Closing Fireplace

[mibazza]

Hi all,

I want to do away with our wood burning stove and close off the fireplace. Our house is heated by gas central heating and we never bother to put the wood burner on despite having crates and crates of wood. We want to close off the fireplace so that the opening is closed and plastered flush with the rest of the wall. I'm planning on ripping out all the exisitng plasterboard on that wall as it has damp bridging where its touching the stonework. I'll remove the hearth and build new studwork to cover the existing opening. My question is what do I do with the existing fireplace cavity behind it? The fireplace has a steel plate fitted inside the chimney breast with a pipe for the stove to connect to. Can I just cap off that pipe and cap the chimney pot on the roof then line the internal fireplace space with insulation? I've only ever put studwork up for an internal cavity wall so I'm unsure what I need to do for an external wall. The existing external walls are insulated with polystyrene (way before be bought the house). This is the only fireplace on the chimey breast.

 

[oldbutnotdead]

Seems a shame but up to you.....best practise is to ventilate the stack top and bottom. The liner doesn't need ventilating but the brickwork does, if you don't you can end up with damp patches showing through the plaster. Hit and miss vent at the bottom in the stud wall, take the inspection plate out of the register plate (to allow airflow), cap the liner, create an air path at the top of the chimney (airbrick in the side works well).

Or (Plan B)- just leave the woodburner there, what else will you use that wall for? Interested by the thickness of the plaster on the hearth, is there insulation behind there? (bit of a no-no for the woodburner in that case)

 

[mibazza]

The register plate doesn't have an inspection plate, its just a steel regsiter plate covering whole of inside of chimney breast with flue pipe coming through the middle of it. Not sure if plasterboard around fireplace is insulated, I guess I'll find out. The wall is going to have a long low electric fire built into it at low level with 65" TV mounted above it. I'm building the stud wall out slightly to accommodate the electric fire as its going to sit central to the wall which is not the same as the existing hole for the fireplace. The wall will then step in above the fire back to the existing wall depth thus creating a mantlepiece above the fire and insetting the TV from the front of the fire. Just a 2kW fire and it will be more for effect than heat, it'll rarely be used for heating the room.

 

[oldbutnotdead]

Hmmm, tricky. The usual conflict between reducing draughts to keep the place warm but having enough airflow to prevent damp building up. Best bet might be to remove the register plate and replace it with a bit of ply the same size with a load of holes drilled through it. Hit and miss vent hidden behind your electric fire and off you go. 65" That's massive- you'll definitely get square eyes viewing at that short distance

 

[mibazza]

If I remove the register plate will the chimney breast not be filled with vermiculite or will there be a liner around the flue pipe filled with vermiculite? Either way when I remove the plate will I not get a load of vermiculite falling out? And if theres no existing ventilation in the chimney breast will there be damp already in there? I can't remember seeing any fixings for the register plate, I'm not sure how its removed and I'm not at home at the moment but I'll look when home next week.

 

[mibazza]

Already got the 65" TV, viewing distance will be almost same and its fine at the moment.

 

[oldbutnotdead]

Good point about the vermiculite- some do, some don't. Best way to check may be to disconnect the flue liner from the woodburner then push the liner up into the chimney and see what falls out......if the flue has been packed with the stuff then very little point ventilating it & it'll be doing a decent job insulating the flue. Fixings for the plate usually self-tapping screws on the edges into bits of angle screwed to the brickwork.

 

[mibazza]

When you say the flue liner connected to the wood burner, you mean the black pipe? See pic. I don't there is a liner? If there is its only above the register plate, theres only the black stove pipe comes through the register plate. I'll have a look for angles drilled into stonework but I don't remember seeing them.

 

[oldbutnotdead]

Yeah, the black pipe ought to connect to a flue liner above the register plate. The angles will be above the register plate as well, all you should be able to see are screw heads.

 

[mibazza]

Ok cheers, I'll have a look when I'm home and remove the register plate if I can and see what I have. Our bedroom is above the same wall and I often hear stuff crumbling and falling down inside the wall/breast. Its pretty disconcerting so I'd like a look in there to see whats going on, house is stone built circa 1890.

 

[johnny2007]

Before you do anything, spend an evening burning some wood in there.
You might like it.
In my case, when we have the fire on, the radiators on entire ground floor shut off (set at 18 C), so massive saving of energy 50% and some relaxing time looking at the fire rather than the phone...

 

[mibazza]

We've had the house for several years and have used the log burner on and off. But its not used much and I actually think we lose more heat from the fireplace than we gain with the few times we use it. The stonework and register plate are always way colder than the room, so we're losing heat.