Project Overview
A homeowner in Fulham, SW6, needed a full boiler and flue replacement at a high-end residential property, with the flue running through the ceiling of a rear extension. The project combined a technically demanding flue removal and reinstallation with a new Worcester Bosch Greenstar boiler, followed by a full ceiling reinstatement and redecoration to bring the finished space back to a high standard.
The work was carried out by our engineers Darren and Nick, with our reinstatement team following on to complete the boxing in and decoration, delivering a fully commissioned, Gas Safe registered system and a ceiling finished to match the rest of the property.

The Client’s Brief
The property’s existing flue ran through the ceiling of a rear extension and needed full replacement alongside the boiler itself. The client needed:
- A full boiler and flue replacement carried out to a high standard, appropriate for a high-end property
- Careful, controlled ceiling access rather than unnecessary disruption to the wider space
- The new flue connected correctly into an existing roof collar installed earlier in the year
- A complete, uniform redecoration of the affected ceiling once works were finished, so no visible sign of the works remained
Our Survey & Recommendations
The existing flue installation, approximately three metres including elbows, ran through the ceiling of the rear extension and needed to be fully removed as part of the works. Our approach was to gain careful access by removing sections of the existing coving and forming a controlled access channel within the ceiling, rather than opening up the space more than necessary.
The new flue needed to connect into an existing roof collar that had been installed in January, so the replacement flue run was planned to tie into that collar correctly while meeting current manufacturer specifications and regulations.
The Work We Carried Out
Ceiling access and flue removal
- Carefully gained access to the rear extension ceiling by removing sections of existing coving
- Formed a controlled access channel within the ceiling to expose the existing flue system
- Removed the existing flue installation, approximately three metres, including the vertical flue section and associated 45-degree elbows penetrating the flat roof
Flue and boiler installation
- Supplied and installed a new Worcester Bosch flue system, approximately three metres in total run
- Installed a new horizontal and vertical flue configuration, including 45-degree elbows as required
- Connected the new flue system into the existing roof collar installed in January, in full compliance with manufacturer specifications and current regulations
- Supplied and installed a Worcester Bosch Greenstar 30Ri Compact heat-only boiler
- Adapted and connected to the existing gas supply, condensate pipework, and heating system
- Connected to all existing hydraulic and external system components
System protection and water treatment
- Supplied and installed a 28mm magnetic system filter
- Carried out a full system powerflush in accordance with BS 7593
- Carried out system water treatment and inhibitor dosing on completion
System checks and optimisation
- Tested the existing gas supply for tightness and compliance
- Inspected all radiators and valves for adequate heat output and condition
- Balanced the system to ensure optimal performance and efficiency
Ceiling reinstatement and making good
- Reinstated plasterboard to all opened ceiling areas
- Supplied and installed three fire-rated access panels at agreed intervals
- Skimmed plaster to affected areas to a smooth finish
- Prepared and repainted the entire affected ceiling area to ensure a uniform appearance following water damage and the works carried out
Commissioning and handover
- Fully commissioned the new boiler and system in accordance with manufacturer guidelines
- Completed Benchmark certification and all required documentation
- Notified Local Authority Building Control and registered the installation with Gas Safe
- Demonstrated operation of the system and controls to the client
A formal written testimonial was not obtained for this project. The works were completed to the agreed scope, with the system fully commissioned and the ceiling reinstated to a high standard throughout.
Timeline & Completion
The project was carried out by our engineers Darren and Nick, with our reinstatement team following on to complete the boxing in and decoration once the boiler and flue works were finished. The system was fully commissioned, certified, Gas Safe registered, and handed over to the client.
Challenges & How We Solved Them
A flue run through an extension ceiling
With the flue running through the ceiling of a rear extension, access had to be carefully controlled rather than simply opening up the space. Removing sections of existing coving and forming a defined access channel let us reach and remove the old flue, approximately three metres including elbows and its flat-roof penetration, without unnecessary disruption to the rest of the ceiling.
Connecting into an existing roof collar
The new flue needed to tie into a roof collar that had been installed separately in January. Planning the new horizontal and vertical flue configuration, including the required 45-degree elbows, around that existing collar meant the installation met manufacturer specification and current regulations without needing further roof works.
Making good to a high standard
Given the quality of the property, the ceiling reinstatement needed to match the existing finish closely, not just be functionally sound. Plasterboard was reinstated throughout the opened area, three fire-rated access panels were fitted for future servicing, and the affected ceiling was skimmed and fully repainted to remove any visible trace of the works or the water damage that preceded them.
The Finished Result
The property now has a fully commissioned Worcester Bosch Greenstar 30Ri Compact boiler with a correctly installed flue run, tied cleanly into the existing roof collar. The system has been powerflushed, protected with a magnetic filter, and dosed with inhibitor, and all radiators have been checked and balanced. The ceiling has been fully reinstated, skimmed, and redecorated, with three fire-rated access panels providing future servicing access without further disruption. All Gas Safe registration and Building Control notification requirements have been completed.
Project Investment
Pricing for a project of this kind depends on the flue configuration, the extent of ceiling access required, and the finish specified for the reinstatement and decoration work. Contact us for a tailored quotation.
Why Choose Plumb London
- Over 35 years of trading history as a family-run London business
- Gas Safe registered engineers, with full Benchmark and Building Control documentation as standard
- In-house capability across boiler installation, flue work, and ceiling reinstatement and decoration, no need to coordinate separate contractors
- Careful, controlled access methods appropriate for high-end properties
- Full system protection as standard: magnetic filtration, powerflushing, and inhibitor dosing
Frequently Asked Questions
Why does a flue running through a ceiling need to be fully replaced rather than repaired?
Where a flue has deteriorated or needs to be reconfigured to suit a new boiler, a full replacement of the affected run ensures the whole system meets current manufacturer specification and regulations, rather than mixing old and new sections. It also allows any water damage caused by the original fault to be properly addressed at the same time.
What is a fire-rated access panel and why is it fitted?
A fire-rated access panel is a flush-fitting panel that allows future access to a flue or pipework run without needing to cut into the ceiling again, while maintaining the fire resistance of the ceiling itself. Fitting these during reinstatement significantly reduces the cost and disruption of any future servicing.
Can the ceiling be made good to match the rest of the room?
Yes. Our approach is to reinstate plasterboard, skim the affected area to a smooth finish, and fully repaint rather than just patch the immediate area, so the ceiling reads as a single, uniform finish rather than a visible repair.
What does a full system powerflush involve?
A powerflush, carried out in accordance with BS 7593, removes sludge, scale, and debris from the central heating system using specialist equipment and chemicals, protecting the new boiler and helping maintain its manufacturer warranty.








