I hope there's a chimney sweep or stove installer here who can answer my question.
We have just thrown out our combination boiler from '61. It will now be an Air/Water heat pump in the boiler room and thus we sealed the old connection in the chimney with fire-resistant mortar and the old fire-resistant 'bricks?' that were at the bottom of the boiler.
Now, for a backup heat source, we want to install a wood-burning stove of about 10kw in the living room, which is on the other side of the wall. This wall is about 10-20cm behind the chimney, which is built and stands on the concrete slab in the boiler room. The wall is combustible since it's an old outer wall made of logs/timber, which in the boiler room is covered with non-combustible board and the side facing the living room is probably tretex or masonite. I haven't checked this, and in any case, it's combustible material in the wall that causes issues since we want to have a passage from the stove to the chimney. How can the passage be solved most easily so that it becomes approved and thus not a fire hazard?
