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CRAFT Hardwood Guides

Wood Flooring and Underfloor Heating:
What You Need to Know

The facts about installing wood floors over underfloor heating, including what works, what doesn't, and how to avoid problems.

Written by Wojciech, founder of CRAFT Hardwood | Updated February 2025 | 22 min read

"Can I have wood flooring with underfloor heating?"

It's one of the most common questions we hear, and the answer is yes - with the right approach.

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Underfloor heating (UFH) has become increasingly popular in new builds and renovations across Lancashire and Greater Manchester. The appeal is obvious: no radiators taking up wall space, even warmth throughout the room, and lower running costs. But combining UFH with wood flooring requires understanding how heat affects wood and making informed choices about materials and installation.

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After installing numerous floors over underfloor heating systems since 2012, we've learned what works, what doesn't, and how to ensure your heated floor performs beautifully for decades.

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This guide explains everything you need to know about combining wood flooring with underfloor heating.

The Simple Answer

Yes, wood flooring works with underfloor heating, but:

  • Some wood floor types work better than others

  • Installation must be done correctly

  • The UFH system must be commissioned properly

  • Temperature limits must be respected

  • You need realistic expectations about wood movement​

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Get these factors right, and you'll have a beautiful, warm floor that performs perfectly. Get them wrong, and you risk cupping, gapping, or other moisture-related problems.

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How Underfloor Heating Affects Wood

To understand why UFH and wood require special consideration, you need to understand how heat affects timber.

Wood and Moisture Content

Wood is hygroscopic - it constantly exchanges moisture with its environment. It expands when it absorbs moisture and contracts when it loses moisture.

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UFH affects this relationship by:

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1. Heating from below creates upward moisture flow

  • Heat drives moisture out of the wood from the bottom surface

  • This can cause differential moisture content (drier underneath, normal moisture on top)

  • Differential moisture causes cupping (edges higher than centres)

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2. Heating reduces relative humidity

  • Warm air holds more moisture than cool air

  • Heating a room reduces relative humidity

  • Lower humidity causes wood to lose moisture and contract

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3. Temperature cycling affects wood stability

  • Switching UFH on/off dramatically causes expansion/contraction cycles

  • Rapid temperature changes are worse than constant temperature

  • Wood prefers stable conditions

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The key principle: UFH creates a more challenging moisture environment than traditional heating. Wood floors over UFH need to be chosen, installed, and managed more carefully.

Types of Underfloor Heating

The type of UFH system affects how well it works with wood flooring.

Water-Based (Wet) UFH

How it works:

  • Warm water (typically 35-50°C) circulates through pipes in floor

  • Embedded in screed or underneath floorboards

  • Controlled by thermostats and manifold system

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Compatibility with wood:

  • Excellent - the preferred UFH type for wood floors

  • Lower surface temperatures than electric systems

  • More even heat distribution

  • Slower temperature response (gradual changes suit wood)

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Screed depth considerations:

  • Thick screed (65mm+): Excellent thermal mass, very even heat

  • Thin screed (40-50mm): Adequate, slightly less even

  • Low-profile systems (15-20mm): Less thermal mass, more responsive

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This is what we typically work with in new builds and major renovations.

Electric UFH

How it works:

  • Electric heating cables or mats under the floor

  • Quicker to respond than water systems

  • Often used in smaller areas or retrofits

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Compatibility with wood:

  • Acceptable but less ideal than water-based

  • Can create higher surface temperatures (harder to control)

  • Heat is less evenly distributed

  • More prone to hot spots

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Types:

  • Cable systems (embedded in levelling compound)

  • Mat systems (thin, quick installation)

  • Foil systems (very thin, minimal floor height increase)

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Our experience: Electric UFH can work but requires more careful selection of wood flooring and close attention to temperature control.

Best Wood Flooring Types for UFH

Not all wood floors are equally suitable for underfloor heating.

Engineered Oak - The Best Choice

Why engineered works best:

  • Cross-layered construction provides dimensional stability

  • Resists cupping and warping better than solid

  • Thinner profile allows better heat transfer

  • Less movement in response to temperature changes

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Specifications for UFH:

  • Total thickness: 14-20mm (thinner = better heat transfer)

  • Wear layer: Minimum 4mm

  • Core: Birch plywood or spruce (both work well)

  • Installation: Fully glued to subfloor (best heat transfer)

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Our recommendation: 15mm engineered oak with minimum 4mm  wear layer, fully glued installation.

Solid Oak - Can Work But Requires Care

Why solid is more challenging:

  • Moves more in response to humidity changes

  • More prone to cupping over UFH

  • Thicker = reduced heat efficiency

  • Requires more careful selection

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If choosing solid oak over UFH:

  • Thickness: Maximum 18mm (thinner is better)

  • Width: Maximum 120mm (narrower planks move less visibly)

  • Pattern: Herringbone works well (small blocks distribute movement)

  • Species: Oak or engineered exotics (avoid very reactive timbers)

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Our approach: We can install solid oak over UFH, but we're selective about specifications and set realistic expectations about movement.

What to Avoid Over UFH

Poor choices:

  • Very wide planks (180mm+) in solid timber - excessive visible movement

  • Thick solid floors (20mm+) - poor heat transfer, excessive movement

  • Bamboo or certain exotics - some are dimensionally unstable

  • Laminate - often has poor heat conductivity and movement issues

Plank Width and Pattern Considerations

The size and pattern of your floor significantly affect performance over UFH.

Plank Width

Narrow planks (90-120mm):

  • Less visible movement

  • Better suited to solid oak over UFH

  • Any gapping is distributed across more joints (less noticeable)

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Medium planks (130-150mm):

  • Acceptable with engineered

  • Risky with solid oak over UFH

  • Moderate movement potential

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Wide planks (180mm+):

  • Only use engineered oak

  • Avoid solid oak (too much potential movement)

  • Beautiful but needs stability of engineered construction

Pattern Types

Herringbone - Excellent for UFH:

  • Small individual blocks distribute movement

  • Traditional 70mm x 250mm blocks move minimally

  • Even larger herringbone (120mm x 600mm) performs well

  • Gapping less visible due to pattern complexity

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Chevron - Good for UFH:

  • Similar benefits to herringbone

  • Continuous pattern means movement slightly more visible than herringbone

  • Works well with engineered

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Wide planks - Use engineered:

  • Straight-laid wide planks show movement most clearly

  • Essential to use engineered construction for stability

  • Beautiful contemporary look but demands stability

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Our most common UFH installations: 15mm engineered oak herringbone, fully glued. Combines beautiful pattern, stability, and excellent heat compatibility.

Temperature Limits and Control

This is critical - exceed temperature limits and you'll damage your floor.

Maximum Surface Temperature

Absolute limit: 27°C surface temperature (measured at the floor surface)

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Recommended: 23-25°C surface temperature for optimal balance of comfort and floor longevity

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Why limits matter:

  • Above 27°C: Rapid moisture loss, excessive cupping, potential adhesive failure

  • Above 30°C: Severe damage likely, potential finish damage

  • Higher temperatures don't significantly improve comfort anyway

Measuring Surface Temperature

How to check:

  • Use infrared thermometer (£15-30 from DIY stores)

  • Measure floor surface when UFH at operating temperature

  • Check multiple locations (identify hot spots)

  • Do this annually to ensure system is properly calibrated

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What if too hot?

  • Reduce flow temperature at manifold/boiler

  • Adjust thermostats downward

  • Check for system faults (one zone too hot)

  • Better to be slightly cooler than risk floor damage

Flow Temperature vs Surface Temperature

Flow temperature: Temperature of water entering UFH pipes (typically 35-50°C)

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Surface temperature: Temperature at floor surface (typically 23-27°C)

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The relationship depends on:

  • Screed thickness and type

  • Floor covering (wood is insulating)

  • Room temperature and heat loss

  • Outside temperature

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Key point: You control flow temperature, but what matters for the floor is surface temperature. Always verify surface temperature regardless of system settings.

Avoid Rapid Temperature Changes

Wood hates sudden temperature swings.

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Bad practice:

  • UFH on full blast Monday, completely off Tuesday, back on Wednesday

  • Holiday mode: Off for two weeks, then maximum heat on return

  • Summer: Off for 4 months, then sudden restart in October

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Good practice:

  • Keep UFH at minimum 15-18°C year-round

  • Increase/decrease gradually (2°C per day maximum)

  • Never turn completely off for extended periods

  • Smooth, gradual temperature changes

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Why this matters: Rapid temperature changes cause rapid moisture content changes. Wood responds by expanding/contracting quickly, leading to cupping, gapping, or stress damage.

Installation Requirements for UFH

Proper installation makes all the difference.

Commissioning the UFH System BEFORE Installation

This is absolutely critical and non-negotiable.

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Proper UFH commissioning:

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  1. Initial cure (new screed):

    • Allow screed to cure (minimum 4 weeks, ideally 6-8 weeks)

    • Follow screed manufacturer's guidelines
       

  2. Drying phase:

    • Run UFH at gradually increasing temperature

    • Start at 25°C flow temperature

    • Increase 5°C per day until maximum flow temperature reached

    • Maintain maximum temperature for 7 days minimum

    • This drives moisture out of screed
       

  3. Cool-down:

    • Reduce to normal operating temperature

    • Allow system to stabilize
       

  4. Moisture testing:

    • Test screed moisture content before flooring installation

    • Must be below 75% RH (ideally below 70%)

    • If too wet, continue drying phase
       

  5. Installation temperature:

    • Reduce UFH to minimum (15-18°C) for installation

    • Maintain this temperature during installation and finishing

    • Wood acclimatises to normal conditions, not heated conditions

What happens if UFH isn't commissioned properly?

  • Wet screed releases moisture into wood floor

  • Cupping occurs within weeks/months

  • Permanent damage

  • Extremely common problem we see in new builds

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We will not install over improperly commissioned UFH. This is one of our non-negotiable quality standards.

Installation Methods

Fully glued (recommended for UFH):

  • Best heat transfer (no air gap)

  • Most stable (prevents movement)

  • Flexible adhesive allows wood movement while maintaining contact

  • Our preferred method over UFH

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Floating (acceptable for UFH):

  • Acoustic underlay must be suitable for UFH (check thermal resistance rating)

  • Less efficient heat transfer (slight insulating effect of underlay)

  • Easier installation, easier removal

  • Acceptable with engineered floors

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Secret nailed/clipped (avoid over UFH):

  • Air gap reduces heat transfer

  • Only suitable if screed surface unsuitable for gluing

  • Less common with UFH

Expansion Gaps

Standard expansion gaps apply, but may need to be larger over UFH.

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Standard expansion gaps: 10-15mm around perimeter

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Over UFH: Consider 12-15mm minimum (wood experiences more extreme movement)

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Why larger gaps help:

  • UFH causes more expansion/contraction cycling

  • Extra space prevents pressure build-up

  • Reduces risk of buckling during expansion

  • Still hidden under skirting boards

Thermal Resistance and Heat Output

Wood is an insulator - it reduces UFH efficiency slightly.

Thermal Resistance (R-value)

Every floor covering has thermal resistance, which affects how much heat passes through.

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Typical R-values:

  • Ceramic tile: 0.01 (excellent heat transfer)

  • 15mm engineered oak: 0.13-0.15 (good)

  • 18mm solid oak: 0.17-0.19 (acceptable)

  • 20mm solid oak: 0.20+ (reduces efficiency noticeably)

  • Carpet with underlay: 0.20-0.40 (poor)

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What this means: Wood flooring reduces UFH output by roughly 10-15% compared to tile. You may need slightly higher flow temperature to achieve same room temperature.

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Compensating for wood flooring:

  • Slightly higher flow temperature (within limits)

  • Ensure good insulation below UFH (prevents heat loss downward)

  • Proper UFH design accounting for wood covering

  • Accepts slightly reduced output as trade-off for aesthetics

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Bottom line: Wood over UFH works well, just don't expect identical heat output to tile.

Living with Wood Floors Over UFH

Normal Seasonal Movement

Even with UFH, expect some seasonal movement.

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Winter:

  • UFH running consistently

  • Indoor humidity lower (heating dries air)

  • Wood loses moisture, contracts slightly

  • Small gaps (1-2mm) may appear between planks

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Summer:

  • UFH off or minimal

  • Indoor humidity higher

  • Wood gains moisture, expands slightly

  • Gaps close

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This is normal. Well-installed engineered oak over UFH typically shows 1-2mm maximum gap width in winter. Solid oak may show 2-3mm gaps.

Controlling Indoor Humidity

Ideal relative humidity: 45-55% year-round

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Benefits of stable humidity:

  • Minimises wood movement

  • Protects floor and furniture

  • More comfortable living environment

  • Easier to maintain with UFH

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Winter (UFH running = dry air):

  • Use humidifiers if RH drops below 35%

  • Houseplants help naturally

  • Don't over-heat (18-21°C room temperature adequate)

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Summer (UFH off = higher humidity):

  • Use dehumidifiers if RH consistently above 65%

  • Ensure good ventilation

  • Keep UFH at minimum (don't turn completely off)

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Monitoring:

  • Inexpensive hygrometer (£10-20)

  • Check RH weekly

  • Understand your home's patterns

Operating UFH Properly

Daily operation:

  • Set thermostats to desired temperature

  • Let system maintain temperature automatically

  • Don't manually override frequently

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Seasonal changes:

  • Spring: Reduce temperature gradually over 2-3 weeks

  • Autumn: Increase temperature gradually over 2-3 weeks

  • Don't shock the system or floor with sudden changes

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Holiday/away periods:

  • Reduce temperature but don't turn off

  • Maintain minimum 15-18°C

  • Return to normal gradually

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Summer shutdown:

  • Don't turn completely off

  • Maintain 15°C minimum year-round

  • Prevents excessive moisture gain and expansion

Common Problems and Solutions

Problem 1: Cupping (Edges Higher Than Centres)

Cause: Moisture from below (usually wet screed) or excessive UFH temperature

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Symptoms:

  • Board edges curl upward

  • Walking on floor feels uneven

  • Usually appears within 6-12 months of installation

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Solutions:

  • Check surface temperature (reduce if above 27°C)

  • Check screed moisture (may still be drying)

  • Allow floor to dry naturally (can take months)

  • Don't sand until cause resolved and floor stabilized

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Prevention:

  • Proper UFH commissioning before installation

  • Adequate screed drying time

  • Temperature within limits

Problem 2: Excessive Gapping

Cause: Wood too dry when installed, or excessive heat drying wood out

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Symptoms:

  • Gaps of 3-5mm+ between planks

  • Gaps don't close in summer

  • More common with solid oak over UFH

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Solutions:

  • Check surface temperature (reduce if too high)

  • Increase humidity if below 35% RH

  • If gaps persist, may require floor replacement or specialist repair

  • Accept some gapping if within reasonable range (1-3mm)

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Prevention:

  • Proper acclimatisation before installation

  • Install at appropriate moisture content

  • Maintain reasonable humidity levels

  • Choose engineered over solid for better stability

Problem 3: Hot Spots

Cause: UFH pipes too close together or uneven distribution

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Symptoms:

  • Some areas noticeably warmer than others

  • Visible on infrared thermometer

  • May cause localized cupping or damage

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Solutions:

  • UFH system may need rebalancing

  • Check manifold settings

  • May require heating engineer assessment

  • Severe cases might need modified pipe spacing (major work)

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Prevention:

  • Professional UFH design and installation

  • Proper commissioning and balancing

  • Regular system maintenance

Problem 4: Adhesive Failure

Cause: Excessive heat or moisture affecting adhesive bond

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Symptoms:

  • Loose boards or hollow sound when walking

  • Boards can move slightly

  • Usually only with very high temperatures or wet subfloors

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Solutions:

  • Identify and fix cause (temperature or moisture)

  • Affected areas may need re-gluing

  • Severe cases require removal and reinstallation

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Prevention:

  • Use UFH-rated adhesive (specified for heated floors)

  • Proper subfloor preparation and drying

  • Temperature within limits

  • Experienced installer familiar with UFH

New Build Considerations

New builds with UFH present specific challenges.

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Common issues we see:

  • Rush to complete before screed properly dried

  • UFH not commissioned before flooring scheduled

  • Developer pressure to install before appropriate

  • Very dry indoor environment in first winter (new heating, well-insulated)

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Our approach in new builds:

  1. Insist on minimum 6-8 week screed cure time

  2. UFH must be fully commissioned before we install

  3. Moisture testing mandatory, no exceptions

  4. Extended acclimatisation period (2-3 weeks minimum)

  5. Clear expectation-setting with client about movement

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Advice for new build buyers:

  • Don't rush flooring installation

  • Better to wait and do it right

  • First year will show most movement (new heating, building settling)

  • Normal movement is expected and acceptable

Retrofit UFH Considerations

Adding UFH to existing properties has different challenges.

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Low-profile UFH systems:

  • Minimal floor height increase (15-20mm)

  • Electric or water-based options

  • Work well with engineered floors

  • Allow UFH in properties where full screed impossible

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Over existing wooden subfloors:

  • UFH plates/panels between joists

  • Insulation below essential

  • Works with both solid and engineered flooring

  • Professional design critical for effective heat distribution

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Floor height increase:

  • UFH adds height (affects doors, stairs, transitions)

  • Plan for door trimming, threshold adjustments

  • May affect room proportions slightly

Our Recommendations Summary

For new builds or major renovations with UFH:

  • Choose 15mm engineered oak with at least 4mm wear layer

  • Fully glued installation

  • Herringbone pattern distributes movement beautifully

  • Oil or matte lacquer finish

  • Insist on proper UFH commissioning before installation

  • Budget adequate time for screed drying

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For retrofit UFH in existing properties:

  • Engineered oak over low-profile systems

  • Consider narrower planks for visual stability

  • Account for floor height increase

  • Professional UFH design essential

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For solid oak enthusiasts with UFH:

  • Maximum 18mm thickness

  • Maximum 120mm width (narrower is safer)

  • Herringbone pattern ideal

  • Realistic expectations about seasonal gaps (2-3mm acceptable)

  • Excellent humidity control essential

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For maximum stability and minimum worry:

  • Engineered oak, no question

  • 90-120mm plank width

  • Fully glued installation

  • Maintain 45-55% RH year-round

  • 23-25°C surface temperature maximum

Final Thoughts

Wood flooring and underfloor heating absolutely can work together - we've installed many of successful combinations.

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The keys to success:

  1. Choose engineered oak for best performance

  2. Ensure UFH is properly commissioned before installation

  3. Respect temperature limits (maximum 27°C surface)

  4. Maintain stable humidity year-round

  5. Operate UFH sensibly (gradual changes, never fully off)

  6. Accept that some seasonal movement is normal

  7. Work with experienced installers who understand both wood and UFH

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The payoff:

  • Beautiful wood floors

  • Comfortable, even heating

  • No radiators taking up wall space

  • Energy-efficient heating

  • Increased property value

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We install more floors over UFH every year as the technology becomes standard in new builds and renovations. When done correctly, it's an excellent combination that clients love.

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The occasional 1-2mm winter gap is a small price to pay for the aesthetic and comfort benefits. With realistic expectations and proper installation, you'll love your heated wood floor.

Questions About Your Project?

Planning a wood floor with underfloor heating? Call us on 07856 308 208 or email contact@crafthardwood.co.uk

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We serve Chorley, Lancashire, Greater Manchester, Liverpool, and throughout the North West. We have extensive experience with UFH installations and will ensure your floor is specified and installed correctly for long-term performance.

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