Gas Safety Certificate Failed by Boiler flue not sealed?

Gas Safety Certificate Failed by Boiler flue not sealed?

13:38 PM, 29th October 2020, About 3 years ago 8

Text Size

I have just received a failed gas safety certificate due to the reason of “Boiler flue not sealed”, for a property with new boiler installed exactly two years ago.

The strange thing is that for the past two years the gas safety certificates were all well and good, without anything changed.

What’s my best action here?

Is it best to find contracts to “seal the flue” or find another contract to do gas safety certificate?

Many thanks


Share This Article



15:12 PM, 29th October 2020, About 3 years ago

Get the contractor who did the CP12 to explain exactly what the problem is. It could be as simple as re-sealing the flue at the outside of the property. If the flue has a long run with more than one section you must be able to get access to check the seal integrity at the joint of each section..

Ian Narbeth

10:11 AM, 30th October 2020, About 3 years ago

I emphatically would not "find another contract to do gas safety certificate". That is only dodging the problem. Just suppose you found another engineer who missed the issue. Then suppose there is an incident, perhaps a carbon monoxide leak that kills or injures someone. When the truth comes out that you knew about the failure but did nothing, well, you are facing a manslaughter charge and civil liability.

If you had the new boiler installed, contact the installer and explain the situation. Ask them to reinspect and to pay for the necessary remedial work. If you purchased the property subsequently, you will probably have to meet the cost yourself unless you had the boiler and flue inspected and this was not picked up.

Dennis Leverett

10:41 AM, 30th October 2020, About 3 years ago

I had a similar problem a couple of years ago when a tenant had a smart gas meter installed. The installer said he would have to shut the system down as not safe because boiler flue not sealed. The tenant refused and got in touch with me, the installer said it was not sealed where the flue goes through the ceiling into the loft. By the time I got there the installer had gone, right jobs worth apparently. There was a one mm gap around the pipe to ceiling in the boiler cupboard, had he have bothered to look in the loft he would have seen a sealing plate in place which actually was not a requirement. A few days later got a letter from the Utility company saying for safety reasons they had reported the fault to whoever. My gas engineer very kindly came round to inspect and in his words "it was typical of these installers and he was wrong and failed in his job by not looking in loft" I wrote to the Utility company asking for an apology and compensation. Three times I wrote by recorded delivery and never got a reply. So first of all find out where not sealed. For an installer not seal the the flu joints is very serious and unlikely because of the possible consequences.

Laura Delow

11:33 AM, 30th October 2020, About 3 years ago

I too had an identical problem the beginning of 2019 & on reverting to the original installer, he tried to tell me that when he installed the boiler in 2016 it wasn't a regulatory requirement back then & that he could do it now but charge us for doing it. I was suspicious so I contacted the Gas Safe Register by email who I found most helpful. In summary they told me that nothing had changed since 2016 with regards the requirements to correctly install & seal a flue & they would expect the original installer to carry out the remedial work as this should have been done correctly at the time of installation. We rang the original installer back & told him we'd contacted the GSR & the detail of what they had confirmed in their email, and he reluctantly returned & sealed the flue without charge.
I suggest you use the GSR as leverage to do the same. Their contact email is

Mick Roberts

16:27 PM, 30th October 2020, About 3 years ago

It's not strange, just one plumber han't done their job right.

Get first one back if u can, if not get boiler flue sealed today, not next week. Like Ian says. Very simple.

When u got as many houses as some of us, u realise all plumbers are different.

And as Dennis says, could be that too. I've had many of them.

Jireh Homes

17:16 PM, 30th October 2020, About 3 years ago

Similar situation on a recently installed boiler, that sealed on outside of wall but left large gap on inside wall. In this case gas technician noted advisory with recommendation to "finish off the job properly"


22:34 PM, 31st October 2020, About 3 years ago

Reply to the comment left by Ian Narbeth at 30/10/2020 - 10:11
I see your point Ian, but this is the problem with these "bogus" electrical reports. These "inspectors" clearly are not competent, (a requirement). The report is incorrect, you can show its wrong, the old chestnut, gravy train being "a new fuseboard" and you end up paying it to avoid the hassle.

Ian Narbeth

8:56 AM, 2nd November 2020, About 3 years ago

Reply to the comment left by 2391 at 31/10/2020 - 22:34
Dear 2391, may I call you Anon?
Nothing in the original post suggested it was a bogus gas safety report. The landlord picks the inspector. He should be using a Gas Safe (formerly CORGI) registered person. Having done that, a landlord should err on the side of caution, even if there is a cost and even if replacement work gets done earlier than it might have been. As I explained, the consequences of not taking action may be disastrous.

Leave Comments

In order to post comments you will need to Sign In or Sign Up for a FREE Membership


Don't have an account? Sign Up

Landlord Tax Planning Book Now