Underfloor heating works well beneath wooden floors, but wood is not the easiest covering to heat. The difference between a floor that performs for decades and one that cups, gaps, or splits comes down to decisions made before installation rather than to the heating system itself.
This guide covers what makes wood behave the way it does over heating, which constructions and species suit it, the temperature limits that must be respected, and the installation requirements that determine whether the result lasts. If you are still deciding whether to combine the two at all, our article on the benefits of underfloor heating for wooden floors covers the case for it.
Why Wood Behaves Differently Over Heating
Wood is hygroscopic, meaning it absorbs and releases moisture from the surrounding air continuously. As it takes on moisture it swells; as it dries it shrinks. That movement never stops, and it is the single fact that governs everything about heating a wooden floor.
Underfloor heating affects this in a way many people get backwards. Warming a floor lowers the relative humidity of the air around it, which draws moisture out of the timber. The wood shrinks, and the visible result is gaps opening between boards during the heating season.
The correction worth making. Excessive floor temperature does not raise humidity in the room. It does the opposite: it dries the air and the timber, causing shrinkage, gapping, cupping, and in severe cases splitting or delamination. That is why the temperature limit on a wooden floor is a genuine constraint rather than a cautious recommendation, and why room humidity should be monitored alongside floor temperature.
The practical implication is that a wooden floor over heating needs three things controlled together: the surface temperature, the moisture content of the timber at installation, and the relative humidity of the room during operation. Getting one right and neglecting the others produces the same failures.
Construction Matters More Than Species
This is the point most often missed, and it is more consequential than any list of recommended timbers.
Engineered wood
Engineered flooring has a plywood or cross-laminated core with a solid timber wear layer bonded on top. Because the core layers run in alternating directions, movement in one layer is restrained by the layers around it, which makes the board far more dimensionally stable than solid timber.
For underfloor heating, this is the recommended construction and it is not a close comparison. An engineered board moves a fraction of what a solid board of the same species does under identical conditions, and it also transfers heat slightly better because the core is thinner and denser than solid timber of equivalent thickness.
Solid hardwood
Solid timber can be used over underfloor heating, but it demands considerably more care and carries more risk. It moves more, responds faster to humidity change, and is less forgiving of any error in moisture content or temperature control.
Where solid timber is used, board width and thickness matter substantially. Narrower boards move less in absolute terms than wide ones, because the same percentage of movement across a smaller dimension produces a smaller gap. Thinner boards also transfer heat better and store less. Wide, thick solid boards are the highest-risk combination.
| Factor | Engineered | Solid hardwood |
|---|---|---|
| Dimensional stability | High, cross-laminated core | Lower, moves with humidity |
| Suitability for UFH | Recommended | Possible with strict control |
| Heat transfer | Slightly better | Slightly worse at equal thickness |
| Board width tolerance | Wider boards acceptable | Narrower boards strongly preferred |
| Risk of cupping or gapping | Low when correctly installed | Higher |
| Refinishing | Limited by wear layer thickness | Multiple times possible |
Choosing the Timber
Species does matter, but as a secondary factor after construction. What distinguishes one timber from another is its movement coefficient, meaning how much it expands and contracts for a given change in moisture content.
Species generally considered suitable
Oak, particularly white oak and especially quarter-sawn, is the most widely used timber over underfloor heating. It is stable, strong, and available in engineered form from most manufacturers. Quarter-sawn boards move less across their width than plain-sawn, which is why they are preferred where movement matters.
Teak is highly stable and resistant to moisture change, with natural oils that help protect the timber. Its fine grain and colour make it a premium choice, and it performs well over heating.
Merbau has high resistance to moisture and good dimensional stability, with a dark colour and strong grain. It is durable and suits heated installations.
Walnut is stable and popular for its colour, performing reliably over heating in engineered form.
Species requiring more caution
Being straightforward about this matters, because it affects the specification directly.
Maple and beech are frequently listed as less suitable for underfloor heating despite their strength and appearance, because both have relatively high movement coefficients and respond more sharply to changes in humidity. Where they are used, engineered construction and strict humidity control become essential rather than advisable.
Very dense exotic species can also be problematic, since higher density generally means greater thermal resistance and slower heat transfer, which forces the system to run warmer.
The decisive check. Rather than relying on general species guidance, confirm that the specific product is approved by its manufacturer for use over underfloor heating, and obtain the maximum surface temperature they permit. Flooring manufacturers publish this because they know their own product, and installing outside that specification voids the warranty. Where a manufacturer will not state a limit, treat that as an answer in itself.
Temperature: The Critical Limit
Every wooden floor over heating has a maximum surface temperature, and it is lower than tile permits.
The commonly applied figure is 27°C at the floor surface, though some products specify lower. Exceeding it dries the timber beyond the range it was manufactured for, and the consequences are cupping, gapping, splitting, or in engineered boards delamination of the wear layer from the core.
Why this makes a floor sensor essential
A thermostat controlling only room air temperature has no knowledge of what the floor surface is doing. On a cold day with high heat demand, it will keep calling for heat, and the floor can exceed its limit while the room is still below target.
The solution is an external floor probe connected to the room thermostat. Better thermostats run both sensors simultaneously, controlling room air temperature while independently capping the floor surface. If the floor reaches its limit, the thermostat closes the circuit regardless of what the air temperature says.
For a wooden floor this is not an optional refinement. It is the component that prevents the most expensive failure mode.
The efficiency consequence
Wood adds thermal resistance between the heating element and the room, which means the system must run at a higher water temperature to deliver the same output than it would under tile.
Where the heat source is a heat pump, that matters financially. A heat pump producing 35°C water achieves a considerably higher coefficient of performance than the same unit producing 45°C, so the covering choice affects running cost for the life of the installation. Wood is entirely workable with a heat pump, but the system should be designed around the higher flow temperature from the outset rather than discovering the shortfall after commissioning.
This also means insulation beneath the pipes matters more, not less, with a wooden floor, since the output ceiling is lower and every unit of heat escaping downward is one the floor cannot deliver upward.
Moisture Content and Acclimatisation
Two requirements that installers take seriously and owners often do not realise exist.
Moisture content at installation. Timber for a heated floor should be supplied at a moisture content appropriate to a heated environment, typically lower than for an unheated one. Wood installed too wet will shrink substantially once the heating operates, and gaps that appear in the first season are usually traceable to this.
Acclimatisation. The flooring should be allowed to reach equilibrium with the conditions of the room before installation, in the room where it will be laid, with the heating system already commissioned and running at normal operating temperature. Acclimatising in an unheated room and then switching the heating on afterwards defeats the purpose entirely.
The screed must be dry. Residual moisture in a new screed will migrate into timber laid over it. The screed’s moisture content should be measured rather than estimated, and the heating system used to dry it through a controlled commissioning cycle before the flooring goes down.
Installation Requirements
The commissioning heat-up
New screed must cure fully, then be brought up to temperature gradually before any flooring is laid. Starting at a low flow temperature and raising it in stages over several days dries the screed in a controlled way and reveals any problem while it is still cheap to address.
Turning the system straight to full temperature cracks the screed, and any floor bonded or laid over a cracked screed inherits the problem. Follow the screed manufacturer’s schedule and keep the record, since many warranties require documented evidence that it was followed.
Expansion gaps
A wooden floor must be able to move. Perimeter expansion gaps around the room and at every fixed obstacle allow the boards to expand without pressing against walls. Where they are omitted or filled, the expansion has nowhere to go and the floor lifts or buckles.
Fixing method
Floating installation over an underlay is common and allows the floor to move as a unit. Where boards are bonded to the screed, a flexible adhesive rated for underfloor heating is required, since standard adhesive cannot accommodate the repeated thermal cycling. Mechanical fixing through the screed is not compatible with underfloor heating, for the obvious reason that a nail or screw may find a pipe.
Underlay selection
Underlay adds thermal resistance, and a thick insulating underlay chosen for comfort or sound reduction can substantially reduce the heat reaching the room. Use only an underlay rated for underfloor heating with a low thermal resistance value, and confirm the combined resistance of underlay plus flooring against the system design.
Operating a Wooden Floor Correctly
Maintain room humidity. Timber is comfortable in a relative humidity range broadly matching what people find comfortable, and problems arise at the extremes. Very dry air during the heating season causes shrinkage and gapping. A humidifier in a particularly dry climate, or simply monitoring humidity with an inexpensive meter, prevents the most common seasonal complaint.
Change temperature gradually. Rapid temperature swings stress the timber more than a steady higher temperature does. This suits underfloor heating anyway, since its thermal mass favours steady operation with modest setbacks rather than deep on-off cycling.
Start the season gently. Rather than switching the system to full output on the first cold day, raise the temperature over several days at the beginning of each heating season. This allows the timber to adjust rather than being shocked.
Expect some seasonal movement. Small gaps appearing in winter and closing in summer are normal behaviour for a wooden floor, not a defect. What is not normal is cupping, permanent gapping, or boards lifting.
Safety Considerations
Professional installation. Poor installation causes deformation, cupping, or cracking of the timber, and the errors are largely irreversible once the floor is down. This is not a stage to economise on.
Correct timber selection. Not all wood suits heating. Choose products with good dimensional stability, verified as approved by the manufacturer for underfloor heating rather than assumed suitable.
Temperature control. Regulate the system carefully and use a floor sensor to cap surface temperature. Excessive temperature damages the timber and, over time, can affect adhesives and finishes as well.
Regular inspection. Check periodically that the system is functioning correctly and that the floor shows no signs of movement beyond normal seasonal change. Verify the delivered flow temperature annually against the commissioning record, since a mixing valve that has drifted upward will exceed the floor’s limit without any obvious warning.
“The mistake I see most often with wooden floors is that everyone focuses on which species to buy and nobody asks about the floor sensor. A thermostat measuring room air has no idea what the floor is doing. On a cold day it keeps calling for heat, the room is still below target, and the floor quietly goes past the temperature the flooring manufacturer allows. Six months later the boards have cupped and the customer blames the wood. Fit a floor probe, set the limit to whatever the flooring manufacturer states, and the most expensive failure mode is removed. It costs very little compared with replacing a floor.”
— Maggie Shen, Director of Legom
Components for a Wooden Floor Installation
A hydronic system beneath timber needs the same components as any underfloor installation, with two specifications that matter more than usual.
The thermostat must support a floor probe, ideally running internal and external sensors simultaneously so room air temperature is controlled while the floor surface is independently capped. And the mixing valve must hold its set point reliably, since drift upward directly threatens the floor.
Warm water reaches a manifold that distributes it between individual floor heating pipe loops, each controlled by a thermal actuator responding to its zone thermostat. Our guides to underfloor heating sensors and mixing valves cover both components in detail.
Legom manufactures the complete chain at its facility in Jiaxing, Zhejiang Province, supplied to partners in more than 90 countries. Contact the technical team to discuss specification for a project involving timber flooring.
Frequently Asked Questions
Can you put underfloor heating under wooden floors?
Yes, and it works well when specified correctly. The key requirements are choosing a dimensionally stable product, preferably engineered rather than solid construction, respecting the maximum surface temperature the flooring manufacturer specifies, installing at the correct moisture content after proper acclimatisation, and fitting a floor sensor so the surface temperature is capped independently of room air temperature. Wood is more demanding than tile but entirely workable.
Is engineered wood better than solid wood for underfloor heating?
Substantially, and the difference is not close. Engineered flooring has a plywood or cross-laminated core with a timber wear layer, and because the core layers run in alternating directions, movement in one is restrained by the others. An engineered board moves a fraction of what solid timber of the same species does under identical conditions. It also transfers heat slightly better. Solid timber can be used but demands stricter control of moisture, humidity, and temperature.
What is the maximum temperature for a wooden floor?
Commonly 27°C at the surface, though some products specify lower, and the flooring manufacturer’s stated figure always takes precedence. Exceeding it dries the timber beyond its designed range, causing cupping, gapping, splitting, or delamination of engineered wear layers, and it typically voids the warranty. This is why a floor sensor is essential rather than optional: a thermostat measuring only room air has no knowledge of what the floor surface is doing.
Which wood species work best with underfloor heating?
Oak, particularly white oak and especially quarter-sawn, is the most widely used. Teak, merbau, and walnut also perform well, with teak and merbau offering good moisture resistance. Maple and beech are generally considered less suitable because both have relatively high movement coefficients and respond sharply to humidity change. Whatever the species, confirm the specific product is approved by its manufacturer for use over underfloor heating rather than relying on general guidance.
Why do gaps appear between my floorboards in winter?
Because heating lowers the relative humidity of the air, which draws moisture out of the timber and causes it to shrink. Small gaps appearing during the heating season and closing again in summer are normal behaviour for a wooden floor rather than a defect. What is not normal is cupping, permanent gapping, or boards lifting. If seasonal gapping is pronounced, monitor room humidity and consider a humidifier, and check that the floor temperature is not exceeding its limit.
Do I need a floor sensor with a wooden floor?
Yes, and it is the single most important control component in this application. A thermostat measuring only room air temperature will keep calling for heat on a cold day, and the floor surface can exceed its limit while the room is still below target. An external floor probe allows the thermostat to cap surface temperature independently. Better thermostats run both sensors simultaneously, controlling room comfort while protecting the floor. This costs very little against the price of replacing a damaged floor.
Does wood reduce underfloor heating efficiency?
It adds thermal resistance compared with tile, which means the system must run at a higher water temperature to deliver the same output. With a heat pump this affects running cost, since efficiency rises as flow temperature falls. Wood remains entirely workable, but the system should be designed around the higher flow temperature from the start rather than discovering the shortfall after commissioning, and insulation beneath the pipes matters more because the output ceiling is lower.
How should wooden flooring be acclimatised?
In the room where it will be laid, with the heating system already commissioned and running at normal operating temperature, until the timber reaches equilibrium with those conditions. Acclimatising in an unheated room and switching the heating on afterwards defeats the purpose entirely, since the wood will then dry and shrink after installation. The screed must also be verified dry by measurement rather than estimation before the flooring goes down.
What underlay should I use?
Only one rated for underfloor heating with a low thermal resistance value. Underlay adds resistance between the heating element and the room, and a thick insulating product chosen for comfort or acoustic performance can substantially reduce the heat reaching the space. Confirm the combined thermal resistance of underlay plus flooring against the system design, since the heat loss calculation assumed a particular figure and exceeding it means the floor cannot deliver its designed output.
Reviewed by Maggie Shen, Director at Legom, on August 10, 2026. This guide to underfloor heating for wooden floors was reviewed for technical accuracy, including the relationship between floor heating and timber moisture content, surface temperature limits, and the role of floor sensing in protecting the covering.