water dripping behind fire?

[katy may]

We had a big patch of damp on the chimney breast, which started half way up and was to one side. I called out a damp expert (there's something wrong with that term!) who advised we got a cowl fitted to the chimney. This was duly done but one the day it was fitted it rained heavily and I could hear water dripping behind the fire place, which I'd never heard before. I rang the damp people who said there was no way it could be coming from the cowl but could be from the chimney pot next to it which relates to the bedroom chimney (no fire there, it's been removed) and this is somehow dripping into the living room. Does this make sense? Do I need to get another cowl fitted? Could this have any bearing on the cracks in the bedroom chimney breast (see earlier post), although the bedroom chimney isn't damp.

Thank you

 

[Big G]

Are you using any of the chimneys?

If what the damp expert is saying is true, the mid feathers in the chimney may have gone.

Was the noise of dripping actually the sound of water dripping, or could it have been water simply hitting the cowl? We had one of our chimneys lined with an aluminium liner and a GC1 terminal fitted. Since then, we can hear the rain striking the cowl.

Are you doing the work yourself (fitting the cowl(s))? Are the chimneys used?

I would maybe smoke test one fireplace and see which ‘pot’ the smoke comes out of.


G

 

[markthebuilder]

they may have fitted the cowel to the wrong flue,
you may also need the chimney properly flaunching
What sort of fires / fuel are you using

 

[katy may]

We are using the Living room fire place. The damp men put a bomb up the chimney and checked which pot was being used. They reflaunched too. It's a gas fire.

Thanks for that comment about hearing the water hitting the cowl, it's raining today so I'll listen later.

 

[joe-90]

Most such problems come from the exaust gases of the boiler. Gas + oxygen = CO2 + H2O. The water condenses on the walls and drips down.

If it's not that and it is just a bit of rain making a direct hit and not touching the chimney walls - forget it. That's been happening since the Iron Age.

 

[Big G]

Is this chimney on an outside wall? I did a Google regarding the products of combustion (water) condensing on the inside of the chimney.

The general consensus was that although water vapour is produced, it should not cause a problem unless there is another underlying problem with the chimney. If the chimney is not drawing the products of combustion away quickly enough, this can cause condensation. Most likely causes of this are a cold chimney (hence the question about the outside wall) or a too large a diameter chimney. Another possibility is that the room that the chimney is in is very cold making the chimney work in reverse.

I would think that you are getting water ingress from somewhere – either the cowl is not sealed or from the other chimney.

I seem to remember that you can get a CCTV survey of your chimney – I wonder whether this would pinpoint the cause. May be costly though.

Could the damp patch be the existing damp that has not dried out yet?


G

 

[katy may]

Thanks all. Have got a chimney specialist coming out soon to deal with it. It rains a lot in Yorkshire and the noise is really really annoying!