Retrofitting underfloor heating into an existing property used to be considered disruptive, costly and impractical, especially in homes with concrete or screed floors. Traditional methods often required either removing the existing floor or adding new build-up layers, leading to increased floor height, weeks of disruption and additional structural work.
Floor milling has changed this completely.
Modern milling technology allows for precise, clean channels to be cut directly into the existing floor, making retrofit underfloor heating not only possible, but fast, efficient and cost-effective.
In this article, we explain what floor milling is, how it works, why it is now widely used in underfloor heating installations, and whether your home may be suitable.
What is floor milling?
Floor milling is a specialised process used to create narrow, accurate channels in existing concrete or screed. These channels are designed to hold water-based underfloor heating pipes without altering the finished floor height.
Using high-precision grinding equipment, experienced teams can cut channels cleanly and with minimal dust. Once the pipework is installed, the channels are sealed and the floor is ready for the final finish.
Why milling is ideal for retrofit underfloor heating
Unlike traditional installation methods, floor milling allows underfloor heating to be integrated into existing homes without major construction work.
Key benefits of milling:
- No floor height increase – pipes sit within the slab, not above it
- Minimal dust and disruption
- No removal of the existing floor structure
- Fast installation (typically 1–2 days)
- Faster heat-up times due to low thermal mass above pipes
- Reduced energy use thanks to more efficient heating response
This makes milling the preferred retrofit solution for homes with concrete floors, extensions and older properties where internal heights cannot be compromised.
How milled underfloor heating works
Here is how the process typically takes place:
- The existing screed or concrete is assessed for suitability.
- Precision milling equipment is used to cut channels following the system design.
- Flexible underfloor heating pipes are laid into the channels.
- The system is pressure-tested to ensure safe operation.
- The channels are sealed and repaired.
- The floor is ready for the final covering (tile, engineered wood, vinyl, etc.).
Unlike other systems, there is no waiting time for screed drying. In most cases, the heating can be commissioned immediately after installation.
How milling improves heating performance
Because the pipes are recessed into the existing slab and positioned closer to the surface, the system provides faster heat transfer and better control. This reduces running costs and enhances comfort.
In fact, installing underfloor heating through milling can improve responsiveness by 20–30% compared to traditional deep-screed systems, making it especially suitable for energy-efficient heating sources such as heat pumps and modern gas boilers.
When milling is the best solution
Floor milling is particularly suitable when:
- A home has solid concrete or screed floors
- The property is being renovated without full floor removal
- Internal floor height cannot be raised
- Radiators are underperforming, especially in large open-plan spaces
- The client wants fast installation without disruption
Common examples include extensions, glass rooms, open-plan kitchens, and older properties where traditional heating is no longer effective.
Is milled underfloor heating right for your project?
Most homes with concrete or screed floors are suitable, provided the existing slab is sound. A professional technical assessment should be completed before installation to determine depths, layout and suitability.
If you’re considering underfloor heating during renovation or converting a cold room into a usable space, milling is one of the most efficient and least invasive options available.
Why choose Channel Heat Systems for precision-milled underfloor heating
Channel Heat Systems specialises in precision-milled underfloor heating installations for both retrofit and new-build projects.
Our team uses advanced milling technology to install systems without height build-up, mess or long downtime. Every system is pressure-tested, connected to the manifold and fully commissioned by experienced engineers.
Installation typically takes just 1–2 days, and the floor is ready for your final finish without expensive structural adjustments.
Get a free underfloor heating assessment
If you’re exploring underfloor heating for your renovation or new-build project, we can help determine whether floor milling is a suitable solution.
Contact us today for professional advice and a free assessment.