If you have a new account but are having problems posting or verifying your account, please email us on [email protected] for help. Thanks :)

MOULD everywhere!

  • 25-05-2022 12:37pm
    Registered Users Posts: 3 lindsay689


    So basically as the title says I have mould everywhere in my house. Me and my fiance are young couple and we have just purchased a detached bungalow. We are trying to understand the root cause of this mould issue and solve it without spending a fortune as we have little to no money. I know our windows need changed as they are mouldy, which I have experience with before and I’m not worried about. The mould I am finding extremely difficult to deal with is a green and black sort of dusty mould. It is everywhere, the floors, climbing our furniture, the skirting boards, in our kitchen cupboards, in our bathroom, in our shelves on the walls it’s even climbing our bedroom furniture and in our wardrobe. Most of the house has lino flooring and there is no underlay between the concrete and the lino I was wondering was this the cause? Though in my hallway and front room it is hardwood floors with lining and the mould is in there too. We do not have any vents in the house so I was also wondering could this be a problem? I open every window in the house daily to try and vent the house myself, but all of the windows in the house are large and therefore I have to close them at night and when I go out. We also purchased a dehumidifier to try and help. I am at my wits end trying to clean the mould and I really can’t keep up with it as I haven't found the source. If a stranger walked into my house they would not see the mould but a lot of my clothes smell musty and I am de-moulding each room so often.

    We have had a plumber in as we were scared there was a leak somewhere but to no avail. I would be so grateful if someone could shed some light on to this problem.



    Post edited by lindsay689 on


  • Registered Users Posts: 18,834 ✭✭✭✭ cnocbui

    As a non expert foreigner, it's my perception that the overall humidity in Ireland is generally very high, which combined with annual low average temp of 10 C, makes mould a near inevitability. Opening windows seems to be the Irish solution, which I have always felt isn't likely to be very helpful, given the outside humidity is usually ideal for mould:

    For mould to grow on a surface it generally needs moisture to be present. This can arise through condensation from the air, so it's likely all surfaces in your house are cold enough on average that moisture is condensing on them. The solutions seem to be to make the surfaces warm enough that condensation doesn't occur and/or reduce the level of humidity in the air.

    Unfortunately, both require energy, in terms of increased heating or running a large capacity de-humidifier. the latter is likely to require far less energy and cost. De-humidifying to below outside ambient levels, like heating, requres some degree of airtightness to the house.

    I have a dehumidifier in my house and that can pull 4-5 litres of water from the air per day. When the external humidity is high, I don't open windows and air, as that just raises the humidity inside. (I am aware that taking in 90% humid air that's 10°C and heating it to 20 will result in a lower humidity) Sorry, I understand the cost of buying and running a de-humidifier may be too much for you, but i don't think there is any low-cost solution.

    Use vinegar to wipe mouldy surfaces as that kills most types, with bleach killing the types vinegar doesn't.

    Post edited by cnocbui on

  • Registered Users Posts: 24 gorse

    Do you live in the west? Mould grows best in warm, moist stagnant air and can grow anytime the relative humidity is above about 60%. Unfortunately, this is the ambient relative humidity in most of the west of Ireland and managing mildew is a never-ending job.

    Is the mould on the windows on the frame, or on the panes itself? If it is on the panes, that is a bad sign condensation, usually caused by indoor humidity being too high, or by fluctuations of temperature (if the house isn't well insulated, the temperature probably drops suddenly when the heating is off). If the mildew is on the frame, are the windows single-glazed or do they have drafts?

    Low cost things you can do:

    Check for airborne sources of moisture: is there a dryer vented into the house, or even just making the air feel damp when it is running? Is there an extraction fan in the kitchen and bathroom? If not, you will have to open a window when, cooking, showering, or drying clothes - or even using a hairdryer. Dry clothes outside whenever possible. Strong sunshine works even better than bleach - if you happen to be doing the washing that one day of summer. 😉

    Open all the windows on warm dry days to air out the house.

    Scrub everything - floors, walls, furniture - with bleach or vinegar. Wash all clothes at 60. Best to do it all in one go, or the spores from one part of the house will just settle in the cleaned part again and grow back.

    Buy a dehumidifier. I use one in the bedroom closet to stop the clothes from mildewing.

    Seal up drafts to try to keep the temperature steady. Buying a thermostat for the heating might also help. (And yes, this is at odds with opening all the windows - it is a pain!)

    Run the heating even when it is not terribly cold. This is not a low-cost solution, but if the house is prone to mildew, it can prevent more damage in the long-run.

    If the mildew comes back after a deep scrub, after all the other measures, there may be damp transferring through the concrete blocks, and you would need to get a professional opinion.

    Also, if the mildew is spreading from contaminated walls, furniture, etc., It will continue to come back. If things can't be washed at 60, or if the mildew doesn't seem to go away with bleach or vinegar, you might have to get rid of some things. Wood and walls can be painted with an oil-based paint after cleaning with bleach, and that usually stops the mould from returning.

    Good luck. It is a thankless chore!

  • Subscribers Posts: 670 ✭✭✭ FlipperThePriest

    Ventilation, ventilation, ventilation. It's written above to open the windows on warm days... yes... BUT also open the windows on cold days. It doesn't matter how cold it is, you need ventilation or you will get condensation and mold issues. You need a longterm background ventilation strategy, not just opening the windows for an hour or 2 a day, that isn't not good enough. Rather than opening windows wide for a few hours a day and then closing in the evening, simply cracking them barely open for 24 hours will do much more for your issue... but by all means open them wide, just don't go closing them then, you need them slightly open in the evenings / all night, particularly rooms that are occupied.

    We moved into a house that smelled fusty the moment we walked in the door, mold on some walls, behind wardrobes etc. There was no vents installed, but good windows with ventilation latches. The only problem was that previous owners didn't ventilate the place. Since we've moved in, we have left a small window on the vent latch in each room 24/7, every season of the year, and kept the place heated in the winter. That's it. No need for dehumidifiers. If you keep air moving about, you will have no issues. There hasn't been a mold problem since. This is a 70s bungalow.

    Either the house you purchased has been left idle for a while, or the previous owner didn't ventilate the place. If you have dry lined walls, there could be all sorts of issues there, with the levels of mold you are describing.

    Btw, above was mentioned vinegar / bleach for cleaning.. yes, but whatever you do, don't mix the two undiluted, it can produce fumes that can be fatal.

  • Registered Users Posts: 3,661 ✭✭✭ EltonJohn69

    mold is very toxic, breathing the spores in can lead to chronic conditions. Wear a n 95 masking when removing and get proper into bold spray. You should throw out what ever it is growing on.

  • Registered Users Posts: 2,716 ✭✭✭ MicktheMan


    when did you buy the house?

    was it occupied or vacant for a time before buying?

    when did you move into the house?

    how is the house heated?

    does it hold its heat well?

    how many in the household?

    when was the house built?

    Working backwards, mould is a living organism and needs moisture to thrive. Unless there are active water leaks or water ingress from outside, this moisture comes from internal moisture producing activities (breathing, cooking, washing etc). This internal moisture needs to be exhausted from the building and if not then there will be a build up of moisture resulting in what you are seeing. Three things govern how efficient the moisture is exhausted; Ventilation, Heating and Moisture load. This is generally a problem seen only during the heating season.

    To tackle this adequately you need to

    1. ventilate properly, little and often is better than large and infrequently. Maybe consider a low energy continually running background centralised whole house extraction system for the wet rooms via the attic space
    2. Use the heating more to maintain a higher internal temperature
    3. Stop breathing inside the house - only kidding. Avoid adding extra moisture such as drying clothes inside, excessive potted plants etc

  • Advertisement
  • Registered Users Posts: 3,010 ✭✭✭ phormium

    Good advice above and just to add there is not usually underlay under lino between it and concrete floor so that's not the problem. My previous lino was glued to floor and my new vinyl tiles are also glued down directly to concrete.

  • Registered Users Posts: 1,627 ✭✭✭ muddle84

    If the house has an open attic and no rooms upstairs it could be relatively easy to fit a MHRV system which would solve your ventilation problem! You're probably still talking about 3 to 4k though

  • Subscribers Posts: 670 ✭✭✭ FlipperThePriest

    This is my plan... when I get around to it. Until them I'm thankful for vent locks on the windows. Depending on the types of window OP you could potentially fit something to give you background ventilation.

  • Registered Users Posts: 34 kc78

    Similar situation here I didn't know who to ask. 70's bungalow with mould in ever room except for the hall. Its mainly on the windows - glass + frame (20yr old double glazed) and the walls beside the windows, there was also an issue with clothes in a wardrobe that is rarely used.

    There are hole in the wall vents in every room. There is an extractor in the bathroom linked to the light switch and the cooker hood extracts outside. Insulation in the attic is patch near the sides, I am getting someone to look at this. Overall the house isn't great at keeping the heat in.

  • Registered Users Posts: 3 lindsay689

    Thank you all for your tips and advice.

    The bungalow was built in the 80s. We moved in a year ago, just two of us living here. We actually know the previous owner as it was my fiance’s grandfather. He was in hospital for about three months before we moved in so it would’ve been idle for that period. He lived in the house for about four years and would have had the fire which is not linked to the heating, and the heating on nearly all day every day as he was elderly. He would not have ventilated the house much though.

    We don’t really know if the mould was there when he lived there, no one noticed it but I feel you would have to live in the house to notice it and he would not of seen it. My windows get a lot of condensation and as I stated previously I am used to mould and condensation on Windows that need replaced. I don’t feel this is particularly the problem. There are vents on the windows that you can open and close, I have started leaving them open all the time. The mould that I am concerned about is mould crawling on all of my furniture. Honestly there is not one piece of furniture in the house that doesn’t have mould on it. I can’t see it on the floors but I presume it is there as it is on all the skirting boards, worse on the exterior walls skirting boards.

    Could this excessive amount of mould on all of my furniture really be connected to the windows needing replaced? The comment about sudden drop in temperature is definitely correct. As we find that the house is quite drafty when the windows are closed and heat is sucked out very fast when the heating is turned off. Again would this cause my whole house to mould? We are very happy to save and try and fix the issue but we do not have enough money to pour into everything that needs fixed and replaced.

    Could anyone recommend someone professional who could advise me? I really don’t know who to go to. We are living in Cork. I am cleaning all of the mould with white vinegar and I am currently painting all of my skirting boards with anti-mould paint. I would really like to find the root cause though.

  • Advertisement
  • Subscribers Posts: 670 ✭✭✭ FlipperThePriest

    Great post and advice above, except I wouldn't bother with dehumidifiers. The house needs to be dried out yes, but unless you have a couple of industrial sized units, the best way to dry it out is with ventilation and heat, which coming into this time of year, should be almost all solar.

    You say you have only just started leaving vents open all the time, so it wouldn't be surprising that you have been having the problem up until this point, no matter how much you've attempted to clean or paint over it... you need to keep vents open all the time from now on. If you clean as diligently as lucalux has pointed out and go back to opening vents for 4 or 5 hours a day in the winter and closing them at night when it gets cold.... the problem will return. If it's too cold in the winter with vents open, and the house doesn't hold heat, that could be a different issue, you may need insulation in attic / walls etc... Closing vents won't solve this.

    Unless you have ventilation 24/7, the fabric of your house will never get the chance to fully dry out as it sounds like it has been absorbing moist air for a long time... it took me a couple of months to remedy a badly ventilated house and fully dry it out, with around the clock ventilation.

    All the above of course assuming you don't have a leak or ingress.

    Post edited by FlipperThePriest on

  • Registered Users Posts: 3,010 ✭✭✭ phormium

    The fact that it's a draughty house you say should have been a help with ventilation I'd have thought!

    Have you been doing anything to contribute to it like drying clothes indoors on clothes horse type thing? It's not a terribly old house, my own is only a few years younger with original windows and I have nothing like that at all, my house is fine and draughty coming from a converted attic which is an advantage in it's own way!

    It's puzzling to have that level of a problem unless it got very bad in the few months it was empty, if that was the cause then it could be a case of get rid of a lot of soft furnishings etc that can't be cleaned successfully. Although couches etc can be professionally cleaned and if you were sure of a bout of fine weather you could put them outside to dry fully.

  • Registered Users Posts: 3,691 ✭✭✭ spaceHopper

    I would go into the attic and check all the edges around the roof, if there are any valleys in roof check internally that there is no leak, it happened in my parents house where it was extended so what is now an internal wall is a double block wall and it was filling with water.

    Buy a cheap damp meter and check all the wall is if one is particularly bad.

    Check the ground outside the house, has clay built up on it to above the level of the CPC and causing a slow trickle of moisture into the house. Check drain pipes for loose joints or for a way for water to get onto the wall. Maybe clean all the gutters. Best done when it's dry as there is less weight and it's a lot cleaner but it's very doable DIY job.

    Is there a damp store in Cork? Could that look at it. How is the house constructed, is cavity wall or cavity block. If it's cavity wall could you get them pumped.

    I'd look at installing room vents, at some point you are going to have to do it anyway, it might as well be now. Get advice on the correct size. If your OH is good at DIY or with a friends help they could probably do it in a weekend. Could you rent an SDS drill and a core bit to cut them cleany and get vent with pipe that slots into the holes with minimal fixing.

    Start sticking money in the credit union and save for new windows...

  • Registered Users Posts: 24 gorse

    Hi Op, I was the one who mentioned the temperature drop. Warm air holds more moisture and if the temperature drops suddenly then you can get condensation on any cold surfaces - windows, cold floors, leather furniture, etc. It is best to keep the temperature stable if possible, but I managed the dampness in a house once by wiping the windows every morning and wringing out the cloth in the sink.

    Your last post sounds like you might have more problems than ambient moisture though. If there is mould on the skirting boards, is there any discolouration to the paint on the walls? How is the drainage outside the house? Does rainwater puddle near the walls? Are any of the gutters leaking? Do you know if a damp barrier was ever installed when the house was constructed? Can you lift a small bit of the lino in an unobtrusive spot to see if there is black mould on the concrete underneath or if concrete feels wet?

    You could Google damp proofing or damp treatment and see if there are any useful guides. If you could find out more about the house, it might help too. Some builders used to mix beach sand in the concrete and the salt ends up transfering moisture through the walls. There are moisture meters and humidity meters, although I wouldn't know much about them myself. Newer dehumidifiers come with inbuilt humidity displays.

  • Registered Users Posts: 751 ✭✭✭ C. Eastwood


    You have a problem of Condensation Mould Growth.

    It’s easy to fix, but can be very expensive.

    A simple way to state your problem is as follows:-

    M - ( I + V) = C

    This is not maths.

    Moisture - (Insulation + Ventilation) = Condensation.

    1. Reduce the Moisture
    2. Add Insulation
    3. Add double glazing
    4. Add ventilation
    5. Heating will also help.

    It was a major problem in the 60’s, 70’s and 80’s, and the SuperSer gas fire was a big culprit.

    The olive green mould growth will trive in areas of lack of ventilation:- behind headboard, behind curtains, in wardrobes. Keep headboards our from the walls. Leave the wardrobes doors open.

    Open windows.

    Its main cause is excess Moisture in the atmosphere. This is caused by Breathing, Washing, drying, cooking, showering and some more.

    If it is very severe, there may be a leaking pipe or many leaks in the plumbing or heating pipes or other pipes encased in the floor. If this is the case then there will be Efflorescent Salts on the walls above the skirting boards, which is pushing the paint off the walls. Let me know.

    You must reduce the Moisture in the house.

    1. Do not dry wet clothes on rads
    2. Do not dry any clothes in the house
    3. Ensure the clothes dryer is exhausting all of the moisture from the clothes out in to the external atmosphere
    4. After a shower or bath, before you leave the bathroom, open the window and close the door of the bathroom on the way out
    5. Fit a good quality Extractor in the bathroom which must exhaust to the external atmosphere.
    6. When cooking, close the doors of the kitchen.
    7. Fit a good quality Extractor to exhaust all the steam from the cooking out of the house.


    Fit as much insulation as you can afford. Insulating the walls will cost approx ball park figure €30,000.

    Must put 200 mm fibreglass in the attic on the ceilings. This will be most helpful. Ballpark €1,500.

    Double glazing will reduce the condensation on the glass internally. €€€. Fit plenty of Trickle Vents on the new windows.


    1. Fit good quality Extractors as advised above.
    2. Get 100 mm dia holes drilled in the external walls about 300 mm below the ceiling in each room. Fit a good open permanent fly grid inside and outside, if it’s a cavity wall you must fit a 100 mm ducting PVC pipe in hole in the wall sealed with mastic, to ensure that dampness from the cavity cannot get in to the house. Approx €150 per room. This is very important.


    See photos below.

    Clean off all the mould.


    Use Zinsser Paint for interior use. (anti- condensation) on Walls and Ceilings.

    See attached Homebond Advice Leaflet below.

    Pages are numbered.

    Let me know your views.

  • Registered Users Posts: 3 lindsay689

    @C. Eastwood

    Thank you so much for your very detailed reply. I think this sounds like my issue. It was difficult for me to understand this on my own as the large amount of mould felt extreme due to ventilation issues. I have never lived in a house where ventilation was such an issue. I definitely have a huge condensation problem on every window (I thought this was due to their age) and on a set of French doors that was only installed a couple (4) of years ago. I thought the doors were installed badly and this was why the condensation was occurring.

    The mould in my house is not a bad as the photos in your attachments, as I said I don't think a stranger would actually notice it but it is there. It would be this bad if I wasn't cleaning constantly. None of my furniture is against any walls but the mould still runs up wiring, my bed frame, my mattress, all of the contents in the bottom drawers etc. I plan on spending a couple of days cleaning everything I own with the fungicidal wash. I have never done the whole house in one go. I will throw out some cheap furniture but I cannot afford to throw out everything. I am hoping if I clean everything and then have a long term ventilation plan to cure my issue.

    I have taken up the Lino and I could not see any mould and it didn't seem damp either. A relation of my fiancé's installed all of the flooring, kitchen and new doors for his father (the owner before us) and I think he covered up the vent in the kitchen. We have two bathrooms and only own has an extractor but we use the dehumidifier in the other. Some windows in the house have a vent like the picture enclosed on the actual glass part of the window, it is mesh and gets a lot of mould. I used to close them at times as they leave a draft in but they still had a huge draft. I now leave them open all of the time. I clean them with bleach but I cannot really get at it with the mesh.

    My garden is very slightly sloped down towards the house so the rain does tend to gather a little at the back. I think I have a clearer idea of some more affordable ways to aid with condensation and I will try to get more drains fitted, and vents in the near future.

    Thank you to everyone who contributed to this and gave me feedback. Everything is helping me.

  • Registered Users Posts: 751 ✭✭✭ C. Eastwood

    Thank you for your kind words Lindsay, you are welcome.

    I fully understand your problem.

    It’s a catch 22, trying to heat the house and provide plenty of ventilation.

    You must keep the Trickle Vents on the windows open permanently, because ventilation is important to reduce the condensation, until you can provide Insulation.

    There is no need to dump any furniture with mould on it. If the furniture is stored in a dry room the mould will die off .

  • Registered Users Posts: 751 ✭✭✭ C. Eastwood


    When you are ventilating the house, an open window in a room with the room door closed will not provide through ventilation.

    Open room windows and internal doors to provide purge ventilation, to remove the damp air from the house. The more often you do this will help to reduce the mould growth.

  • Registered Users Posts: 16,354 ✭✭✭✭ Sleeper12

    I quickly scanned the above posts without reading them all so not sure if it's been asked but are you drying clothes inside the house? Even drying clothes on a clothes rack/horse can cause your issues but worse if driving clothes on rads.

  • Advertisement