PHAM NEWS | DECEMBER/JANUARY 2026 Underfloor Heating 39


Get in the groove with low profile panels


Amber Underfloor Heating’s technical manager, Steven Burnett, explores the benefits of grooved overlay underfloor heating – and provides some expert tips for installers.


system – involves installing grooved panels, typically EPS insulation with a foil covering, on top of an existing subfloor. The grooves in the panels


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create channels for underfloor heating pipes to sit in, allowing the water to flow through the pipes, warm the floor covering above, and heat a room evenly.


The key benefits So what are some of the main benefits of installing a grooved overlay underfloor heating system?


Easy to retrofit on existing


floors: The grooved overlay system is sometimes known as a retrofit system because it’s simple to install over existing floors, which is a common occurrence in a renovation project. While traditional systems


may require excavation to the existing floor, a grooved overlay can be installed onto an existing subfloor without causing major disruption. We offer two different grooved overlay solutions; a 16mm panel that holds 12mm pipe at 120mm pipe centres and a 20mm panel that holds 16mm pipe at 150mm pipe centres.


Fast installation: The pre- formed grooves make pipe placement simple for easy installation. Plus, due to the minimal


preparation or floor build- up required – just spray the prepared sub-floor and lay the board – grooved overlay panels are quicker to install than other systems.


Ideal for renovations and upper floors: As previously mentioned, because they can be installed on top of an existing floor, grooved overlay systems are ideal for renovations as they require little additional work.


Steven Burnett Technical manager for Amber Underfloor Heating


grooved overlay underfloor heating system – sometimes known as a low profile or retrofit


Also, as they need minimal floor build-up (typically 16 or 20mm), they have little impact on floor height, so they’re a fantastic option for upstairs rooms where ceiling height is at a premium.


Energy efficiency: Underfloor


heating is an excellent distributor of heat, allowing lower water temperatures than radiators, as the whole floor surface is a heat emitter. This means that underfloor heating systems are an excellent choice for a heat pump setup. Even heat distribution: Grooved overlay systems offer even heat distribution. Featuring pre-formed and ideally-spaced channels for the underfloor heating pipes to be placed into, the foil covering enables the panels to evenly distribute heat across a floor, reducing cold or hot spots.


Compatible with many floor finishes: Grooved overlay systems can be used with most floor finishes. Tiles can typically be fixed to the boards directly using approved adhesive and primer. Laminate and engineered wood can typically be laid directly on top. If using carpet or vinyl, a layer of renovation screed should be applied prior to installing the floor covering. Most other floor finishes can be installed onto any of our


Main considerations What do you need to consider when installing a grooved overlay system?


Subfloor preparation: Prior to the installation of grooved overlay panels, the subfloor should be suitably prepared – free of debris, levelled and stable. This is because the pipework must be installed at a consistent depth below the floor finish to ensure there are no hot or cold patches. Layout planning: Planning your layout is key! The location of the manifold is very important, and we would always recommend this is kept as centrally as possible to minimise the amount of flow and return pipework required going from the manifold to each room.


Panel installation: Installing the panels is simple – just spray the prepared subfloor with spray adhesive to bond the boards according to your floor layout! Ensure you plan the pipe layout prior to installing the panels. Plus, you may need to cut the boards to fit the space,


panels with a layer of renovation screed, but we recommend consulting the user guide. It is always recommended to consult the flooring manufacturer’s guidelines prior to installing the flooring.


which is easy to do with a fine- toothed saw or craft knife. Pipe laying: Pipes should be laid within the pre-formed grooves. They should be placed fully and firmly inside the grooves to minimise the chance of hot or cold spots. Floor finishes: While most floor finishes are compatible with grooved overlay panels, you must consider the effect your chosen finish has on the floor height when used in combination with an overlay system, due to possible extra preparation work and build-up being required. Heat output: Just like all


heating installations, you should consider the output of the system to ensure it meets your requirements. The output is mainly affected by your chosen finish and water temperature of your heat source.


General best practices: We always recommend installers follow industry best practices. This includes thorough preparation, carefully following your planned layout – and abiding by manufacturers’ guidelines.


Help at hand


Our design team and technical team are on hand to assist with any installation queries you may have. ◼ phamnews.co.uk/126/47


Minimal disruption for church heating upgrade


A recently completed project installing underfloor heating from Ultra-Fin has demonstrated how a Grade I listed building can be upgraded for better energy efficiency without disturbing its historic internal fabric, while also allowing for a future transition to a fully renewable heating system. Ultra-Fin supplied and installed


the system at St Paul’s Church in Covent Garden, addressing both comfort and long-term adaptability. Designed for joisted floors, it allowed the existing boards to be lifted and replaced with minimal disruption. The project involved detailed


planning to calculate how the joists would be notched and to specify the insulation required to limit heat loss. A 50mm layer of non-combustible insulation was laid beneath the pipework,


Recycled aluminium offers a more sustainable solution


Faster heat, lower energy use, and a smaller carbon footprint are said to be the main benefits of the new DEVIcell Low Carbon insulation plate system. The system is made from 75% recycled aluminium and provides up to 33% faster heat-up times. It is suitable for dry installations beneath wood, laminate or parquet floors, as well as wet screed installations beneath tiles, making it compatible with a wide range of floor surfaces. The DEVIcell Low Carbon uses a full aluminium covering with ready-


supported by a breathable barrier membrane stapled over the joists and darkened along its top edge to prevent it showing between the boards. Installation of the composite


pipework and Ultra-Fin diffusers took 13 days, after which engineers connected the system to the existing boiler and commissioned it. The heating now covers the


nave across 10 bays, divided into 12 zones, with spare manifold ports allowing a future switch to renewable heat sources. Sensors were added to keep


the timber floors within a safe temperature range and early use suggests the nave warms more quickly than under the previous radiator layout. ◼ phamnews.co.uk/126/48


made grooves for installing DEVIflex 6T and 10T heating cables. This construction supports faster reaction times, even heat distribution, and consistent floor temperatures. By reflecting heat back into the room and reducing heat loss, the system is designed to lower energy consumption while maintaining performance. The plates are easy to


handle and can be fitted in both dry and wet systems, offering flexible installation for renovations or new builds. ◼ phamnews.co.uk/126/49


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