Cast iron back solid fuel fire

[johnygl]

hello, iam replacing my gas fire with an open cast back insert we used have a coal fire so everything ok we have had chimney swept and smoke tested, i was just wandering if it would be ok to backfill with vermiculite after fire has been put in ?? and if so how much of it wil i need

 

[gday2uk]

Yes, ideal.
I think it only comes in 100L bags which will be ample.
About £8 form build centre. If you're mixing it with cement to form a slope on top make sure it is thick otherwise it will break up with the heat.

 

[johnygl]

Hi Thanks for your answer would it be possible for you to expand on the cementing on top ??? thanks again johnygl

 

[sootylum]

6 or 7 parts vermiculate to one part ordinary portland cement, don't make it too wet, use this to fill in the void at the back of the fire. For the flaunching at the throat of the fire use a lime mortar mix this will allow it to expand and contract with the heat.

 

[johnygl]

Hi sorry to be Ignorant,Flaunching at the throat of the fire is this where the ash pan would sit . and if so i would make it level with the hearth slide the fire in then fix to wall then back fill through vent opening with stiff cement mix with vermiculite mixed in and not just vermiculite Flaunching
The flaunching is the weatherproof top of a masonry chimney (often concrete) which sheds the rainwater off the top. It is also used to secure the chimney pots I looked it up and found this now iam confused .com lol

 

[gday2uk]

Flaunching / haunching is a generic term for sloping cement at it's very basic level.
You are almost there except make your level up to hearth with grit and cement (or post-fix if you want it to go off quick).
Fill the void behind with stacked bricks before placing the fireback and once fixed fill the remainder with vermiculite, this allows for expansion and contraction. Stack the bricks higher then the opening so you can slope down the flaunching around the throat of the fire (the bit where the smoke goes up)

Read this and things might be a bit clearer http://www.antiquefireplacecompany.co.uk/fitting.php