At DDL Plumbing & Heating, we believe the quality of an underfloor heating installation is determined just as much by the preparation and attention to detail beneath the finished floor as it is by the components you eventually see.
This recent project involved the installation of a water-based (wet) underfloor heating system, using a pre-routed underfloor heating overlay board system, taking the floor from its initial preparation through to the installation of the UFH pipework, manifolds and controls, ready for the next stage of the floor construction.
While the finished result will eventually be hidden beneath the floor, there is a considerable amount of work involved in creating a reliable and efficient underfloor heating system.
Here is how we completed the installation.
Stage 1 – Preparing and Cleaning the Existing Floor
Before any underfloor heating components were installed, the existing floor needed to be properly prepared.
The entire floor area was thoroughly swept and cleaned to remove dust, plaster, loose material and general building debris.
It may sound like a relatively simple part of the installation, but preparing the substrate correctly is extremely important.
Any debris trapped underneath the UFH overlay boards can prevent them from sitting completely flat against the substrate. Even relatively small pieces of material can create raised areas or unwanted movement in the boards.
A clean and level substrate therefore gives us a stable base from which to install the remainder of the system and helps ensure that the overlay boards remain properly supported across the floor.
We also inspect the area for significant high spots, low spots or other irregularities before proceeding.
Good underfloor heating starts with good preparation.
Stage 2 – Setting Out the Underfloor Heating Overlay Boards
Once the substrate had been prepared, we began installing the pre-routed underfloor heating overlay boards.
The overlay boards contain accurately formed pipe channels or grooves, which determine the route of the underfloor heating pipework across the floor.
The boards cannot simply be placed down randomly.
Each UFH overlay board needs to be carefully positioned and aligned with the neighbouring boards so that the pipe channels meet correctly and create a continuous route for the heating circuits.
Particular attention is required around walls, doorways, corners and other obstacles.
Correct alignment is important for several reasons.
Firstly, it allows the UFH pipe to follow smooth, controlled routes without unnecessary stress or excessively tight bends.
Secondly, accurate board positioning maintains the designed pipe spacing across the heated floor area. Consistent pipe centres help the system distribute heat evenly through the finished floor rather than creating areas with significantly different pipe spacing.
The layout also needs to take account of how each heating circuit will travel from the underfloor heating manifold, through its designated zone and back to the manifold.
Taking time at this stage makes the pipe installation considerably cleaner and helps produce an organised system that can be commissioned and maintained properly.
Stage 3 – Mechanically Securing the UFH Overlay Boards
After the overlay boards had been correctly positioned and their alignment checked, they were mechanically fixed to the substrate.
The boards were carefully drilled and secured using suitable fixings together with galvanised board fixing washers.
The larger surface area of the washers helps spread the load of the fixing across the overlay board rather than concentrating it at one small point. This provides a secure mechanical fixing while helping to avoid damaging or pulling through the board material.
The galvanised finish also provides additional resistance to corrosion.
This fixing stage is particularly important because the overlay boards must remain securely located and flat against the substrate during the subsequent stages of the floor construction.
When a latex-based self-levelling compound or other compatible floor preparation system is subsequently applied, the boards need to remain securely fixed rather than lifting, floating or shifting out of alignment.
Securely fixing the boards therefore helps maintain the designed pipe layout and provides a stable base for the next stage of the floor build-up.
Stage 4 – Inspecting and Cleaning the Pipe Channels
Before installing any underfloor heating pipe, we carried out another important inspection.
Every pre-routed pipe channel or groove within the overlay boards needed to be checked to ensure that it was clear and free from debris.
Dust, pieces of plaster, board fragments, screws or other building debris must not be allowed to remain inside the channels.
The UFH pipe is designed to sit correctly within these recessed channels. An obstruction underneath it could prevent the pipe from seating fully into the overlay board, potentially leaving a section sitting proud of the surrounding surface.
More importantly, sharp or hard debris trapped underneath or alongside the pipe could create an unwanted point of pressure against the pipe.
We therefore clean and inspect the channels before the pipework is installed rather than relying on the pipe itself to push small obstructions out of the way.
This is another example of a small stage of the installation that can make a significant difference to the quality of the finished system.
Stage 5 – Installing the Underfloor Heating Pipework
With the overlay boards secure and all of the channels inspected, we could begin installing the underfloor heating pipework.
The pipe was carefully fed into the pre-routed channels, following the planned circuit layout for each room and heating zone.
At this stage, care is taken to avoid twisting, kinking or placing unnecessary stress on the pipe.
The bends and return sections are formed smoothly, and the pipe is seated fully within the channels so that it remains securely positioned and does not sit proud of the overlay board.
The photographs from this installation show the importance of a neat and methodical layout. The pipework follows consistent routes across the floor, with controlled bends and clearly defined circuits.
Correct pipe spacing is an important part of UFH design because the floor itself effectively becomes the heat emitter.
Rather than relying on individual radiators positioned around a room, a properly designed underfloor heating system distributes heat across a much larger surface area.
This can create a comfortable and even heat distribution throughout the space while also allowing the system to operate using lower flow temperatures than many conventional radiator systems.
Stage 6 – Routing Each Heating Circuit Back to the Manifold
Each individual pipe loop forms a continuous underfloor heating circuit.
The circuits originate at the manifold, travel through their designated floor area and then return to the manifold.
Where possible, keeping continuous pipe within the floor construction reduces the need for inaccessible joints beneath the finished floor.
At the manifold position, the individual circuits are organised and connected to the appropriate flow and return manifold connections.
The manifold acts as the central distribution point for the underfloor heating system.
Heated water is distributed through the individual circuits before returning through the manifold to the heat source.
The manifold arrangement also allows the individual circuits to be balanced and controlled so that the correct flow can be provided to different areas of the property.
Stage 7 – Labelling Every Underfloor Heating Circuit
An extremely important part of the installation is something that homeowners may never see once the system is finished: every circuit is clearly identified and labelled at the manifold.
Circuits can be labelled according to the room or zone they serve, such as bedrooms, bathrooms, living areas and other individual spaces.
This is important both during commissioning and throughout the future life of the heating system.
When the system is balanced, commissioned, adjusted or maintained, the engineer needs to know exactly which manifold circuit serves which area of the property.
Without clear identification, tracing circuits later can become unnecessarily time-consuming.
Accurate labelling makes commissioning more straightforward and means that future servicing, diagnostics or alterations can be carried out much more efficiently.
It is a relatively small detail, but it is part of leaving behind an organised and professional installation.
Stage 8 – Manifold, Pumps, Actuators and System Control
The manifold assembly is effectively the distribution centre of the wet underfloor heating system.
As well as connecting the individual heating loops, a typical installation can incorporate flow meters, isolation and balancing valves, circulation equipment, thermal actuators and temperature-control components, depending on the system design.
The flow meters allow the individual circuits to be correctly balanced so that each zone receives the required flow rate.
Thermal actuators can open and close individual circuits in response to the relevant room or zone controls, allowing different parts of the property to call for heat independently.
This combination of hydraulic balancing and individual zone control is an important part of creating an underfloor heating system that provides both comfort and efficient operation.
Stage 9 – Testing, Commissioning and Heatmiser Controls
Before the underfloor heating installation is covered by the subsequent floor build-up, the complete system needs to be thoroughly checked and tested.
Once the individual pipe circuits have been connected to the manifold, the system is filled and hydraulically pressure tested in accordance with the system manufacturer’s requirements and the project specification.
Pressure testing is one of the most important quality-control stages of an underfloor heating installation.
The pipework, manifold and accessible connections are inspected while the system is under test pressure to confirm that the heating circuits and connections are sound before the pipework becomes concealed beneath the finished floor construction.
Carrying this out while the system remains exposed means any issue can be identified and rectified before the next stage of the flooring work takes place.
The system pressure is monitored for the required test period, with the pipework and connections checked as part of the process.
Heatmiser Underfloor Heating Controls
This installation will also utilise Heatmiser controls to provide control over the underfloor heating system.
The control system works alongside the manifold and thermal actuators to manage the individual heating zones. Depending on the final system configuration, individual rooms or areas can be controlled according to their heating requirements rather than treating the entire property as one single heating zone.
This provides the homeowner with greater control over when and where heat is required while helping the underfloor heating system operate efficiently.
Combining correctly installed UFH pipework, a properly balanced manifold and Heatmiser underfloor heating controls provides a complete system designed around both comfort and controllability.
Stage 10 – Preparing Latex Levelling Compound and Final Floor Finish
Following successful testing and inspection of the underfloor heating system, the installation can move on to the next stage of the floor build-up.
For this installation, the floor specification includes a 10mm layer of suitable latex-based self-levelling compound over the underfloor heating overlay board and pipework.
The purpose of the levelling compound is to create a smooth and consistent surface over the UFH system. The 10mm latex application encapsulates the pipework and overlay board system, creating a suitable surface ready for the next stage of the floor finish.
The floor preparation and finishing requirements need to take account of the UFH overlay board system, specified 10mm latex application, relevant manufacturer requirements and the final flooring material being installed.
Where this forms part of the wider project requirements, DDL Plumbing & Heating can work alongside the appropriate flooring specialists or help coordinate the next stage of the installation, ensuring the transition from the underfloor heating installation to the finished floor is properly considered.
This allows the requirements of each individual project to determine the most appropriate approach rather than applying a one-size-fits-all solution.
Once the specified floor preparation products have been installed and allowed to cure in accordance with the relevant manufacturer’s requirements, the property can progress towards its chosen finished floor covering.
The completed underfloor heating system will ultimately be almost completely invisible.
But underneath that finished floor is a carefully planned network of heating circuits, securely installed UFH overlay boards, correctly routed pipework and a manifold and control system designed to distribute and regulate heat throughout the property.
Why Installation Quality Matters With Underfloor Heating
A good underfloor heating installation isn’t simply about putting pipe underneath a floor.
It requires careful UFH system design, substrate preparation, accurate overlay board installation, secure mechanical fixing, correct pipe spacing, controlled bend radii, properly organised heating circuits, manifold installation, circuit identification, hydraulic pressure testing, balancing, controls and commissioning.
Getting those details right before the floor is covered is crucial because much of the installation will no longer be accessible afterwards.
At DDL Plumbing & Heating, our approach is to complete each stage methodically, from the preparation of the original floor and installation of the UFH overlay board system through to the pipework, manifolds, controls, testing and commissioning.
The Benefits of Wet Underfloor Heating
When correctly designed and installed, a water-based underfloor heating system can offer a number of advantages:
- Even heat distribution throughout the room
- Reduced reliance on wall-mounted radiators
- More usable wall and living space
- Comfortable radiant heat across the floor area
- Individual room or zone control where specified
- Compatibility with smart heating controls such as Heatmiser
- The potential to operate efficiently at lower flow temperatures
- Compatibility with suitable boilers and heat-pump systems
Underfloor heating can be particularly well suited to modern, well-insulated properties and renovation projects where comfort, efficient heat distribution and a clean interior finish are priorities.
Looking for Underfloor Heating Installation in Kent?
If you’re considering underfloor heating in Kent, DDL Plumbing & Heating can help with the design and installation of a system suited to your property.
We provide complete underfloor heating solutions, including wet underfloor heating, UFH overlay board systems, underfloor heating pipework, manifolds, heating controls, pressure testing and commissioning, with the wider floor build-up considered as part of the overall project requirements.
Whether underfloor heating forms part of a renovation, extension, new heating system or wider property refurbishment, getting the design and installation right from the beginning is essential.
DDL Plumbing & Heating Ltd
3 Joiners Shop, Historic Dockyard, Chatham, Kent ME4 4TZ
01634 944247
office@ddlheating.com
Contact DDL Plumbing & Heating today to discuss your underfloor heating project or request a free, no-obligation quotation.
