Rebuild "funnelling" within chimney flue after removing gas fire

[smiledotcom]

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?

 

[stuart45]

It needs to be rebuilt properly with a fireback and throat etc. Flue needs testing.

 

[smiledotcom]

Thanks for your advice.

Any idea how much all of that would cost to pay someone to do that?

 

[stuart45]

Depends on whether the flue needs lining. 3 or 4 hundred to do the work to the fireback and form the throat and gather probably, but prices vary in different areas. Really needs to be signed off by HETAS or Building Control.

 

[smiledotcom]

So definitely not a DIY undertaking then. Shame cos I've bought so many different materials to do this!

Many thanks anyway

 

[stuart45]

It is possible to DIY, but it does sound like it could be stretching your skills a bit. Getting an open fire right is a bit of a science.

 

[smiledotcom]

Yeah, I'm sure it takes a lot of experience to get it right. I remember the chimney sweep telling me that the flow of smoke needs to be able to swirl upwards nice and easily into the funnel properly otherwise some of the smoke will exit into the room.

I just thought that if I gave the funnel nice smooth surface, and covered it all in special Firestone cement, that I had covered all my bases. I'm guessing that the narrow funnel that is there now was created not for use as a real fire but specially for the gas fire when it was installed in order to fill the gaps around the side of the original rectangle of bricks.