Unknown prob with chimney

Berry Nice

I have a stove in my sitting room but whenever I light a fire thick brown pungent liquid runs down from the chimney even if its not raining. We have resealed it several times but it doesn't seem to help. Some have said I just need a cowl but others have said I need to get the chimney lined which is a much larger more expensive job. If anyone has had a similar problem any advice would be much appreciated.

Spear

Moved from N&F.

DoneDL

It does sound like there is a lot of tar build up in the chimney, it would be worth contacting a reputable chimney company for advice as I don`t think installing an insulated liner would prevent the existing tar running down the chimney. Are you sure that previous sealing compounds were suitably heat resistant.

rpmcs

In my experience this sounds like a cold chimney that has condensation running back down as hot gases rise, best thing to do is reline with flexi flue and backfill with vermiculite, this will keep the chimney insulated and even if condensation does occur it will burn out in stove because with liner all joins point in ward towards stove, it will also increase draught in stove to add to better efficiency,
a cowl is only for rain and this does not sound like your problem,

Billy Bunting

Dito to that, cold flue, steel liner should fix it.

heinbloed

The substance is called creosote. A carcinogenic substance which evaporates when heated up above the boiling point.

Stick to the advice of DoneDL, I don't know why a liner would solve the problem.
If creosote can be liquified (in the OPs case) it can be evaporated, going up the chimney and out of the house.
Bringing in a new liner and filling the gap will stop the air moving up along the polluted chimney's surface, the evaporation of the creosote will now go through the existing chimney.Into the house.

Contact a reputeable civil engineer, a chimney specialist who understands the laws of physics and knows the risks involved when enclosing combustable, carcinogenic substances in an reactor which is supplied with heat and air.

Bringing in a new liner will not solve the problem, i.e. the presence of creosote. React fast, the substance is also combustable, a fire risk.

Solnskaya

Heins reply is technically correct but also practically impossible and also a little alarmist. Burnt toast will give you cancer, etc. As I deal with a lot of historic properties at work, I encounter this problem regularly. The real issue here is that your fire is producing tar, and your chimney is probably letting in rain. This is dissolving the tar and because you have an old-tech, leaky chimney, it is leaching through the cracks and appearing on your walls/ceilings. Get your chimney lined and install a really good cowl. The leachate needs to be cleaned off, it may well re-appear, wash it off again. It's much like coal-tar, and people wash their hair with that, etc etc. You are probably looking at a bill of €3-5k depending on the size of your home. Your insurer may or may not assist, depending on the type of policy you hold. Soln.

Billy Bunting

Solnskaya wrote: »

Heins reply is technically correct but also practically impossible and also a little alarmist..

Yep! thats Heins. :rolleyes: