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How to Repair Funnel in Chimney Flue After Removing Gas Fire

Postby cazzalaw » Tue Aug 21, 2018 10:07 am

See pic.

I have removed a gas fire from the living room and I want to restore it to use as a "real fire". (The gas pipework has been removed and capped off).

I originally thought to knock out all of the "funnelling" that had been applied and bring the whole thing back to the original rectangle of brickwork but I just couldn't get the pickaxe in there so I'm now left with a part-demolished "funnelling" which I want to restore (you can probably tell that I'm not a DIY-type person. I'm just doing the best I can whilst I'm time-rich-cash-poor...)

Anyway, I'm now left with some sizeable holes (one about 3 fist sizes) that need to be refilled. I just don't know what to fill them with - lots of conflicting advice on the websites.

The guy who came in to sweep the chimney after the gas fire was removed advised me to fill the holes with a mix of 4 parts sand, 4 parts cement and 1 part lime.

Other advice I had was to fill the holes with a lime mortar mix: 3 parts sand, 1 part NHL 2 hydrated lime. I mixed this up yesterday and part filled the smaller holes with this yesterday but this morning I notice that the lumps of lime mortar mix that fell off as I was applying it have a VERY CRUMBLY TEXTURE and I just don't see how this mix is going to withstand having coal and wood chucked at it. Surely it's just going to get damaged very quickly and fall apart once I start using the fire?

Please can someone advise me what to fill these hole with so that I end up with a smoothy funnel for the smoke to go up when the fire is in use.

I still have some natural hydrated lime left over (1kg of it) but I understand that this "goes off" quickly and will need to be used in the next couple of days!

I have various materials that I could use for this job: Sand, cement (Blue Circle Mastercrete) and the "rubble" that I originally knocked out with the pickaxe and broke tip into small chunks.

I also have a 5kg tub of ready-mixed firestone cement. Surely between this lot I can repair the hole in the chimney flue?
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