If you have a new account but are having problems posting or verifying your account, please email us on for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact

Damp mould issue

  • 12-12-2021 8:56pm
    Registered Users Posts: 150 ✭✭

    There seems to be a damp mould patch where the wall meets the ceiling. I've checked the attic and can't see any signs causing it.i was thinking maybe has something to do with the guttering..have to get a ladder to inspect that part..could there be any other issues causing it..I've attached a picture showing where it is.



  • Registered Users Posts: 414 ✭✭Emma2019

    What's the ventilation like in the room? Mould can just as easily be caused by moisture condensing on a cold wall than a leak.

  • Registered Users Posts: 150 ✭✭DamoNolan

    There is a air vent in the room as the house has gas so one in every room.ill have to check the vent and make sure its not blocked up by pervious owner.

  • Registered Users Posts: 2,832 ✭✭✭MicktheMan

    As well as checking your ventilation, when you checked in the attic was the insulation running all the way out to the wall plate?

    Also, is the room well heated?

  • Registered Users Posts: 150 ✭✭DamoNolan

    The insulation is old and going to be replaced but as far as I remember it was all the way has an old single panel radiator which is also going to be still heats up well though.

  • Registered Users Posts: 2,386 ✭✭✭olestoepoke

    You should be able to see a decent amount of daylight where the insulation meets the wall plate, if you cant then you need to trim the insulation back.

    Make sure the overflow for the water tank is in good shape and sticker all the way out of the soffit. I'd pull the insulation right back in that spot and get a light and see if the damp is coming from above. And make sure your gutters are clean and functioning the way they should.

  • Advertisement
  • Registered Users Posts: 150 ✭✭DamoNolan

    I didn't see any daylight when I was up there..its away from water tank so its not that..its the old style timber thinking it has something to do with that but I need to check it out further when I get a ladder.

  • Registered Users Posts: 11,188 ✭✭✭✭B.A._Baracus

    Ah mould. My enemy. Ha.

    Place I am in has this too. Something about the area I am in. Even the other neighbours have it. You'll often find its always on a wall that's an exterior wall. Cold getting in to it.

    As you say you will have to investigate further to see what's what. But as for getting rid of mould spots Woodies sell mould spray for about 9ish euro. Works wonders. You spray and give it a few minutes and it wipes off. Wouldn't even know it was originally there. Make sure the room is getting enough fresh air and you can buy a small dehumidifier in Argos for about 60.

    Get into the habit of airing the place out in the mornings. Helps.

  • Registered Users Posts: 33,878 ✭✭✭✭listermint

    I will say with near certainty that this issue is solely down to air coming up your soffit. And then getting underneath the insulation where the insulation meets the wall plate.

    Quick dirty fix for this is to climb in right up as far as you can get and put enough insulation to cover the gap from the ceiling right out past the wall plate. But and importantly leave a gap big enough to fit your hand between the roofing felt and the insulation for the air to be able to come up over the insulation rather than under it to the ceiling as it's currently doing.

    I did a crude drawing of what you want. The red route is where you don't want air to go. If your insulation isn't put to wall plate and with gap above it then you will get red route. You want blue route.

  • Registered Users Posts: 5,367 ✭✭✭JimmyVik

    Its a cold spot. Very common. Put a bit of bleach on a brush and give it a brush every few months. Should sort it.

    And do as listermint says above to check how its becoming a cold spot.

    But the main thing is open your windows often. Because even if you fix this cold spot it will condense on the next coldest spot if the moisture content of the room is too high.

    Another thing that does wonder for this sort of thing is to have a dehumidifier in the house. And if you have rooms that get condensation on the windows leave it on in them for a little while in the mornings. I think everyone in Ireland should have a dehumidifier. Fantastic inventions.

  • Posts: 0 [Deleted User]

    As everyone says and you have got some good answers is a cold patch in the attic that needs more insulation .get a very long screwdriver or coat hanger and downstairs stick it up into the mould and push it all the way into the attic .this can easyily be filled with a pinch of filler later .go into the attic and examine where the screwdriver came up .it's proberly light on insulation.

  • Advertisement
  • Registered Users Posts: 150 ✭✭DamoNolan

    I think this is the problem alright looks the way the attic is.i must get up and fix the insulation further down to passed wall plate but leave a gap for air to pass over insulation..many thanks for drawing 👍🏻

  • Registered Users Posts: 150 ✭✭DamoNolan

    Thanks for all the comments folks some really good points there 👍

  • Registered Users Posts: 757 ✭✭✭C. Eastwood

    DamoNolan. This is either moisture from above the ceiling slab or from below. From above may be caused by ingress of rainwater or condensation off the roofing felt. Because it’s a long very narrow strip and very little discolouration, I don’t think these are the causes - but should be eliminated as a possible cause. It is possibly surface condensation and it may be caused by lack of insulation above this part of the ceiling slab. Because it’s above a window blind rail it may also be something to do with the cold air from the window area because heat loss through the single or double glazed glass will be greater than that of the wall.

    Clean the area with a cloth and a mixture of 1 part household bleach to 3 water.

    To prevent the surface condensation mould from reoccurring, after removing the mould - paint the ceiling with Zinsser Paint in accordance with the manufactures instructions.