damp 'slime' Damp can be a major issue in the home. Find answers to questions or post your own here.

[greggpeg]

hi hope someone can help...my house has depeloped some damp on the internal side of the chimney breast.i have checked for leaks from the radiator above in the loft but that's ok. the weird thing is on the outside of the house there's some greasy oily shape that looks like it follows the shape of the chimney.it goes from about half way up upstairs almost to the apex.could this be something to do with soot being drawn through the wall???? has anybody else had this issue? is it damaging to the bricks and how can i fix this problem? cheers for reading,hope you can help.gregg

[no1son]

You do not mention if this chimney is in use or not but I recollect a job I did a few years ago on a coal fired boiler which utilised the chimney for its flue.Smoke from the flue had been entering the room where the boiler was located for a number of years but the old farmer put up with it.When I checked out the flue I dislodged a chimney sweeps brush and thought the problem cured,I did a smoke test and the smoke came back into the room,rodding the flue from underneath was a waste of effort because of a further blockage higher up.When I checked out the stack from the roof I found a birds nest had been built inside the stack on top of a couple of bricks,removing these cured the smoke issue.It was at this time I noticed an oily substance around the stack which turned out to be the products of soot mixed with rainwater falling through the stack because of a lack of ventilation and updraught.If your chimney is not being used check there are vents top and bottom and the condition of the brickwork around the stack is sound.

[greggpeg]

hi the chimney is not in use.i think it has been capped off aswell.i put 2 new vents into the chimney this summer,one at waist height and the other well up about level with the floor in the loft.we have just gone back from gas to coal in the house but not in this chimney like i said.that's in the other chimney in the living room. there is a strong foil like liner in the chimney-i found this when i removed the bricks for the vents. hope this helps a bit more.gregg

[no1son]

Greg,positioning of the vents should be, a) approx 12" from floor level above skirting boards for the lower vent with the angled face pointing downward.b) The second higher vent should terminate as high as is possible external to the property and not in the loft space.
If, as you say,the chimney has been capped off and you are now using coal bare in mind that the flues from each room converge at the stack,this will be shown in the loft by an inverted Y shape on the side of the house bearing the chimney ( without knowing Im assuming it is standard ).You should have at least one flue terminating in a pot/flue terminal.A general rule is if the stack is capped off ( pots removed and replaced with a bed of slate and mortar over its area),and the terminal is positioned central then it acts as a vent for each flue.If on the other hand it is positioned off centre it indicates it is a terminal for that flue,your mention of a flue liner tells me there was a "back boiler" using that flue at some stage and if this was the case then any terminal could be still connected to that liner.In theory it is possible to have spillage at the point of convergence of the flues and the air vent you installed is acting as the termination point for your coal burning appliance,I would suggest contacting a local chimney sweep to investigate further but make sure he is corgi registered.Wish you well.

[greggpeg]

thanx for your time and effort,it's hard to describe and understand just using words.cheers

[TheDoctor5]

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