he suggested that the chimney wouldn't function correctly and that fumes could seep up the bricks somehow and then filter into the loft. (I'm paraphrasing what my wife has told me the installer said).
What I can't understand is how or why the damaged bricks would affect the chimney, even if the bricks have vents in them the fumes can only reach the next layer of mortar surely? Do I need to take out all teh damaged bricks and replace or is he thinking something else is wrong.
I'm considering dropping a carbon monoxide detector into the loft to see whether anything is seeping for the time being but just don't fancy damaging the chimney any more than the cowboys did iin the first place.