The Story
The Unifloor Heat-Pak® Dual Board Overlay System is a fast-track, pre-fabricated subfloor solution engineered specifically for installation directly over all types of underfloor heating — including electric cable, mat, foil and film systems as well as hot-water (hydronic) UFH. Comprising a 3 mm MDF baseboard bonded to a 4 mm MDF top board with a factory-applied interactive contact adhesive, each pair of boards clicks together in a staggered overlap joint to produce a seamless, ghost-free surface for direct glue-down of LVT, vinyl sheet, linoleum, rubber, cork and carpet. At just 7 mm total thickness and with an ultra-low TOG rating of 0.7, Heat-Pak® keeps your heat energy flowing freely upward — with no smoothing compound, no drying time and no wet trades required.
(3 mm base + 4 mm top)
Ultra-Low Rating
±1.5 mm tolerance
Dry-Fit System
FSC Certified
Heat-Pak® is an entirely dry installation system. Unlike smoothing compounds or self-levelling screeds, there is no curing or setting time. Your chosen floor covering can be glued down immediately after the boards are laid, reducing project time significantly on both domestic and commercial jobs.
The twin-layer overlap joint configuration staggers the board edges so that no joint lines telegraph through high-sheen finishes such as polished LVT or sheet vinyl. This is a critical advantage over single-board underlays and traditional ply overlays where joint lines commonly reflect through gloss floor surfaces.
For electric cable, mat, foil or film underfloor heating systems, Unifloor recommends laying Heat-Blok® (6 mm, TOG 1.9) as a thermal insulation layer directly beneath the heating element. Heat-Pak® is then installed above the element (TOG 0.7 above, TOG 1.9 below), ensuring heat is directed upward rather than lost into the subfloor. This combination also achieves up to 21 dB ΔLw impact sound reduction with glued linoleum, per EN-ISO 10140-3:2010.
When Heat-Pak® is used over a floor cooling system (rather than floor heating), a moisture monitoring system is required beneath the boards to prevent condensation damage. Consult your UFH supplier for appropriate moisture management products before installation.
Why Heat-Pak® outperforms traditional subfloor methods:
An MDF core has inherently low thermal mass compared to cement-based levelling compounds. At TOG 0.7, Heat-Pak® allows heat energy to pass through rapidly, giving you a fast warm-up time and no energy wastage trapped below the floor surface. Conventional smoothing compounds can have significantly higher thermal resistance, throttling UFH output.
Both the 3 mm baseboard and 4 mm topboard arrive from the factory already coated with a special interactive contact adhesive. Simply press the two layers together under the weight of installation and the adhesive creates a strong, permanent, full-surface bond. No additional glue or bonding agent is required between the two MDF layers — reducing materials cost and on-site consumables.
Heat-Pak® is confirmed compatible with electric cable systems, electric mat systems, electric foil and film systems, and hot-water (hydronic) underfloor heating. The boards are simply placed over the heating element — the low-profile 7 mm build-up means minimal floor level change at door thresholds and room transitions compared to screeded systems.
Once laid, the MDF panel stack encapsulates and mechanically protects the entire heating element from foot traffic, tool drops and compressive loads during flooring installation above. At the same time, the smooth, dimensionally stable surface ensures your LVT, vinyl, linoleum or carpet adheres evenly — with no undulations, ridges or hot-spot cracking in the finish.
The dual-board offset layout means baseboard joints and topboard joints never align in the same location. This staggered configuration distributes structural load evenly and prevents joint-line reflection (ghosting) through high-gloss or thin resilient floor coverings — a common complaint with single-layer plywood or OSB overlays and with hardboard pinned directly to joists.
Because Heat-Pak® is a completely dry, pre-fabricated system, there is no compound mixing, no waiting for leveller to cure and no risk of contaminating the heating element with wet chemistry. The boards are quick to cut with standard hand or power tools, and the finished floor covering can follow in the same working day — a significant commercial advantage over traditional floor-prep methods.
| Heat-Pak® Technical Specifications | |
|---|---|
| Product Code | UNIHEAT-PAK |
| Total Thickness | 7 mm (±0.2 mm) |
| Board Composition | 3 mm MDF baseboard + 4 mm MDF topboard |
| Board Dimensions | 600 mm × 1200 mm (±1.5 mm tolerance) |
| Coverage per Pack | 2.88 m² |
| Thermal Resistance (TOG) | 0.7 |
| Adhesive System | Factory-applied interactive contact adhesive (both boards) |
| Joint Configuration | Staggered overlap — prevents ghosting through finish floor |
| Core Material | High-quality MDF (Medium Density Fibreboard) |
| Compatible UFH Types | Electric cable, mat, foil & film systems; hot-water (hydronic) UFH |
| Suitable Floor Coverings | LVT, vinyl sheet, linoleum, rubber, cork, carpet (glue-down) |
| System Type | Free-floating, dry installation — no setting time |
| Impact Sound Reduction | Up to 21 dB ΔLw (with Heat-Blok® + glued linoleum, per EN-ISO 10140-3:2010)* |
| Certification | NSG Certified; FSC Certified (FSC C154437) |
| Manufacturer | Unifloor B.V., Deventer, Netherlands (UK) |
* Impact sound reduction measured on a standard concrete floor under laboratory conditions. Results on timber substrates will differ.
🔧 Installation Overview
Heat-Pak® is designed for rapid, tool-light installation by professional flooring contractors and competent self-installers:
- Install your underfloor heating system in the normal manner and test per manufacturer instructions.
- Lay the 3 mm MDF baseboards directly over the heating element, staggering joints from the topboard layer.
- Press the 4 mm MDF topboards onto the baseboards — the factory-applied contact adhesive bonds instantly on full-surface contact.
- Cut boards to size at room perimeters using a standard hand saw, jigsaw or circular saw.
- Glue down your chosen resilient floor covering immediately — no waiting time required.
● For electric UFH: lay Heat-Blok® insulation beneath the element before installing Heat-Pak® above it for optimum efficiency and sound reduction.
Frequently Asked Questions
Details & Craftsmanship
Every detail has been carefully considered to bring you the perfect product.
Details & Craftsmanship
Every detail has been carefully considered to bring you the perfect product.
Description
The Unifloor Heat-Pak® Dual Board Overlay System is a fast-track, pre-fabricated subfloor solution engineered specifically for installation directly over all types of underfloor heating — including electric cable, mat, foil and film systems as well as hot-water (hydronic) UFH. Comprising a 3 mm MDF baseboard bonded to a 4 mm MDF top board with a factory-applied interactive contact adhesive, each pair of boards clicks together in a staggered overlap joint to produce a seamless, ghost-free surface for direct glue-down of LVT, vinyl sheet, linoleum, rubber, cork and carpet. At just 7 mm total thickness and with an ultra-low TOG rating of 0.7, Heat-Pak® keeps your heat energy flowing freely upward — with no smoothing compound, no drying time and no wet trades required.
(3 mm base + 4 mm top)
Ultra-Low Rating
±1.5 mm tolerance
Dry-Fit System
FSC Certified
Heat-Pak® is an entirely dry installation system. Unlike smoothing compounds or self-levelling screeds, there is no curing or setting time. Your chosen floor covering can be glued down immediately after the boards are laid, reducing project time significantly on both domestic and commercial jobs.
The twin-layer overlap joint configuration staggers the board edges so that no joint lines telegraph through high-sheen finishes such as polished LVT or sheet vinyl. This is a critical advantage over single-board underlays and traditional ply overlays where joint lines commonly reflect through gloss floor surfaces.
For electric cable, mat, foil or film underfloor heating systems, Unifloor recommends laying Heat-Blok® (6 mm, TOG 1.9) as a thermal insulation layer directly beneath the heating element. Heat-Pak® is then installed above the element (TOG 0.7 above, TOG 1.9 below), ensuring heat is directed upward rather than lost into the subfloor. This combination also achieves up to 21 dB ΔLw impact sound reduction with glued linoleum, per EN-ISO 10140-3:2010.
When Heat-Pak® is used over a floor cooling system (rather than floor heating), a moisture monitoring system is required beneath the boards to prevent condensation damage. Consult your UFH supplier for appropriate moisture management products before installation.
Why Heat-Pak® outperforms traditional subfloor methods:
An MDF core has inherently low thermal mass compared to cement-based levelling compounds. At TOG 0.7, Heat-Pak® allows heat energy to pass through rapidly, giving you a fast warm-up time and no energy wastage trapped below the floor surface. Conventional smoothing compounds can have significantly higher thermal resistance, throttling UFH output.
Both the 3 mm baseboard and 4 mm topboard arrive from the factory already coated with a special interactive contact adhesive. Simply press the two layers together under the weight of installation and the adhesive creates a strong, permanent, full-surface bond. No additional glue or bonding agent is required between the two MDF layers — reducing materials cost and on-site consumables.
Heat-Pak® is confirmed compatible with electric cable systems, electric mat systems, electric foil and film systems, and hot-water (hydronic) underfloor heating. The boards are simply placed over the heating element — the low-profile 7 mm build-up means minimal floor level change at door thresholds and room transitions compared to screeded systems.
Once laid, the MDF panel stack encapsulates and mechanically protects the entire heating element from foot traffic, tool drops and compressive loads during flooring installation above. At the same time, the smooth, dimensionally stable surface ensures your LVT, vinyl, linoleum or carpet adheres evenly — with no undulations, ridges or hot-spot cracking in the finish.
The dual-board offset layout means baseboard joints and topboard joints never align in the same location. This staggered configuration distributes structural load evenly and prevents joint-line reflection (ghosting) through high-gloss or thin resilient floor coverings — a common complaint with single-layer plywood or OSB overlays and with hardboard pinned directly to joists.
Because Heat-Pak® is a completely dry, pre-fabricated system, there is no compound mixing, no waiting for leveller to cure and no risk of contaminating the heating element with wet chemistry. The boards are quick to cut with standard hand or power tools, and the finished floor covering can follow in the same working day — a significant commercial advantage over traditional floor-prep methods.
| Heat-Pak® Technical Specifications | |
|---|---|
| Product Code | UNIHEAT-PAK |
| Total Thickness | 7 mm (±0.2 mm) |
| Board Composition | 3 mm MDF baseboard + 4 mm MDF topboard |
| Board Dimensions | 600 mm × 1200 mm (±1.5 mm tolerance) |
| Coverage per Pack | 2.88 m² |
| Thermal Resistance (TOG) | 0.7 |
| Adhesive System | Factory-applied interactive contact adhesive (both boards) |
| Joint Configuration | Staggered overlap — prevents ghosting through finish floor |
| Core Material | High-quality MDF (Medium Density Fibreboard) |
| Compatible UFH Types | Electric cable, mat, foil & film systems; hot-water (hydronic) UFH |
| Suitable Floor Coverings | LVT, vinyl sheet, linoleum, rubber, cork, carpet (glue-down) |
| System Type | Free-floating, dry installation — no setting time |
| Impact Sound Reduction | Up to 21 dB ΔLw (with Heat-Blok® + glued linoleum, per EN-ISO 10140-3:2010)* |
| Certification | NSG Certified; FSC Certified (FSC C154437) |
| Manufacturer | Unifloor B.V., Deventer, Netherlands (UK) |
* Impact sound reduction measured on a standard concrete floor under laboratory conditions. Results on timber substrates will differ.
🔧 Installation Overview
Heat-Pak® is designed for rapid, tool-light installation by professional flooring contractors and competent self-installers:
- Install your underfloor heating system in the normal manner and test per manufacturer instructions.
- Lay the 3 mm MDF baseboards directly over the heating element, staggering joints from the topboard layer.
- Press the 4 mm MDF topboards onto the baseboards — the factory-applied contact adhesive bonds instantly on full-surface contact.
- Cut boards to size at room perimeters using a standard hand saw, jigsaw or circular saw.
- Glue down your chosen resilient floor covering immediately — no waiting time required.
● For electric UFH: lay Heat-Blok® insulation beneath the element before installing Heat-Pak® above it for optimum efficiency and sound reduction.
Frequently Asked Questions
