Removal of BISF house cast iron flue pipe & fireplace by site member Doug.
(Admin note: Non Standard House member Doug has kindly put together the following excellent post, depicting the complete process of a the flue removal from the inside of a typical BISF house. By creating this post, and taking the time to record the entire process, Doug hopes that he can share his experience with other members, and more importantly, he hopes that it may be a useful resource for all. Our sincere thanks to Doug for this valuable contribution)
I recently removed the cast iron flue and fireplace from a BISF house and thought that I would share it with you all. This post relates to BISF Houses where the fireplace is fitted to wall between the living & dining rooms.
Before starting there are few safety points to bear in mind.
- You will need a 6-12 inch cast chain cutter. This is a heavy item and will require 2 persons to complete the job.
- Always wear safety glasses and gloves and if possible, steel toecap shoes just in case.
- Always wear a high quality dust mask and wherever possible always dampen down any insulation material that may surround the flue with a spray bottle of water. Although not prescribed, we can never rule out the possibility that installers may have used asbestos insulation in some cases. If you suspect the presence of asbestos do not undertake this work until the material has been correctly tested by an approved body.
- Always wear a disposable work overall with hood as this can be an extremely dusty job.
- Never use an angle grinder as sparks can easily ignite insulation or travel under floorboards, causing fire.
- A strong working platform and extra lighting in the roof would also be a good idea.
- Don’t remove any of the supporting frames yet as it contains the pipe clamps which keeps the flue pipe in place. You can work around the frame without any problem.E
- Ensure that any and all pipework leading into or out of the fireplace are disconnected or safely capped off away from the work area.
- All gas pipes should be disconnected by a Corgi registered engineer.
- Any electrical connections should be removed by a qualified electrician.
- Water pipes if present should also be removed and capped if of no further use.
- Always turn the gas off at the mains prior to undertaking any work as there may be hidden gas pipes that you are not aware of.
Originally, BISF houses were fitted with open coal fires that heated a small sealed back boiler that was situated behind the main firebox. This was a basic water or oil filled unit that heated radiators in the house. If still present, the box and pipework should be capped and carefully removed.
Admin Update: There have been a number of safety incidents including one fatality where old solid fuel back boilers have exploded due to the re-commisioning of old coal fires. Such events are not specific to BISF Houses. Please see http://www.hse.gov.uk/services/localgovernment/boilers.htm
In the 1980’s many BISF properties were fitted with Baxi Bermuda gas fires with integrated back boilers. The back boiler was positioned inside the firebox, directly behind the fire itself.
This fire is fairly straightforward to remove once the gas feed has been safely disconnected. The front of the gas fire can pulled forward and safely disconnected.
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This first step assumes that all gas and electrical connections have already been removed by qualified tradesmen.
Some BISF houses were fitted with original coal fire powered back boilers. If still present, these will also need to be disconnected and removed.
The same goes for owners of Baxi Bermuda gas fires with rear gas fired back boilers.
Please ensure that normal safety procedures are always followed.
Do not start working on any fireplace, back-boiler, or flue, until you are 100% certain it has been fully and safely disconnected.
The information posted here, is for entertainment purposes only and should not be viewed as a definitive guide in any shape or form. We take no responsibility for any loss or damage caused as a direct result of anyone replicating the information posted here. Do so at your own risk. You have been warned.
First, I completely remove the existing fireplace surround. The surround is usually constructed from large slabs which should be pretty easy to break up using a lump hammer or similar.
I thought It would be wise to dismantle the top mantle slab first. Once stripped away I should be left with the concrete firebox surround and steel frame
Because I actually planned on removing the middle section of the flue that runs up through the bedroom, I also had to remove the hardboard boxing that surrounded the metal flue encasement, from the bedroom.
Some people choose to only remove the section of pipework that is visible in the living room, but if this is done, I am aware that it must be braced and supported to prevent the rest of the pipe from sliding down and causing injury.
A closer look at the first floor joint connection of the flue pipe.
If the lower section is removed, and the upper section left in place, then it must be braced in some way using metal supports bolted to the framework.
Starting in the attic this image shows the cast iron flue ‘tube’ passing through the fixed ceiling/frame support plate as it starts its journey down through the house, via the openings the loft and ground floor ceiling.
This image shows the point where the cast iron flue exits the building through the roof. The grey material is a moisture membrane, that was installed when the original roof covering was replaced.
You can also see that the flue is clamped into place, along with the steel flue support structure, which should always be left in-situ, as it is connected to the roofs framework.
As I won’t be disturbing the upper loft top portion of the flue, my first cut will be just under the top clamp. The chain cutter is fed around the tube and locked into position, then slid upward to the first cut point.
The cutter works on a ratchet system which slowly tightens the chain until it cracks the tube, it’s quite noisy and a bit scary. Also worth noting, in my case, there was a flue liner fitted inside the pipe. This is because there used to be a gas fire fitted with a rear gas powered back boiler that once fitted snugly in the old fireplace. The Flue will need to be removed before I can move forward. This is why I made 2 cuts in the flue pipe. The pipe is quite heavy as it’s constructed from cast iron, and therefore easier to manage when cut into manageable pieces.
I managed to position a reciprocating saw through a small gap between the cuts, and was able to cut through the flue liner.
I then removed the middle flue section before going downstairs to pull the liner out of the pipe.
I removed the flue liner by pulling it in a downward and outward motion until the liner came free from the flue, along with a large amount of soot, dust and rust etc. PLEASE BE WARNED THIS IS A VERY DIRTY PART OF THE JOB – DUST SHEETS ARE HIGHLY RECOMMENDED.
*CAUTION* if you cut off a flue section which is unsupported, the top cut section jumps upwards due to the force of the cut, BE PREPARED FOR THIS. it is very heavy.
My next cut was in the bedroom, tight to the ceiling, then another cut half way above floor level, then another at floor level.
You could cut larger sections but I opted to cut small sections for safety and handling purposes.
Mid section Cut, allowing for the upper section to be easily maneuvered out of the cage.
This job would be best suited to two persons, but at the time, I was working alone.
Cutting the lower section.
By the way, the cutting tool can be hired from most good hire shops or purchased online.
One more cut in the lounge, a third of the way up from the ceiling.
I removed the cut section from above in the bedroom.
The final section was still sitting inside the coupling plate on top of the fire box, but it was east to wriggled about until it became loose enough to tilt back and lift out.
It’s worth noting that there is also a support plate/box located at floor joist level in between the ground and first floor.
Back to Bedroom
This is a view of the flue cage, after the flue pipe and the majority of the fireplace slabs have been removed.
You are now left with the frame which is bolted together in 4 sections then another 4 sections in the bedroom bolted to the downstairs frame.
A closer view of the flue pipe collar connection to the fireplace.
There are wooden batons nailed in the corner angles to which the plasterboard was nailed to.
The nails can be pulled out using a claw hammer, in order to remove the baton and enable to access the frame bolts. This is a straight forward but a fiddly job.
The bottom of the frame is cast into the concrete plinth. I cut the frame at floor level to enable me to remove it as I won’t be taking up the concrete plinth just yet. Once all the frame has been removed the concrete fire box can be removed in sections and although a little heavy, it is easily removed.
The frame can be unbolted in parts and cut in other. It is quite straightforward once the flue is out of the way. Unfortunately I did not take any photographs of that part.
The next job is to make good the ceilings and floors but as I’m about to undertake a major refurbishment of the lounge, the making good will be part of that project and completed in due course.
My local scrap merchant took all the scrap away at no cost to me and he even loaded it himself!
I hope my little project was helpful. If anyone has any questions or comments, just ask away.
All Project Gallery Images
We have also included several other members flue removal images below, which may help those wishing to undertake a similar project.