Drilled into my flue, need advice

I could really do with a bit of advice. I've just moved into a new house and was drilling above the gas fireplace to put a fitting for a mirror. However I seem to have drilled through the flue as it was right behind the plasterboard.

I know this is a stupid mistake but its done now so I just want to put it right.

The house was built around 1978-80, the hole is about 10-12mmm and I would prefer to be able to continue using the fire.

When looking into the hole with a flashlight the flue appears to be a bluish aggregate not sure if its Concrete or blue cement (Asbestos??). I'm sure I've gone into the flue since I can see the blue cement and If I put the fire on to test I can smell the fumes throught the hole.

A friend said because its a small hole I should just fill it with some KOS flue cement and not worry about it.

http://www.everbuild.co.uk/products/84,Purimachos Products/86,Fire, Stove & Flue Cements/1

Is this advice sound or is a more substantial repair needed.

Thanks for helping

You need to get a Gas Safe registered engineer in to assess the damage and to id the flue materials.Fire cement can be used to repair minor holes but the flue needs to be tested afterwards.Be prepared to expose a bit more of the flue by removing some plasterboard,and DO NOT use the fire until proper repairs have been completed.

Just to add I've done a little research and it looks like I have a Class 2 precast flue as I have a ridge vent on the roof, so it looks like the flue marterial is Concrete and not Asbestos which I first thought it might be.

Thanks for your advice, looks like I may have to bite the bullet and pay for my mistake.

Whats the likely worst case scenario for the repair, cutting a hole in the wall and replacing the section of the flue?

It can all depend on the condition of the rest of the flue - you could get away with drilling and cementing on a flue inspection plate to cover the hole - (cement the back edge of the plate and stick it on over the accidental hole and then drill the plate in the corners and screw it tight to the flue.

However there is the likelihood that the screws will just crumble the flue when you screw them in - you could simply fire cement the plate on and heat it up with a heat gun to get the cement to dry and then go over the edges with a heat resitant silicone.

Or replace the section of pipe - up to you really.

All useful info, but I reckon he's prob done it by now.

45yearsagasman said:

You need to get a Gas Safe registered engineer in to assess the damage and to id the flue materials.Fire cement can be used to repair minor holes but the flue needs to be tested afterwards.Be prepared to expose a bit more of the flue by removing some plasterboard,and DO NOT use the fire until proper repairs have been completed.

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i agree to his opinion and his solution

Ibanez29 said:

within the flue pipe wall is a blue chalk usualy if it bust's out the length of flue is unusable. If you have a condention boiler this will affect the performance.

The length of flue pipe should be replaced but as it is plasterboard in front of it should be easy enough. Big problem with gas though is carbon monoxide and if you don't have an alarm get one, even when you get the problem sorted.

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cobblers mate