we have a few fire places and chimneys we don't use (victorian terrace). dh thinks we should just block them up, but I read that can cause condensation problems. I think we should keep them but do something they are part of my zombie plan
we want to minimise the draft and the mess (grey dust falling down from them) but also want to be able to make them usable quickly in case the zombies are on the loose
chimneysweeps, gas-fitters and plumbers use a thing called a smoke-bomb. It is like a firework that makes lots of visible smoke but little flame or heat so it is not very likely to cause a fire.
I would hope it has been formulated so the smoke is not harmful. You might be able to get them at a plumbers merchant. There are little smoke pellets that you might find at a DIY shed, they might be too small for a chimney test.
This is very interesting, our kitchen has a chimney breast which is covered at the top, but ventilated, while at the bottom it's completely boarded, not flat against the wall but horizontally, the whole fireplace is out and we have an alcove. How interesting that this may cause condensation.
(If you still have the fireplaces looking attractive then putting bulk loads of thick candles looks really nice. )