Hi guys, I'm new at this so please tell me if I'm not following protocol. I am about to start on a self build project the start of which is to remove an existing outhouse type extension to the rear of the property. As part of this I want to remove an old chimney. This wouldn't normally prompt me to ask a question as the process is common sense and well documented elsewhere, however, my chimney appears to be incorporated between the two cavities of the wall so I will need to fill in the outer cavity as I go and I haven't been able to find any other discussions of removing this type of chimney. My question is should I approach this from the top or bottom? Obviously I'll take the stack down from the top as the first step but once that is gone, from a removal point of view it would be much more sense removing brickwork from the top but that makes re-bricking the outer wall challenging at the very least. From a bricklaying point of view obviously working from the bottom up makes more sense but then I have the issue of supporting the remaining stack as I go. The chimney is square and two bricks wide/deep. Does anyone have any advice on the best way to approach this? I realize that this will effectively leave a small cavity width chimney after the job is done which will need venting top and bottom. I'm actually thinking I may put some conduit in there as I go to make a riser for getting cables into the loft. Thanks in advance, Alan.
I think you should you remove stack down to roof line, then you might get a clearer picture of it's construction from there downwards. Proceed with caution,I've been caught out more than once with demolishing old chimneys, always expect the unexpected. I've done chimneys were I started from the bottom, supporting brickwork above with strongboys & acrows, & building up, doneit from top down using needle beams & acrows to support brickwork, it all depends on the construction & there is no standard construction with old buildings. How old is outhouse.
If you can try and keep this as it may be stiffening the outer skin of the wall. If you are removing the chimney all the way down, there shouldn't be anything that needs venting afterwards ?
Assuming the chimney does use the inner wall the cavity must be blocked off all the way up both sides so by filling in the existing line of the outer wall there would be a cavity thickness 'chimney' left and I assumed this would want venting?
So this is what you have now And this is what you need ? As you rebuild the wall back up, there will probably be an opportunity to remove the odd brick from the red section, a half brick every few courses from either side would be enough to get the air flow going between both sides. Either that or remove the red section completely and use screw in wall ties from the outer skin to the infill blocks. This way you get a complete air flow and reduce the risk of damp crossing the cavity. these are quite good and realy strong http://www.screwfix.com/p/sabrefix-screw-ties-25-pack/31633
It's actually like your second diagram now (nothing showing inside the house) and I want to remove the outside part. I assume it may have been a flu for some sort of heating in years gone past. I'm not sure which side the opening was as both sides are currently plastered. Another complication that I have just thought of is that there is a door immediately to the side of the chimney so there will be a concrete lintel in there too.
If the wall is quite long, you have to be very careful, because the residual part of the chimney could be working like a buttress and strengthening the wall.
Which what I thought you had,minus the 3/4 outside & you also get them where there no 3/4 brick outside showing, flue is built completely within wall.
Thanks for your advice guys! If I do take this out from the bottom what would be the maximum height section I should do at a time (supporting the above brick work with acro's etc)? This is assuming that my belief is correct that the inner wall forms one side of the chimney breast (no breast showing inside the house) and the outer wall is thus tied into the inner wall all the way up to form the chimney. As I work up I would take out the bricks closing the cavity to open it back up as suggested above. I'm fairly confident that I'm correct about the use of the inner wall as the dimensions of the stack strongly indicate that this is the case.
Hi apritcha, sorry to revive an old thread. I'm in almost exactly the same situation and was wondering how you got in with the job? For me, the "outer" part you wanted to remove is is inside my side extension. Thanks
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