boiler flue regulations

Boiler Flue Regulations

Boiler Flue Regulations are key to ensuring your new boiler installation is carried out safely and professionally. If adhered to, these regulations prevent Carbon Monoxide and other toxic gases from escaping out the wrong outlet and putting others in danger. They can be horizontal or vertical, but the position will need to be discussed between you and your installer.

If you’re looking to have a new boiler installed, learning about these boiler flue regulations is essential. Always make sure you’re dealing with an installer that understands them and the importance of following them. Take Boilerhut for example, even if you’re only in the planning stages for a new boiler, you can make things a lot easier by getting a free, no-obligation quote from us. Just enter your details and click the green button below… it’s that easy!

 


Boiler Flue Regulations – What we’re covering

Besides preparation for a new boiler, there are things to consider with Boiler Flue Regulations as well, such as your property’s boundary line. The distance between this line and your boiler flue will need to be at least 60cm, as well as being at least 2.1m off the ground. Knowing these details can really help you when planning your installation, so it’s important to keep this in mind.

Over the course of this article, you’ll get answers to questions such as:

  • What does a boiler flue do?
  • Will I need an engineer?
  • What manufacturer restrictions are there? – If you’re looking for a new boiler, this is particular important. Speak to one our experts on 029 2009 9898 or CLICK HERE to get a free quote online.

Boiler Flue Regulations are put in place for health and safety by protecting us from harmful gases. It’s a testament to the development of modern boiler designs that with the use of the flue and condensate, any dangerous chemicals are safely removed from the system. Read on to find out how boiler flue regulations must be taken into account when planning your new boiler installation… it doesn’t have to be complicated!

 

boiler flue introduction

 


Boiler Flue Regulations – Will I need to replace my old boiler?

If you find that the flue on your old boiler is too low or too close to a neighbouring window, then you may need to make changes to your heating system. It’s not always necessary to get a new boiler at this stage, because some regulations only apply to new installations.

According to the regulations, all boilers across the UK also need to be condensing boilers. With dual heat exchangers, condensing boilers are incredibly efficient at what they do and can help you save on your energy bills.

However, if it’s condensing replacing non-condensing, then there’s a slight chance that the flue would have to be relocated.

There are many different types of boilers. For a guide on each one, please use the following links:

However if you are looking to get a new boiler, you can get yourself a free, online quote from us today by entering your postcode below.

 

What is a Boiler Flue and what does it do?

A boiler flue is the large pipe that leads dangerous gases from your combi boiler out through the wall or roof. They ensure that combustion fumes are discharged carefully and safely into the atmosphere and with the boiler flue regulations, are vital to your central heating system working effectively. You can think of it like an exhaust pipe for your house, working hard throughout the year.

However, the position of your flue needs to be specific so that there’s no safety risk for those nearby.

Why are there boiler flue regulations?

safety first boiler flue installation

These boiler flue regulations are put in place to make sure that all installations performed are safe. The flues can be fed through the wall horizontally or through the roof vertically. This will be discussed in more detail with whoever’s installing your new heating system. The regulations themselves are becoming stricter to ensure complete safety from the Carbon Monoxide being dispersed outside.

For an informative NHS guide on the risks of carbon monoxide, click here.

Flue Positioning

As mentioned, you’ll have to consider where your flue is going in relation to the surrounding environment. The boundary line of your property must be taken into account, as there’s no way you’ll be able to have a flue installed if it’s close to any public walkway or near a neighbouring window. If the flue is fitted near the boundary line, there needs to be a minimum distance of 600mm between the end of the flue and the line itself. If not, then the installation won’t be allowed. Read on to find out more about boiler flue regulations.

 

Boiler Flue Regulations – Height

If you live in an end-terraced property and your horizontal flue is being installed near a public footpath, keep in mind how far it is from any walkway or area open to the public. While a distance of 210mm is encouraged, you can have your flue fitted with a guard for further protection to allow greater flexibility. The temperature of any escaping gases will be extremely high, so it’s easy to see how these regulations can keep every installation safe!

 

high boiler flue

Maybe not THIS high!

 

If a flue is installed through a wall, it makes it a lot easier to seal and make water tight. An experienced engineer will always try to keep you as informed as possible.

 

Boiler Flue Regulations – What about vertical flues?

vertical flue

A typical example a vertical boiler flue

As well as being installed horizontally, flues can be installed vertically through a roof, but come with their own issues. If you’re getting one installed, make sure that you’re kept informed by a professional.

The flue has limited access if it’s installed vertically. To overcome this, access panels will need to be installed across the flue pipe. This will always come in handy for future work as the panels will provide access for servicing or location faults.

Boiler Flue Regulations – What else is done to make sure the installation is safe?

If you feel a bit clueless about this, try and familiarise yourself with some key points for when a flue is installed through a wall:

  1. The flue must be completely sealed on both sides – This is done using sand cement, caulk or other sealants to make sure that no gases can escape.
  2. The angle needs to be correct – this is more important if you’re going from a non-condensing boiler to a condensing boiler. If it’s wrong, then you may have a drip escaping.
  3. Screws are used to secure any joints – All extensions, brackets and pipework need to be properly fixed together otherwise joints become loose and dangerous.
  4. Ensure both parties understand the exact length of the flue – When adding extensions or bends to the flue, you’ll need to be made aware by the engineer of how far it will run. For example, a 45 degree bend will add another metre to the overall length.

Also be aware that if too many extensions are added, there’ll be too much flue distance for the gases to escape and your boiler won’t be able to perform at maximum capacity. Maximum flue length does change between each boiler as well.

For example, for the Viessmann Vitodens 050-W 29kw it is 15m, but the 35kw version has a maximum of 20m. This is down to health and safety reasons, but every manufacturer will have their own criteria. For this example we’re just talking about the reliable Viessmann brand.

If you’d like to know more about some of the best boilers currently available on the market, why not take a look at one of our previous posts:

 

viessmann vitodens 050-w 29kw

viessmann vitodens 050-w 29kw

Boiler Flue Regulations – How much do flue extensions cost?

Details of flue extension costs should always be covered in quotes you receive so that you know exactly what you’re getting at the end.

However, you can always use the following details for a vertical flue as a basic outline of what you might be charged for.

The average vertical flue needs:

  • 1 x Vertical Flue Pipe – £63
  • 1 x Lead Slate – £30
  • 3 x Flue Extensions – £22 each
  • 3 x Flue Brackets – £15 for both
  • 2 x 45 degree bends – £35 for both
  • 1 x Firestop Plate – £10

*These prices are a guide only and are subject to change depending on the retailer.

 

 


Boiler Flue Regulations – Do I need Planning Permission?

You won’t need any planning permission if all parts and positions fall within the regulations. If they don’t, then you’ll need to discuss things further with a professional and qualified installer. This is the best way to be certain that your boiler flue meets the regulations.

It’s only when you have a new boiler installed that you might have to change your boiler flue position. Remember the points made in this article whenever you’re getting a new quote, and you’ll be good to go!

Make yourself aware!

knowledge awareness

Always make yourself aware of boiler flue regulations. If you’re getting a boiler serviced or re-positioned, be wary of professionals offering ‘so-called advice’. Pay close attention to phrases like ‘no longer meets regulations’ and keep yourself as informed as possible. Phrases like these are often said to encourage you to hand over more money!

stealing money

 

You’ll only really need to consider moving the boiler location when you’re getting a new unit entirely. Knowing when this is necessary will help you get the best quote, but as long as work is carried out by a professional Gas Safe Installer, you’re in safe hands.

 
41 replies
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Stuart,

      Thanks very much for the enquiry.

      When it comes to flue installations, you should always follow your manufacturer’s instructions. Every metre length of flue pipe should have a bracket for support.

      Kind Regards,
      The Boilerhut Team

      Reply
  1. ian william harvey
    ian william harvey says:

    Does a viessman flue extender work with any gas boiler …need to move flue higher up the wall > I will get an engineer to do it !! My boiler is a Rapid.

    Ian

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Ian,

      Thanks very much for the enquiry.

      In response to your question, Viessmann flues and extenders are only for boilers manufactured by Viessmann themselves.

      Kind Regards,

      Bryn
      Boilerhut Ltd

      Reply
  2. Gordon Mulholland
    Gordon Mulholland says:

    Need to for an extractor fan in kitchen area. Only possible place is directly below the combi boiler flue (Ideal 30+ model). What is the minimum distance between the two outlets required by regs?

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Gordon,

      Thanks very much for the enquiry.

      With regards to distance, we recommend using an ambirad flue termination guide such as this one: http://support.ambirad.co.uk/article.aspx?id=10724

      While this guide may help you, be aware that manufacturer instructions can still overrule this, so it’s also worth consulting the installation manual and contacting the manufacturer directly.

      We hope this answers your question!

      Kind Regards,

      Bryn
      Boilerhut Ltd

      Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi David,

      Thanks very much for the enquiry.

      The distance for these regulations will be down to your manufacturer. For example, Viessmann state that the top of the casing needs to be 250mm below a ceiling. We can’t speak for other manufacturers, so if you’re dealing with someone else, it’s best to contact them directly.

      Hope this answers your question!

      Kind Regards,

      Bryn
      Boilerhut Ltd

      Reply
  3. Dawn
    Dawn says:

    Hi I’ve recently had a plumber round to move some radiators and my next door neighbours flue is positioned opposite my front door facing my property the vent is high enough but the plumber told me it shouldn’t be in my view or facing into my door ? Which is my border ?

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Dawn,

      Thanks for the enquiry.

      As mentioned in the post, there needs to be a minimum distance of 600mm between the end of the flue and your property’s boundary line. If your neighbour’s boiler is old enough, it may be worth them getting a new one installed. From here, they can discuss with an installer the best position for their new boiler and flue without causing issues for you or anyone else.

      Kind Regards,

      The Boilerhut Team

      Reply
  4. Kevin Robson
    Kevin Robson says:

    I have a gas flue approx 1metre long
    horizontal going out of the back wall, this sticks out approx 300mm.
    This as been like it for about 10years now the engineer say it to long (regulations) and there’s seems
    to be a back fall, and it’s passed every year
    Your truely Kev

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Kevin,

      Thanks very much for the question. Certain flues and boilers allow for different lengths, so it depends on the manufacturer you’re dealing with as well. We’d suggest you continue discussions with your engineer, as they will already know your current situation. As long as they’re fully qualified, they’ll be able to give you all the answers you need.

      Hope that helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  5. Diane Bonnick
    Diane Bonnick says:

    I have had my boiler serviced. By British gas.The engineer has told me I need 3 clips fitted to the flue pipes.They are in the roof.
    I have just had a quote from them £172 for an hour and a half hours work.
    Does this seem high.
    Do I have to use British gas or can I get a quote from another gas safe company.

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hello Diane,

      Thanks very much for the question!

      Boilerhut has more of a focus on boiler installations rather than individual accessories. However, we suggest the best thing for you to do is to gather multiple quotes for various sources for comparison to help you come to a decision.

      Hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  6. Bernard Jerram
    Bernard Jerram says:

    Hi,
    I am having a replacement boiler fitted.
    My current boiler has a vertical flue which exits through the roof and I have been told that it will have to be moved as it
    exits too close to the chimney stack. Are there any regulations governing this?.

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Bernard,

      Thanks for the enquiry!

      We recommend following your engineer’s advice and avoid having a boiler flue too close to the chimney stack. Modern boilers use a combined flue and air intake so by putting them near a chimney, you’ll risk sucking those spent gases back inside.

      Hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  7. Jenna
    Jenna says:

    Hi,
    I have a boiler which has a vertical flue which cuts through plasterboard, then there is insulation the the roof void and it vents through a slate roof.

    The plaster board ceiling has bee cut very badly, to the point I can see the insulation. Should the be some kind of seal or intumescent collar to reduce the risk of spread of fire? I live in a flat which is a total block of 20.

    Many thanks

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Jenna,

      Thanks very much for the enquiry.

      As you may be expect, you will have to have this gap sealed off in the name of health and safety. This can be done using what is known as a fire stop plate. Bring this up with your installer if they haven’t already, as it is something that will need addressing.

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  8. Kev Bell
    Kev Bell says:

    Hi there
    The new owner of the flat above me has just installed a new gas boiler. The issue I have is that the flue extends out in line with my front door. When the boiler is on the condensate drips onto my doorstep, and if you’re unlucky enough to be locking or unlocking the door you too get wet. We spoke to the installer who said he would speak to the home owner and ask if he wanted a kit supplied and fitted but it would come at a cost, adding that if he wasn’t prepared to do this then it was our problem not his. We spoke to the home owner to no avail he just laughed and walked away.
    We have spoken to the local authority who say it’s not something they can help with as there’s no building warrant involved.
    Can anyone please advise where we go to from here
    Thanks

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Kev,

      Thanks very much for your question – doesn’t sound like you’re dealing with the most cooperative neighbour!

      Boiler flue regulations are put in place for many reasons, primarily to ensure a safe area for the flue to expel gases without causing risk to anyone nearby. It sounds like your current situation with your neighbour’s flue is in direct violation of that idea. If you’re feeling unsure, try and find out from the manufacturer of the boiler – they’ll be able to provide you with specific details on their boiler flue regulations that could help you make more of a case.

      Hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  9. Amy
    Amy says:

    We need a new boiler. The guy who gave us a quote said that all new boiler installations need a new flue too. We are replacing a 2006 Worcester combi with another of the same type. Do we really need a new flue too? It’s very expensive and it meets all regulations other than being old.

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Amy,

      Thanks very much for your question!

      You will need to replace the flue at the same time as your new boiler, even if you’re sticking with the same manufacturer. However, if you’d like more information on what must be considered for an installation, you can call us directly on 02920 099 898 and speak to one of our in-house experts. As well as this, you can also contact us via email at sales@boilerhut.co.uk.

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Amy,

      Thanks very much for the enquiry!

      If you’re looking to replace your current boiler, you will need to get a replacement flue at the same time – regardless of the condition. However, if you’re still in the process of choosing your next boiler, you can also speak to one of our in-house experts directly on 029 2009 8087. Alternatively, why not read through one of our previous articles below for further information?

      Viessmann vs Worcester Bosch
      Which Boiler is Best
      Best Combi Boilers

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  10. Luke
    Luke says:

    Hi there,

    I am thinking of getting a vertical flue installed through the flat roof of a new extension. The property is a ground floor flat and was wondering what the distance is allowed to be from the neighbours apartment upstairs. The closest opening window is 2.5m away but am not sure if it’s supposed to go above the neighbours roof line. Any advice would be much appreciated.

    Thanks

    Reply
  11. Eric
    Eric says:

    Are you able to comment on what the regs say for a non-condensing water heater, having a horizontal flue (5 degrees downwards) that runs along a wall? What distance must the flue end be from any other object it is blowing towards, specifically an adjacent wall?

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Eric,

      Thanks very much for the enquiry.

      We recommend contacting your manufacturer directly if you have any questions regarding your current flue positioning. However, if you’re already in the process of planning for a new boiler installation, you can get an online quote with more information by clicking on the following link: https://online-quote.boilerhut.co.uk/area

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  12. Ander
    Ander says:

    Hi, our open flue oil boiler has a chimney liner . The boiler is not suitable for converting to have a low level balance flue. We want to reposition the boiler to an external gable wall. There are no doors, windows etc on this wall so no problem with the location . Can a short flue be used to exit the building and terminate at about 2.7 m from the ground, Or does this need to run vertically on the outside of the building to above the roof ridge.

    Reply
  13. ANN BARCLAY
    ANN BARCLAY says:

    Hello

    A friemd has a boiler with a horizontal flue. She has now had cladding added to her walls which means the flue has a shorter extension from the original wall. When the plumber came to service the boiler he said he couldn’t as it was now illegal. How long should a flue extend from the external wall. The bolier is very close to the flue egress.

    Thanks

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Ann,

      Thank you for the enquiry.

      If you’re unsure whether or not you’re current flue position is affected by the regulations, the best thing for you to do is contact your manufacturer directly.

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  14. Mike
    Mike says:

    Hi guys. We currently have an old (but serviced and working) gas boiler sat next to a hot water tank on what is currently an external wall. The flue goes out through the external wall but we are looking at getting a ground floor extension with a flat roof and have been given conflicting advice. Person 1 states that the boiler will need to be replaced and moved to a new external wall. Person 2 states that we can just add an extension to the flue of a few feet to go out of the new flat roof of the extension. Be grateful for your thoughts..

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Mike,

      Thanks very much for the enquiry. Unfortunately, we’re unable to offer advice on flue installations. Our best suggestions would be to contact your manufacturer directly for specific information.

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  15. Frances
    Frances says:

    We are buying a terraced house with a 28 year old combi boiler in a low level cupboard in the first floor rear extension. The outer face of the side wall of the extension is the boundary, and the flue goes horizontally through this side wall and discharges a little way away from and below the window sill of the neighbours first floor bedroom, The Building regulations diagram does not make clear if it it permissible to discharge flue gases straight into a neighbour’s land. We expect to have to replace the boiler soon, and know the new boiler will have to be a condensing model: can it be replaced with the flue discharging in the same location?

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Frances,

      Thanks very much for the enquiry!

      If you have any questions regarding options for the installation of your new boiler, please contact our office on 029 2009 9898.

      We hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply
  16. Jane
    Jane says:

    My flue is high up on side of wall over neighbours drive Neighbour has no problem with it. If I were to get new boiler can I still put flue there

    Reply
    • Bryn Lloyd
      Bryn Lloyd says:

      Hi Jane,

      Thanks very much for the enquiry!

      There are certain details that need to be taken into account before an installation can be approved. If you’re planning a new boiler, we’ll be happy to answer any questions you have, just give us a call on 029 2009 9898!

      Hope this helps!

      Kind Regards,
      The Boilerhut Team

      Reply

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *