On Jul 5, 9:04 pm, (Andrew Gabriel) wrote:
In article .com,
bp writes:



Hi,

I want some advice on blocking up the inside of a fireplace.

I live in an old terraced house which has a chimney and fireplace.

I have recently had the chimney wall and fireplace all re-plastered.
I dont have a fire and I dont want one. The fireplace is currenlty
open and it has been plastered inside. I have had it swept.

I just want to keep it like that as a decorative feature. But I need
to block off the inside to prevent soot from falling down into the
fireplace floor. I know I have to keep a ventilation hole

I've done exactly this. If it backs onto an outside wall, I would
suggest you ventilate the flue to the outside rather than the
inside. Otherwise you'll lose up to a kW of heat up the chimney
in winter.

I put an air brick from the flue to outside a few courses of bricks
above the top of the fireplace. I then blocked off the flue using
a piece of plasterboard in the top of the fireplace glued in place
with bonding coar plaster. When fitting it, I put a layer of loft
insulation on top of the plasterboard, partly to prevent it getting
cold and forming condensation, but mainly to cushion any debris
falling down the flue to reduce chance of it damaging the plaster-
board. The back wall of the fireplace was only a single skin brick
wall, and to prevent that getting cold and forming condensation and
mold, I lined it with 25mm cellotex and then plasterboard, and
plastered the whole inside.

I dug out the floor of the fireplace down to the slate damp course
in the brickwork, fitted a damp proof membrane, layed about 6" of
cement and vermaculite insulation and brought it up to floor level
with mortar. This should enable it to be used for a fire in the
future (if the flue is reestabled and the cellotex removed).
Fireplaces often relied on regular fires to keep damp out of the
base and hearth, and without fires, mine was slightly damp as the
infill wicked moisture up from the earth.

I dropped a lighting cable down the flue from the loft, to enable
a concealed light to be fitted in the fireplace.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Bhupesh,

I see, it does sound very similar to what I have done upstairs. On the
side of the plywood that face up into teh chimney I have treated that
with sonme external wood preserver, the bit that is visible, i've just
used standard satin paint, or whatever you want.

As for any small gaps that were left around the edges, I have used
decorators chaulk to seal those.

I forgot to say in my original reply that I put a vent in the plywood
too, just s standard plastic one, and the lighst either side.

I must admit, getig the batten in place was the hardest part and I did
curse quite alot while doing it...I had to drill at a slight angle as
my drill was too bit for teh chimney hole, but I wasnt worried too
much about teh neatness of the batten, as long as they were secrured
well, they are now hidden by the plywood. I didnt find a way to attach
the ply to the front arched edge as there was no way I could drill up
there, but the ply seems to hold well enough along the 3 edges.

When I said Mitred beading, I used standard wooden beading, the right
depth for the plaster and attached a stip up each side of the opening,
in the room. To create teh arch effect at teh top I cut teh battem
into 5 mitred lenths, which when attached creasted the arch i required
all the way around. This was also trickey as the old plaster was very
deep and varyied greatly in depth around the opening.