow for faster room warming. Our OverPlate® / UnderPlate® is available in several variations to suit different build requirements.
AmbiFloat wet underfloor heating systems feature the same aluminium plates in addition to pre-grooved high-density insulation panels. These high-performance panels provide additional structural support and prevent downward heat loss. With a heat output of up to 80 W/m2, even heat distribution and supreme insulation all rolled into one, AmbiFloat is the optimal UFH choice for wood flooring.
If you want to install UFH on a solid structural floor with limited space for build-up, we recommend our AmbiLowboard EPS. Part of our low-profile underfloor heating range, the AmbiLowboard is lightweight, easy to install, and ultra-slim for minimal floor build-up. The low-profile design features pre-grooved insulation boards covered with a foil layer for optimal heat distribution. Some wood flooring can be directly laid over this system; however, always check with the flooring manufacturer’s guidelines.
Other underfloor heating systems from our low-profile range that are compatible with wooden flooring include our AmbiDeck and AmbiSolo systems.
+ Choosing the right insulation for optimal underfloor heating
Because wood flooring is not the best conductor of heat, it is vital to minimise downward heat loss with appropriate insulation. This maximises heat pushed upwards through the floorboards for efficient heating. Insulation is especially important when the UFH is installed over a suspended subfloor.
– Mineral Wool: Mineral wool is made from fibres spun from heat-resistant materials such as stone and silica. It provides highly efficient thermal insulation and acts as an acoustic barrier. ideal for insulating suspended floors when installing UFH systems such as OverPlate® / UnderPlate®.
– Expanded Polystyrene Insulation Boards: High-density insulation boards provide efficient insulation and aid structural integrity. Both our AmbiFloat and AmbiLowboard UFH systems use expanded polystyrene insulation panels. Due it is sometimes possible to lay tongue-and-groove floorboards directly over these systems. However, it is always important to check manufacturer guidelines.
+ Temperature control for UFH installation with wood flooring
Precise and accurate temperature control is essential to prevent rapid or excessive heating and cooling floorboards. We recommend the AmbiEgo Actuator for use with wood flooring. This intelligent actuator maintains highly precise temperature regulation and efficient heat distribution, protecting your floorboards and providing maximum comfort.
Stage 2: Assessing and Preparing the Subfloor Surface for UFH
Subfloor preparation will vary greatly depending on the type of subfloor surface being worked with and the type of underfloor heating system being installed. This guide provides a general overview of two main subfloor types: suspended timber subfloors and solid subfloors.
– Preparing suspended timber subfloor: There are a number of requirements that must be checked before installing underfloor heating into a suspended subfloor. Click here to read the Installing within a suspended timber floor guide.
– Check the moisture content: To withstand UFH, the moisture content of the structural timber must be less than 10% and ideally lower than 8%.
– Checking structural integrity: If retrofitting an old suspended floor, check for rotting or damaged joists and make sure these are replaced before starting. The joists should be level with no curvature. Uneven or warped joists will cause complications when installing underfloor heating and flooring.
– Ensure the suspended floor is appropriately insulated: If the suspended subfloor is not already insulated, use a minimum of 100mm of mineral wool between the joists fitted directly beneath where the UFH system will be installed. The insulation and UFH should be in direct contact to prevent air pockets.
– Fixing in support battens: For insulated boards such as AmbiFloat 30, timber battens must be fixed to the side of the joists at the required depth to support the insulation boards.
– Preparing solid subfloor for UFH: A solid concrete subfloor must be perfectly level and fully cured. Any flaws can lead to poor heat distribution and complications when laying floorboards.
– Check moisture levels: Freshly laid concrete should have moisture levels below 2-3% and air humidity below 35%.
– Ensure the subfloor is level: If the floor is uneven, use a levelling compound such as AmbiFibre Pro to level the floor. AmbiFibre Pro also has excellent insulative properties, further reducing downward heat loss.
– Seal with a damp-proof membrane (DPM): If you are laying insulation boards directly on a subfloor, or mineral wool directly on a subfloor between battens, we advise sealing the subfloor with a DPM to prevent moisture from travelling up and damaging the UFH from underneath.
Before installing the underfloor heating system, always double-check that the subfloor meets the specific requirements laid out by the UFH manufacturer.
Stage 3: Installing the underfloor heating system
Note: This is a general installation guide on best practices for underfloor heating with wood flooring. For product-specific details, our installation guides can be found on our resources page.
For all installations, refer to the design plan drawings and prepare to lay the floor in accordance with the layout described.
+ Fix UFH heating panels in place
– Aluminium diffusion plates on joists: For UFH systems such as Overplate®, the aluminium plates are fixed directly atop the wooden joists or battens. The plates should be fixed so they are in direct contact with the insulative material below.
– UFH insulation panels on joists: For UFH systems like AmbiFloat 30, battens must be fitted between joists at the required depth to support the insulation boards. The pre-grooved insulation boards are then slotted into place between the joists.
– UFH insulation panels on solid subfloor: For UFH systems such as AmbiFloat 10 and AmbiLowboard, the pre-grooved insulation boards are placed directly onto the DPM across the entire floor surface. Use battens where needed for structural support.
+ Install manifold and pipework
This step varies based on the UFH system and designs, so always refer to the supplied designs. Starting at the manifold, lay the pipe according to your design drawing, navigating the most efficient route between the manifold and the zone. Lay the pipe into the pre-grooved boards per your system design drawings. On completion of the loop, connect to the return bar (bottom bar with blue caps). Mark up the manifold tag with the loop length and the room name.
+ Carry out pressure tests and final checks
Filling and flushing the system and pressure tests all before tiling. the underfloor heating must be fully commissioned and tested to ensure there are no leaks. Always refer to the supplied design and manufacturer’s instructions when installing the underfloor heating system.
Stage 4: Installing wooden flooring over underfloor heating
In some cases, tongue-and-groove wood floorboards can be laid directly over Ambiente’s wet underfloor heating systems. However, always check the underfloor heating installation guide and the flooring manufacturer guidelines.
– Installing a structural subfloor (optional): In some cases, a structural subfloor layer (such as a plywood board) must be laid before the floorboards. We recommend bonding any structural subfloor to the UFH system with a suitable adhesive for the best thermal conduction.
– Acclimatising wood flooring: Before fixing down the wooden floorboards, it is crucial to acclimatise them to the environment. This step is imperative to prevent cupping, warping or distortion after installation. The floorboards should be brought into the relevant room, unpackaged, and, if possible, laid out so air can circulate around each floorboard. The floor temperature should be maintained at 15°C during this process, with an ambient room temperature between 15-18°C. Engineered floorboards usually require 48 – 72 hours to acclimatise prior to installation, while solid wood flooring usually requires a minimum of 7 full days.
– Flooring installation: Using a thermal adhesive allows for a more adaptable fit, accommodating the thermal expansion of the floorboards. The glue will also ensure direct contact between the UFH and wooden floorboard, reducing thermal resistance and maximising heat output. When installing the wood flooring, an expansion gap of 10 – 15mm should be left around the entire outer perimeter of the room. This gap will allow sufficient space for the floorboards to expand without becoming distorted. The gap can be hidden with skirting boards if desired. Installation methods may vary depending on the wood used, so always refer to the manufacturer’s installation guide.
installed flooring should usually be given at least 48 hours to settle before beginning the first heating cycle.
Post-installation care and initial heat up
+ Initial floor heat-up with wood flooring
For the initial heat-up, heat the floor temperature no more than 1°C per day until the required temperature is reached. Remember that for most wood flooring, the floor temperature should not be increased beyond 27°C. Heating wood flooring above 27°C can increase the risk of warping or cupping.
+ Maintaining a steady temperature
Try to maintain a steady temperature as much as possible when using underfloor heating with wood flooring rather than switching the system on and off or allowing the system to fully cool. Always avoid rapid warm-ups, as this can damage wood flooring. Underfloor heating thermostats and actuators can help maintain temperatures within a steady range and ensure even heat distribution, protecting your wooden flooring while providing maximum comfort. Avoid using thick rugs or runners, especially those with rubber backing, over wooden flooring, as this can trap heat and cause the floorboards to exceed 27°C.
+ Did you find this article helpful?
How To Install Underfloor Heating On A Concrete Floor
Eco Friendly Heating Systems
+ Any questions on Wooden Floor UFH?
If you would like more guidance on underfloor heating, get expert advice from our team at sales@ambiente.co.uk or by calling 01707 649 118
Customers and contractors want the best for their homes and projects, and our underfloor heating and services will help installers stay ahead of competitors and be ready to seize the opportunity whenever it’s presented.
Ambiente is a supplier that proactively works with installers to provide support and guidance, from pipework specification to design and technical support.
Fill out our form today to start your journey as an Ambiente-affiliated UFH installer.
+ Not an Ambiente accreditied installer yet?
Benefit from a wide range of UFH systems and controls to suit every project, gain project leads from our extensive network of contacts and technical support from a highly knowledgeable expert team.
