Mould in houses: Causes and solutions

By The Helpful Engineer / On / In Existing Building Issues

It’s that time of the year again when the days are getting shorter and colder and that means that your house is more susceptible to mould growth. Mould growth is caused by either building defects, which wets building elements, or by condensation. Mould growth will develop on walls, furnishing, and clothes once dampness is present for a period of time. Mould fungus needs three conditions to grow (infection, nourishment and a damp environment) and these will be present in a dwelling once a damp environment is established for a period of time. It is considered by some that the presence of mould within buildings can contribute to serious health risks. Toxic moulds can cause a range of symptoms including headaches and a wide range of skin lesions and rashes. The areas where mould is located need to be treated using a suitable fungicidal wash. But this is a temporary cosmetic solution and the cause of the appearance of the mould, the damp environment, needs to be dealt with prior to redecorating. A damp environment can also cause rot in timber and we will cover that in a later post.

Condensation occurs when warm moist air meets a cold surface. Its more likely to occur in winter because the building surfaces are cold and because windows are opened less, thus trapping the moist air.

Condensation is caused by a combination of:

-Poor ventilation.

-Unheated and poorly insulated rooms.

-Excessive moisture in the air, i.e. from gas heaters, drying clothes indoors etc

– Excessive moisture on the building element itself because of defects in the building and/or flashings.

SOLUTIONS:

A. Mould remedial action necessary, based on building use

  1. Maintain reasonable background heat levels in the property. If a room is allowed to cool the door into it should remain closed to prevent warm damp air entering from the remainder of the dwelling, and condensing in the room.
  2. Limit the drying of clothes internally and if clothes are dried inside they should be dried in well-ventilated rooms (with windows open) and with the doors closed to other parts of the dwelling.
  3. Limit the use of movable gas heaters, as this type of appliance releases large amounts of water vapour into the air, if they are used an external window should be left ajar in the room to allow fresh air to enter and the moisture produced to escape quickly.
  4. After using the bath the windows should be kept open/ or extract fan on and the door closed until all the moist  air is removed.

B. Mould remedial action, based on building defects

  1. Remove mould from all surfaces where present by washing the surface with a suitable fungicidal solution and allow it to drying. A dehumidifier can be used to aid the drying. Do not attempt to brush the mould off the walls, as this will just spread it.
  2. Increase ventilation to rooms.
  3. Engage a specialist to inspect roofs, walls, balconies etc for leaks in water proofing membrane and flashings. Perhaps a DPC (damp proof course) or DPM (damp proof membrane) is missing or damaged. Bear in mind that water entering a leak can penetrate in one place, track along a surface and exit in a remote spot.
  4. Provide additional insulation to avoid cold spots on walls, floors and ceilings.
  5. Provide a mechanical extract fan to ‘wet’ rooms i.e. bathroom.
  6. Finally, the building should be regularly maintained by:
    • Checking, maintaining and clearing gutters, drains, gullies and downpipes.
    • Removing weed and plant growth from the building facades.
    • Carrying out regular inspections and repairing any damage to downpipes, roofs and gutters promptly.

115 thoughts on “Mould in houses: Causes and solutions

      1. Hi I am renting a property and I have just got an excellent
        external wall insulation job but on carrying out a detailed inspection of the property we discovered mould in the main bedroom and bathroom which has an extractor fan in it.
        The tenants did not tell us about the problem
        Will the installed outside wall insulaton resolve the problem

        Colin

  1. Hi there,
    You mention “Engage a specialist to inspect roofs, walls, balconies etc for leaks in water proofing membrane and flashings. Perhaps a DPC (damp proof course) or DPM (damp proof membrane) is missing or damaged.”
    Do you have any contact information as to who can do this, phone number would be appreciated, I live in midlands, thanks.

      1. I would also like a number if possible ( i know this is dragging up an old post, but your site was no2 on the list when i googled)
        thanks.

        1. I am currently looking for a ‘specialist’ to help us identify the cause of a musty smell in a number of rooms in our house and mildew in one wardrobe. Problem is, I don’t know what I am looking for – an engineer of some sort maybe? I am in Munster. Thanks!

  2. hi im looking to find a specalist for damp proofing my home. if you have a contact number it would be great

    thanks
    ben

  3. Hi,
    You mention “Engage a specialist to inspect roofs, walls, balconies etc for leaks in water proofing membrane and flashings. Perhaps a DPC (damp proof course) or DPM (damp proof membrane) is missing or damaged.”
    Do you have any contact information for someone who could do this for a block of units on the Sunshine Coast? A phone number would be appreciated. Thanks.

  4. hi there, i have a white powder like mould on my walls, what is it and what causes it , and how do i get rid of it

    thanks

    1. There is not much information to go on. But if the powder is dryish and not mould like, it sounds like the wall is wet and the natural salts in the interior of the wall are being brought to the surface. When the damp evaporates, the salts come out of solution and are left behind on the wall. This being the case, the defect that is causing the wall to be damp need to be fixed.

      The white salts, if thats what it is, should not be washed off the face of the wall as the water will cause some of it to be dissolved and reabsorbed by the wall, to later come to the surface again. A dry stiff brush could be used instead. There are products available to dissolve the salts also to aid removal but you would need to talk to your local hardware store about any particular product. The main point to remember is to stop the water entering the wall.

      Hope that helps.

  5. HI,
    WE BOUGHT A HOUSE WHICH WE HAV RENOVATED PUTTING EXTERNAL INSULATION,ATTIC INSULATION ETC.WE HAVE A SUSPENDED WOODEN FLOORS WHICH ARE NOT INSULATED AND DOUBLE GLAZED WINDOWS WHICH ARE ALIMINIUM AND CONDENSATE AT NIGHT TIME.WE HAVE NOTICED IN ONE ROOM AT SKIRTING LEVEL, PATCHES OF MOULD.ALSO WE NOTICED A SMELL IN THIS ROOM.WHAT DO YOU THINK COULD BE THE PROBLEM?WE HAVE A 60MM VENT IN THE WALL WHICH IS OPENED ALWAYS.YOUR ADVISE WOULD BE GREATLY APPRECIATED.REGARDS NIALL

    1. Niall,

      Without any further details that sounds to me like rising damp. Rising damp can be caused by a lack of a DPM or damaged DPM. A damp proof course is a barrier installed at the base of the wall when it is being built to prevent dampness from the ground rising by capillary action within the wall. Or perhaps a DPC has been installed but the ground level has been raised above it outside, thus allowing water to enter at the base of the wall. Some questions for you. Is the house old? Is the wall solid or does it have a cavity? Are there any other defects in the area like leaking gutters, leaking downpipes, cracked render that may have an impact? See e-mail address in contact me section of website if you want to contact me directly.

  6. My neighbours gutter was leaking for months, this caused the rain water to run down the exterior water and into the air vent in our bedroom. They eventually got the problem fixed, but we have mould on the wall in the room and the wall feels damp. Do you think this has caused damage and what is the solution – Damp proof inside and out ?? The downstairs room is okay.
    Thanks

    1. It’s very hard to say without seeing it. But if it was my house I would do the following:

      1. Treat the mould with an anti-mould wash, shop bought or made up with warm water and a little bleach. Use gloves and take care none falls on carpet/ clothes etc.
      2. Wash off wall and allow the surface to dry.
      3. Then use a dehumidifier, from a hire-shop if needs be, to dry out the wall. Follow the instructions on using the dehumidifier, close windows and doors, cover vents etc. You will know when the wall is dry as there will be no more water being removed by the dehumidifier. I wouldn’t use the room while the dehumidifier is in action, just go in on a regular basis to empty the water.

      Bear in mind the other points in the article as well, i.e. don’t dry clothes in the room, ensure the room is warm etc.

      I hope that helps. Let me know how you get on.

      1. You mention ‘specialist’ to report on damp proofing etc would you have a contact person in the Cork City area please/

        Best Margaret

  7. Hi I live in a house apprx ten years old. I have been in it almost two years. Before that it had been only rented for one year, the rest of the time lying empty. During the summer I noticed a smell in one bedroom. I found that in the built in wardrobe (floor in wardrobe is same as the floor in the rest of the room – parquay wooden floor, would not be great quality) shoes and clothes had mould over them so I moved them out. It is now in another bed room. I think the problem may be coming up through the floor – could this be possible. What could I do to sort this problem out? I live in the north west.

    1. Hi Clare. Its hard to comment on limited information. If you could email me a few photographs and add a few more details like is it happening on the ground floor? are there any vents in the room? etc. I will then let you know what I think.

  8. can you advise. Party wall in bedroom has marks on it like fat splashes. I have pulled out 5 drawer chest and dressing table and the wall where it has had brown fluff opr dust on it has now got marks in places. I have felt the wall and it feels quite dry. I have hovered as best I can but don`t know what to do. Is it a fungus or is it because I have not left enough room for the wall to breath?

    Regards,

    Ros

    1. Hi Ros,

      Not 100 % sure what it is. I came across something similar once and it was caused by penetrating damp in a solid brick wall. The flat roof above was leaking for a long time. But in that case the areas of fluff (fungus) were large. If you could e-mail me directly with some pictures and a description of the house construction and age I would be interested.

  9. Living in north sligo. House is 4 years old & theres damp mould on one ensuite door & on wooden set of drawers in ensuite. Ensuite is on ground floor at gabel end of house. I noticed a fine crack on outside gabel end from ground to roof. Theres no air vents or extractor fan fitted in ensuite. It’s a rented house. Is the crack outside on gabel end the cause of the mould? I keep the ensuite very well vented when the shower or sink is being used.

  10. Hi, I have a rental house in the north east, can you recommend contact information for someone who could assess mould damage & fixes for me? There is mould in the upstairs bathroom, the wall over the sink is badly mould damaged. Several weeks ago, we cleaned out the gutters and re-pointed parts of the roof, where we thought there may be leaks – we then cleaned the wall over the sink but it has since returned just as bad. I need to fix this issue once and for all. Appreciate any help – Mike

    1. have dry green powdery stuff on back of furniture and bedroom doors,what could b causing this and best way to get rid of it plz

  11. Hi helpful eng
    I built a house 5. Years ago its a story and half dormer and I have noticed mold in our bedroom up stairs above the window
    We have a ensuite shower the house is well insulated .the window is the story and a half part of the house
    Thanks for any help

    1. Hi Adrian,

      Its hard to say without seeing it in person but it sounds like it could be a cold bridging issue, i.e. where the wall insulation is missing or settled. I think the best course of action is for you to contact the original Builder and the Engineer/ Architect to visit and investigate it for you. They will be familiar with the design and construction details.

  12. Hi,
    We moved to a new house in May, the house was built in 1998. We have just noticed that our mattresses on the beds are covered in Mould on the underside, the washing basket is also covered in mould, as are a few items of clothing. It is not a particularly damp house, although there are no ventilation bricks in any of the rooms, and the house is built into a hill, so half of it is effectively underground, but not one of the rooms with a mouldy mattress! Can you recommend what we can do to get rid of the Mould or what may have caused it?
    Many Thanks
    Becky

    1. Hi Becky,

      That doesn’t sound good. Sounds like a lack of ventilation in your home, but I think you need to contact a local architect/ engineer to investigate the problem and detail solutions.

  13. Have problem with semi detached house on estate 15 years old dampness on wall of back room next to patio door. Mainly on wall which is attached to neighbours house. Possibly connected to house extension on adjoining house. Would appreciate if you could email me directly to provide advice on having it investigated. Thanks

  14. Hello,
    We are currently experiencing a problem with mould in a number of rooms in our house. Items in the house are getting mouldy (e.g. clothes in wardrobes)and there is a patch of mould in one of the bedroom walls (in a top corner of the wall). In the winter mornings there is a lot of condensation on the windows. Also there is little, if any, heat retention in the house after the heating is turned off.
    We make a point of not drying clothes in the house. The vents in the bedrooms are always left open. The house is heated on a regular basis, and also aired regularly. Both the bathroom and the ensuite have extractors installed in them.
    While the mould on the wall has not worsened, the spread of mould has in the last few months. Who exactly would be qualified to offer impartial advice? Is drylining the only solution? We feel with the measures we have taken that the mould should not be developing any further, do we need to use an anti mould wash?

    Any help would be greatly appreciated,

    Regards,

    William.

    1. Hi William,

      An anti mould wash is only a short term solution to the problem. From what you have detailed it would seem that improving the insulation to the walls (and possibly the ceiling/ roof) is the long term answer. You could dry line it internally, install external insulation or if the walls are cavity construction pumped insulation is probably the cheapest and easiest solution.

      IF you require impartial advice, you can contact any one of a range of building experts: chartered engineer, architect or building surveyor. Any of these will survey your dwelling and issue you with a report detailing the problems and recommending costed solutions.

  15. Hi,
    I got a large shed built in my back garden just for storage.Its up about 6 years and my daughter now wants it as a play room so i got insulation boards put up, got it plastered and painted. Over the years i thought i noticed the brick work and one of the ceiling beams slightly wet. The shed has never had any heat go into it so i now have two small heaters to try and heat it up.I have now noticed on two of the walls black mould/mildew and its starting to spread across the walls.Could you let me know what you think could be causing this and what i could do about it.

    Thanks
    Michelle

  16. Hello,

    We have a problem with mould in one of the bedrooms of our rented property. It is a white fluffy mould and also darkish mould that covers an exterior wall. The house has very poor insulation and i fear the mould is being caused by body heat when lying in bed. The estate agents are trying to palm us off and say it is condensation and so our problem with regards to ventilation. However, we open windows during the day and have the heating on for a long period so we are doing all that we can do but we cannot heat the house sufficiently due to bad insulation. Does this sound like it is caused by bad insulation or a different problem?

    Thank You!

  17. Hi, we have an old build attached to our home( approx 80 yrs old), just recently i was in one of the old bedrooms and noticed white fluffy mould. When i pulled back the bed i realised the floor had completely fallen. The Joices are rotten. I am concerned as we have heating in the room but probably not ventilated . My two questions are 1. Is there a danger in mould like this ie breathing in while cleaning. 2. Who would be the right tradesman to call for this in particular would it be a structural engineer ??.

    Thanks in advance

    1. Hi Hayley,

      Sorry to hear about your difficulties. It would be normal for a house owner to clean up small areas of mould on wall/ ceiling surfaces with little difficulty. Usually buying a damp removal products and taking the precautions detailed. But in your case, which sounds quite serious, or where mould is located in concealed areas it would be important to get a good damp specialist company in to investigate, clean and treat the affected areas. If it is not done right the mould will come back. You will then need advice then from an engineer about replacing floor joists etc.

      Hope that helps,

      Regards

  18. Hi,

    Impressed with the advise given on here

    Looking for some advise myself. I have a ground floor apartment. There is a balcony above the 2 bedrooms. I have had damp in the past in the 2 bedrooms, nowhere else in the apartment. Got a couple of companies out to inspect. One suggested drylining. From talking to people and googling I belive this is not the correct solution (I have heard of someone in the same estate getting it done and the problem came back worse than ever)

    I got a new ventilation system into the whole apartment – and vents above every door. I do think this has increased the air quality of the apartment (might be my imagination) but 6 months later I am getting a musty smell from the wardrobe and drawers!

    Do you have any suggestions? One suggestion from a neighbour was that the rainwater is seeping through the balcony slabs as when you lift one up, apparently you can see a lot of sitting rainwater. He said that he got the builder to fix the balcony and the work included putting a ‘slope’ and a new drain pipe under the balcony, so that the rainwater would not be sitting underneath the slabs. HE reckons this solved all problems for him.

    I’m not sure if I am 100% convinced Do you think this would be a realistic solution? (unfortunately the homebond term is up for me now so I am unable to get the same builder in).

    Would be grateful of your thoughts or advise as I do not want to spend anymore money on it unless I can be guaranteed it will sort out my problems (I spent a good bit on the new ventilation!!)

  19. Hi. We moved into a newly built house end June 2012. Our bedroom is over a car port and is noticeably cooler than the rest of the house. No heat from below maybe why?

    Our bedroom has built in wardrobes on the outside wall and I’ve noticed mildew in the bottom corner and on my shoes (on the floor in there).

    What could be the cause?

    1. Hi Julia,

      Typically the ceiling over a car port within a house is a reinforced concrete slab. This helps to slow the spread of fire, as one involving a car would typically be more fierce. From what you have detailed it sounds like the ceiling to the carport (or the floor of the room over) is not insulated. My guess would be that the carport is not heated and is not well insulated. Therefore the ceiling needs to be insulated to prevent the heat from the room above being lost to the cold carport.

      Regarding your wardrobe, it sounds like your external walls are poorly insulated, which will need to be addressed. Also your wardrobes should have vent holes to allow the warm air in the room to enter and warm the interior of the wardrobe.

      Regards,

  20. We have mould behind our chest of draws we have washed it off with a fungal wash, but cant understand where it’s come from its nowhere else in the bedroom . It’s black and seems to around the skirting board and about 3 to 4 inches above. Can’t stand the thought of it, please help Sheila

  21. Hi. I became unemployed around two years ago and have living in a damp mould infested bedsit since. I have tired to do all I can to get rid of it. Washing the walls with anti mould solution and painting with perma white a special kind of paint for keeping mould away but all to no avail it keeps coming back so much so that now I have developed severe sinusitis and ashma. What are my legal options as in sueing the landlord. Anyone who has gotten sinustis will know its scarey to say the least its like episodes of fever you start shaking become dellusional your. I’m serious. I lose the control of my body two or three times a day and at least twice at night. The mould has really infected me. I have been to the doctor and he says I badly need to get out of there. This infection and remember its a household mould infection can be deadly .

    1. John,

      I wouldn’t be able to advise you legally, but you should bring the issue to the attention of your landlord, if you haven’t already. The article above provides should information to help find the source of the problem, but if its as serious as you say an engineer or architect (fully trained and with PI) should be engaged to carry out an inspection and report on suitable remedies.

      Regards,

      T.H.E

  22. Hi,
    We are in the process of buying a house that we have noticed has a small patch of damp in the corner of one of the bedrooms. On the outside wall where this bedroom is, there is a timber car port that looks like it is on it’s last legs. Also this bedroom has a very old double glazed window that will be replaced. The damp we noticed is along the bottom of the wall in the right hand side corner. Does it sound to you as if the damp is coming from one of these problems?
    Thanks

    1. Rachel,

      As you are buying the house I would first recommend that you get a full structural survey carried out to protect yourself. There seem to be a number of issues which should be fully investigates. The engineer carrying out the survey will advise as to the cause of the problems and recommend solutions.

      Best of luck,

      Regards

      THE

  23. Hi

    We have, what I think, White mould growing on the internal Walls of our garden brick shed. Our shed is north facing so the rooms get very cold. It’s single brick built with tiled pitched roof. The internal rooms of the shed have been insulated with a foam plaster backed and then skimmed and painted. We have already treated thie affected area by chipping og the plaster, taking of the angle bead and skimming it. After skimming we treated the area with anti fungicide solution and let it dry. After few days we painted the area but the mould has appeared again. Not sure if we are doing it right. You mentioned in your advice that the area needs to be seen by a specialist. Please can you pass me the details by email.

    Looking forward to hearing back from you with a solution to fix this ongoing problem.

    Thanks and regards

    Varsha

    1. Hi Varsha,

      From reading your previous e-mail, it is hard to say without seeing it but my guess would be that it seems like water may be penetrating the wall surface from the outside. I think this because you mentioned the wall was single brick leaf and this type of wall would be prone to it.
      This assumes that the insulation you have installed is adequate, that there is a DPC in the wall and that you have investigated the causes of mould formation discussed in the article above.

      Regarding someone in your area, please PM me saying where you live.

      I hope that helps. Regards,

      THE

  24. Thank you so much. We are a bit confused with some builders saying that it is salt leaving the bricks and some say it is damp. I live in south Ruislip, middlesex

  25. Hi, These are the best, and most sensible tips I’ve found, thanks.

    Our first floor maisonette has an old single brick balcony off the kitchen that has since been closed in (mostly with glazing). This adds much needed space to our tiny kitchen, but because it’s single brick it gets condensation and mould growth. We have a dehumidifier in the balcony area, and make sure we don’t push things up against the single brick wall in winter. This solves the problem, but it doesn’t let us utilise the space very well – we’d love to have units fitted around this area to extend the useable space in our kitchen.

    I imagine, from your suggestions we should “provide additional insulation to avoid cold spots on walls” before re-doing our kitchen.
    Do you have any thoughts on the sort of tradesperson we should contact, and / or the sort of insulation we should choose. People (not experts) have said that the polystyrene linings will not provide enough insulation, and someone has recently suggested insulating from the outside which seems an interesting idea. Others have suggested that nothing will fix the problem and we won’t ever be able to put things up against the single brick wall in winter…
    Any thoughts would be much appreciated. Many thanks,
    Debs

    1. Hi Debra,

      From what you have said it would seem that external insulation might be the best solution for you. It would mean that the internal space is not reduced and could be installed without to much disruption to your house. It would require a waterproof render over it off course.

      Regarding the use (or not) of polystyrene: this is a cheaper slighter and less effective insulting foam, but if you want to use it you could thicken the depth used. There are other more effective foams (polyeurethane, isocyanurate etc), but they are more expensive. You should probably engage an architect or engineer to look at your property in person and advise of the best solution.

      Regards,

      The Helpful Engineer

      1. Thanks for the advice! Now to see if the Freeholder is OK with us making changes to the exterior of the property… I imagine my neighbours have the same problem, so I can’t imagine they will have a problem with it – we’ll probably be the guinea pigs for the whole street!

  26. Hi we have a dorma house built in the 70s. We had cavity wall insulation done about three years ago and over the past two years in the little bedroom at the front that has two outside walls there is a lot of black spotty mould and the wall and room feel cold. I’ve cleaned it off but his build in wardrobe smells damp too. Please could you give some advice as to what it could be, is it just lack of air into the room. We were thinking of replacing the plaster board under the window with an insulated plaster board and insulating the dorma behind, would this work or make the situation worse. If you could email me back that would be brill. Thanks x

    1. Hi Angie,

      Its hard to say. Presuming the cavity wall insulation was done correctly (did you consider whether they missed a spot?) is there sufficient insulation in the attic above the room? Have you checked to make sure that there are no leaking pipes internally or is there water getting in from some source like overflowing gutters, roof leaks or cracks in the wall. Once you have eliminated all these possibilities it is a question of making sure the room is well ventilated and adequately heated.

      Let me know how you get on.

      Regards,

      THE

      1. Hi
        I have a detached bungalow built in the late 60’s, I had cavity wall insulation put in not long after I moved in 12 years ago. I started to notice black mold in the lounge outside wall and the bedroom outside wall, it’s just above the skirting boards. I did get the structural engineer back thinking that it might be that the cavity wall insulation had been wrongly injected, he said that the damp meter was reading normal and that in the lounge it was that there was only one layer of board under the window which covers the whole of that wall and the coldness from outside hitting the warmth of the radiator was causing condensation, and suggested that I get some insulating paper on that wall and also to use a dehumidifier. In the bedroom he said it was a lack of ventilation and again the dehumidifier should help. In the bedroom I get a musty smell on clothes that are in the bottom drawer. I am in the process of decorating the bedroom and I have had the wall skimmed, however on the wall that had the black mold the plaster has dried all mottled from below window height and in places the plaster has pitted. The plaster has never seen this problem and has lightly skimmed over the pitted areas. I am concerned that I am going to get mold back. I have had a larger window put in to aid ventilation.
        I would really appreciate your comments, thank you.

  27. Our semi-detached house is 20 yrs old. We have severe condensation on windows, especially patio door off kitchen and bedroom windows. Side kitchen door (teak) has no condenstaion. Could the windows be faulty? Skirting boards and window sill have black mould. Charles

  28. Great post, thanks for sharing! Dry Rot is also a big issue along with mould and damp! Dry rot is a major building decay fungus and is one of the most insidious and destructive problems your property can have. It often causes extensive and very costly damage as it spreads from area to area looking for its food source, timber.

  29. hi there we have a major mould problem in our rented house we have treated it so many times and it keeps returning we think its coming from underneath the floor boards and we were told it is not insulated as the floor boards are starting to peel i was just wondering how much would it cost in ireland to get a engineer in to take a look to see what is causing it as we got onto our landlord so many times about it and nothing has been done we have 3 young kids who get sick alot thanks

  30. Hi, please help? I have a light dusty mould getting in to fabric and wood in my bedroom on the gable end of my house. I have blown insulation in to the cavity and lined the walls with polystyrene type wall lining and insulated above the room in the loft which has reduced the problem. I still get the problem all be it reduced now. I have a louvre vent and vented windows that I can open and shut. What advice would you give to get rid completely?

  31. Hi, thanks for this helpful post. I currently have a mould issue due to a leak from the roof in my apartments. I am ground floor and it ruined the two flats above and has caused a wall to become damp and mould spots on the wall and ceiling. I have received a quote from a friend who is a dry liner and here is the work he prescribed:

    1) Removal of any defective wall, ceiling plaster
    2) Make good any imperfections with waterproof sand cement render
    3)Treat mould areas with anti sulphate solution, Dulux weathersield multi surface fungicidal wash
    4) Seal background with water tight plaster sealer
    5) Re plaster (skim) walls & ceilings

    My question is firstly would a dry liner be a suitable person to treat this kind of situation and if so do you believe this work is what would be expected. A tenant has just left the property so I also intend to air the property a lot more and I have purchased a de-humidifier.

    Thanks for any help.

    James

  32. Hi there,

    Some great info being shared here! Would appreciate any help on my issue. The house I live in is 7 years old and for the last 3/4 years mold has been appearing in the corners of all upstairs bedrooms starting closest to the ceiling. Nothing has appeared in the hall. attic is insulated and there is polystyrene in the wall cavities. I do notice condensation on the windows in the morning also. Is this simply a case where more insulation is required or is this more serious?

    Appreciate any help you can give me!
    Frustrated home owner,
    Laura.

  33. Hi, I would really appreciate your input. We have mould on alot of items in a walk in wardrobe, a small area of paint bubbling on one wall about half way up and mould on the other side of that wall in another bedroom. No water pipes in the area we have been told. There is a large pipe in the corner of the room (we think this is a radon pipe) running from ground up into attic and vented out. The wall (not solid) around the pipe is water damaged but it looks like the moisture is travelling down from the attic to half way down wall. Is the moisture coming from the pipe?. Where this pipe enters the attic above this room we found some insulation around it was very wet. any advice greatly appreciated, thanks.

  34. Hi there I’ve been getting mould in my bed room. It starts in the corner on the gable end then begins to creep along the wall. It sits on the paint and spreads quik once it starts. If I scrape it of the wall tho the plaster is still clean and dry. Any ideas thanks

  35. Recently renovated an old house, took everything out – floors, walls etc. but I have just noticed that in the downstairs study & newly laid laminate floor appears to have green mold on it in the corner. The water has just been connected & it has only appeared, there doesn’t appear to be any buckling of the boards & the room hasn’t been ventialted as the handle was missing on the window, but it appears to be where the boards meet – any ideas?

  36. Hi Helpful Engg., is it possible to get rid of mold/fungus by Air fumigation like the one done for a Surgeons Operation theatre ? – what would be the most effective way to eliminate mold or fungus ? Thanks in advance

  37. I just bought a place in south Florida and I find a mist of water on the laminate floor in one corner of are bedroom under a shelf and near a cabinet. They had damp ride there when I moved in but really didn’t pay much attention to it. It just appears like a dew from outside. Could this be from the a/c ?

  38. Hello I moved into an apartment that has 2 bedrooms . The last tennants got an air vent put into each room with a white cover over it. My 1 year old son is in one of the rooms. The window and French doors has usuall damp but easy wiped . Coming into winter can feel rooms getting little colder at nites . I am wondering am I able to cover the vents at nite and open during the day or what would be the best solution ? Please and thank you Steven

  39. Please help….I moved into a 1970’s bungalow last year, the previous owner of 12 years used it as a holiday home and never used it during winter. We renovated it by replacing all single glaze with double glazing and we got the walls pumped with insulation and the attic insulated. However I am having problem in the bedrooms only. They have mould growing on the outside walls in the top corners of the rooms and on the underneath of top of where window meets the wall(where blind hangs ). I washed off the mould using shop bought mould and mildew remover which did the job temporarily, however one room in particular seems to get it worse than the others and recently whilst clearing out a chest of drawers which lies near the outside wall of this bedroom I noticed a wicker basket that I have on top of the chest of drawers had mould growing on it on the side closest to the outside wall of the room, as I have young children I am very concerned about this as a potential health hazard. This room is north facing too so gets no sunlight or heat during fine days (however my sitting room, with stove, is north facing too and has no mould issues) This bedroom never had a wall vent and when we replaced all the windows we would have blocked up all other room vents as we got vents installed within the window frames instead. I was told by our builder during renovations that there is a solid concrete beam running around the whole rim of the house whether this has any bearing I dont know. If it was a case of just once a year cleaning off the mould on the walls then thats ok but when mould appears on items of furniture near the walls then I wondered was there a bigger issue?
    Would a dehumidifier help? is it a case of 12 years of unused house dampness that will dry out eventually? should I install a wall vent aswell as having the window vent? Would this concrete beam be the problem and would installing insulted slabbing to the internal bedroom walls on the external side of the house solve my problem? Apologies for all the questions but I’m at my wits ends trying to solve this problem, and as I have a newborn baby who will be moving into one of these bedrooms in the coming months I am eager to get it solved ASAP, any help is appreciated

  40. Thanks for clear advice. But I wonder could you give me name of a specialist for galway city area. Much appreciated.

  41. Hi there,

    we have just moved into a rented massionette, when we moved in, all the walls looked fine and no mould, we have only lived here a month and we have mould. The bedroom that has the mould is an extension to the house (was once a big house, converted to two massionettes) the bedroom is alot colder than the rest of the house, but we have the heating on to try and keep it warm (currently about 20C) We have quite a lot of mould on one wall, seems to go across the wall in patches and also up two corners of the wall. The mould looks like patches of green bobly and some yellow/white bobly patches. There is also the smell of mould. We always open windows while having showers and dont dry clothes in the house, there is also a air vent in the wall of the bedroom, house was probably built in the 1920, not sure about the extension though.
    Do u have any idea what sort of mould this could be and how to fix it? We have two kids and one has asthma and are worried about him breathing it in. We also have had a dehumidifier on during the day for the last couple of weeks and hasnt improved, just got worse. we are not sure if we noticed it get worse since we have had some really wet days of rain.

  42. please can u advise what to do about mould on clothes and shoes in my wardrobe? We also have mould all over the walls in our lounge and leather sofa?? We live in house approx 10 years olds. Also both rooms are well ventilated and heated?
    Regards
    Sarah Bryans

  43. Hi

    I live in a terraced house and the wall in the hallway between myself and the neighbour appears to have a dust like substance on it which wipes off by hand. This wall has always been cold. The bathroom is also against this wall, no extractor fan! Could this be the problem? A builder looked at it but could not explain it.

    thanks in advance.

  44. Hi,

    Last year in the bathroom and bedrooms we noticed there is a balck residue which can be wiped away. As winter went on the size of the residue got bigger. We have treated this with a fungal treatment, but the problem has started again.

    The outside of the property has wooden faschia’s could this be the root cause? The house was previously owned by family, and this has just started. Could it be consendation?

    Could you please advise.

  45. Hi, we moved in to our house in September.
    It is semi detached circa 1970. We had built in wardrobes fitted in the master bedroom 6 weeks ago.
    Just a few days ago I discovered items of clothing, particularly jackets covered with white/green fluffy mould. It was also on the inside house wall of the wardrobe which is at the front of the house.
    I then noticed it also in the other side of the same wardrobe that sits closer to the centre of the house. (This is on the party wall with the adjoining property) the wardrobe is very cold inside.
    We have also discovered mould on the inside of a free standing wardrobe in our daughters room on the other side of the house and on the clothes inside.
    We have extractors in the bathroom, we open windows regularly and have our heating on.
    We seem to get a lot of condensation on our windows as well.
    We contacted the previous owners who are friends , they are shocked as they have never had this problem.

    Would a dehumidifier help us? Or is there anything else you can suggest?
    Please help us with any advice.
    Thank you.

  46. After some advice if possible..
    I currently let out a victorian terraced house and have found some rising damp at the front which i am getting sorted with some damp proofing, but also i noticed some mould on the walls in the back bedroom upstairs and bathroom which is next door to it. This bedroom is usually quite chilly and has two external walls and the bathroom is quite small with a small window. Would I be right in thinking this could be solved with a vent fan in the bathroom and maybe some wall insulation in the bedroom? I had a company come and look and their solution is a rencom ventilation system i believe its called. Would this be a better idea? I didnt know whether this was the best idea as i have mixed reviews and have never had a problem with mould before in the ten years ive owned the property so im looking for any help/advice you can give asap. Gutters and roof were all checked about 6 months ago also.
    Many thanks

  47. Hi,

    I have just stumbled upon this article as this weekend we noticed that shoes in our wardrobes had some mold on and a couple of clothing items in the wardrobe next to the exterior wall also had some, we know our drains need clearing and also the window under the wardrobe has loose guttering, meaning water runs down the exterior wall, could it be these factors causing the mold issue? or could it be partially damp clothing? we also get spots of mold round our bedroom windows despite the heating being on as we get varying amounts of condensation. There are no damp patches on the walls or ceiling and this issues is isolated to this area.
    Another thing i have noticed is in a corner behind my washing machine there is also mold (where the water pipes are, could this be a leak? there is no mention of damp in that area in our homebuyers report so must be since we moved in

  48. Hi just wanted to ask I live in an apartment the bedroom is very cold even when heating has been on , it has no windows just a large door , gets really bad condensation causing mould all over door but has started getting mould on the walls over the door and separated wall beside my bed the building is only 5 years old and has bad mould all up the stairs too , it has a flat roof on it which 2 years ago has had work done on it to stop this but the building has not been treated , maintance man has said it just there no ventalation , should it still be growing on the walls , and I have a child that is a chronic asmatic and this seems to be affecting her really bad even when cleaning, I have bought a dehumidifier and it is pulling 10+ litres of water out a day he told me to just keep cleaning it off the walls is this right

  49. I have a house which is rented, the tenants I have in have a problem with damp in a bedroom (which has2outside walls ) and condensation on double glazed windows all upstairs. I installed window vents earlier this year to help create movement of the air around also suggested they turn up the temperature for the central heating . After no problems during the summer now the cold weather is back the problems have reappeared with green mould appearing on shoes and back of wardrobe.
    The loft is well insulated and the house is in good order ( it is a timber house ) could you please advise me of anything I can do, either best to call a specialist or a simple remedy we live in the north of Scotland !!!

  50. Hi I have an ground floor apartment which I had rented out for a year. I am moving back now but the place is destroyed with mould and the smell of dampness I can’t seem to get rid of it. I have a unit in the sitting room and I washed the green mould all off it, but the smell is disgusting dampness seems to have gotten into the wood and I can’t get rid of it, if anyone one has any tips they wood be much appreciated or else I’ll have to throw it out and it is a very expensive piece of furniture. I have scrubbed the place to try get rid of the smell. Thanks in advance.

  51. Hi we moved into our house 3 years ago. It was fairly unloved. Built in 1907. We have double glazed and done extensive decoration. We have the usual black mould issues in the bathroom but in recent months are getting green powdery type mould inside cupboards, on walls etc. It seems fairly fast growing and we have now found it in 4 different upstairs and downstairs rooms. It is always on outside walls and places where air movement is poor. We don’t know where to start to fix the problem. Any suggestions? We live in Worcestershire. Thanks.

  52. Hi this weekend I went into a storage cupboard just inside the door of my apartment and just before the bathroom to get to my electrical mains box. I discoverted some very blackmould on the ceiling down one side of the wall. looks like its coming from ceiling downwards. I checked the bathroom which is next door- no problem there or anywhere else in flat. just on small cupboard which contains shoes and coats. I live on the 3rd floor of an apartment block so area where mould is no where near an outside wall. I dont know why this is. There is no window in bathroom or kitchen just bedroom and living room but noproblem in those areas Any idea?
    Any ideas?

  53. Hi. I live in a detached bungalow in the countryside. I’ve notice in 2 bedrooms white mould circles covering every bit if tge ceilings. It’s not easy to notice because if the colour. When I touch with my hand it comes off like a powdery substance. Bedroom floors are very cold in winter. Can you tell me why this might happen on ceilings?

  54. Hi
    I have recently inherited a bungalow and are about to build an extension and insulate the house,
    We have noticed that when we take anything out of the house we get a bad musty smell from it however we do not get the smell while we are in the bungalow .
    We have an architect for the build and he does not seem unduly worried about this but we are quite concerned could you give us any advise
    Kind regards
    Sue

  55. Hi,
    I have problems with damp and mold – my gable end wall is full of green moss.
    I’ve had report done and been told that the bricks on the gable end wall are perishing some have perished – the Landlord saying it condensation causing the damp and mild.
    Mr personally think it could be penetrating damp.
    Don’t know who to turn to – any advice or help would be much appreciated.

  56. Hi
    I have 300 year old stone cottage. It’s stressing me out the amount of mold I get in cuboids, around the windows, corners of ceiling. None downstairs only up. When I put the central heating on it gets duper jot downstairs but not up. It’s got worse since I had a vent put in bathroom when I switch the light of it comes on. Why has it hot worse and only upstairs.

  57. Hi I live in a two bedroom flat and have carports under the flat had to change all my bedroom furniture and it feels like all cloths are wet I do open the windows but the flat always feels like it is wet and very cold what can I do to stop this please help. Thank you .

  58. If this page still up and running?? Really need advice but have noticed a lot of people’s last questions have not been answered!

  59. My cavity walls were insulated with pellets,since this was done my bedroom ceiling has got black patches why has this happened and how do I get rid of this problem.

  60. Hi I dont know if this page is still active but I am in the course of renovating my house and am looking for a way to relieve the mould problem I have in the back room of my house. We have patches that seem to occur in some places on the wall. It appears to be on the surface of the paint and I would suspect condensation build up as this at the most northerly facing point of the house and only happens when it gets colder (i.e. it can be perfectly dry in the rain but soaking on a cold dry day). I will be using 38mm cooltherm boards to insulate the inside wall however this will not solve the condensation problem I have on the windows. I have also started to notice mould spotting on the ceiling. When I enter the loft it feels quite damp and there is condensation build up on the felt. The only cheap solution I seem to be able to find for these issues is something like the Drimaster 2000 but I’m not sure and I know if I go to any type of builder or anyone like this they are going to quote me into the ground and tell me that this is a serious issue. So do you think this drimaster is a possible solution for me, have you heard of them and what do you think of them/can you recommend something else?

  61. Hi, we have a flat roof house with no loft and we get condensation and mould in the house, is there a temporary measure to cure this until we have the funds available to put a roof on the property.

    Cheers
    Ade

  62. Hi there
    We have bought a timber framed house built in the 80’s. We gutted it and renovated it including changing all the plasterboard and insulation inside the house. However there were no vents in this house ever and the actual timber of the structure smells and I can smell it at times in some of the rooms from the sockets etc. Is there any treatment that can be sprayed into the wall cavity to rid the timber frame of this old musty smell? There is no damp anywhere in the house

    Many thanks

    Ger

  63. In the past year we had pvc double glazed Windows installed throught the house now we have a black mould appearing, we also have condensation on window this is happening in our bedroom only. Someone suggested that we should have vents fitted in walls in all rooms.

  64. I have just recently found black mold on the external vents in my kids rooms. They are on the second floor of our house, and I noticed it on the high ceiling in the middle of our home as well. I do not see this elsewhere. We recently had a lot of rain (caused flooding for the city..was bad) . We had a leak in our master b-room but fixed it and have not had additional sings of leakage.

    I am trying to figure out what to do. Do I get my vents cleaned? Do I just clean the external vents, spray around the vent and then control temperature? Do I have a leak I do not know about?
    Who do I call to get assistance that will not rip me off? Please assist

  65. Hi, I’m looking at purchasing a house but on viewing the property today I can see the upstairs bedrooms (3) in corners of these rooms and above Windows there is Mould, the estate agent told us that the owners have been abroad for 3 years and the property had been left like this to fend for itself. If I follow your guidelines on washing the Mould and then using a dehumidifier etc then getting a specialist in for the DPM can you see the Mould being a huge reason as to why we shouldn’t buy the property.

    Thank you

  66. Hi I am having an single storey extension built and the builder has left a 4×4 ft MDF board inside the extension will this cause me damp problems later on.
    please advise P

  67. Hi, have the same problem as everybody above…

    the external lateral wall is somehow dump because we get an awful mouldy smell in the room underneath the stairs and lately just noticed in my wardrobe which is agains the same wall.

    Any indication????

  68. Hi Helpful engineer. I recently bought and renovated a terraced house in Cork (completed April this year). We are mid terrace. I had v. limited funds so did what we could. The builder was an insulation specialist, so I was a bit alarmed to recently find green mould spores growing up the walls by the stairs. There is black mould growing around all new double glazed pvc windows and sliding doors. He told me it was due to poor ventilation and there is nothing that can be done at this stage, other than keep the house to a mid level of warmth to make sure the walls don’t get cool. I am also paranoid now that it is growing in the insulation, as they left a hole in the bathroom wall where an electrical cable comes out and I have not had time to get this finished! The clothes in our bedroom had this green mould growing on them, and I can ‘taste’ it if that makes sense, but no major signs of it on bedroom wall – only around windows. I am now very worried that it is airborne. My son is having bad cough, excema and I’m wondering if this could be the cause.

    Also, there was a patch of damp in the ground floor bathroom which we attributed to a leak due to a bad seal. However, I notice also that the grout along that wall is cracked and I am worried it is rising damp.

    There is no vent in the front or back of the house so only ventilation is windows.
    The loft / roof is not completed yet so no felt on roof and a plastic membrane covering the underside of roof in the interim.

    This work is going to be completed in the next month or so, by a different builder due to some quality issues with the previous.

    I hope I don’t have a sick house 🙁 What would you recommend to do?

    1. Hi
      I suggest you install humidity tracking extract fans in bathrooms and kitchen and install a PIV loft unit this will force ventilate the home assuming the builder installed vents as per building regs.Did you avail of the SEAI grant for works. Did builder offer the mechanical option when carrying out works. If not he should have and got you to sign a declaration of works stating the offering and the potential results of not taking it up. Try HESEnergy.ie they install systems for the council and sure they’d be happy to advise.

  69. Morning! We’ve just finished renovating twol brick based cottages that have been converted into one cottage prior. They were built in 1860. There were two wood/stone spiral staircases running up either end of the property. The one side had already been blocked off and there have been no problems however we decided to block the other one off ourselves. We are at the end of a terrace and the one which we blocked ourselves is end wall. We have recently discovered the recess in our bedroom which the original stairs came up has started sprouting yellow/white mould and is very damp. I’m a decorator myself and I’ve noticed that the wallpaper is starting to come away from the walls also. When we started to clean the stairs we found that a lot of it was rotten so we cleared the damaged areas, used leftover render from the dmp course we had done and turned it into a storage cupboard. We have a long radiator under the front window that doesn’t give much heat so we are waiting for a new radiator to be fitted nearer the recess to see if that can help. We’ve also been told that the roof is shot to bits and are looking in the region of £4000 for a new one. Any ideas what we can do to solve this mould problem?

    Thanks, Graham.

  70. Hi Helpful engineer. I am renting a flat above a pub. The flats on each side of me are empty and have being for 3 years since i moved in. The bathrom has mould on the wall beside the window and the windown sill in the kitchen has mould as well. Upstairs i had stains on the Roof but it was loose tiles and that was fixed last year. The bathroom and the kitchen are both at the back of the house. How could i fix this?

    1. Hi Your land lord has a legal responsibility to provide you with a safe living enviroment. If you live in Ireland you can call the ptrb to get some more detailed advice on how to deal with landlord . What your rooms need are humidity tracking extract fans. Ideally not axial type as they don’t have much pushing power but a centrifugal model like the eco air or filter less models from S&P

  71. Hi, can you give me any advice? We have had French windows installed in our bedroom leading out onto a balcony. Maybe 3 years ago. Everything great. Then this last winter we have started to get black mould down in the corner of the wall near the base of the doors. The wall feels damp there. The wallpaper is beginning to wrinkle a bit. I assumed that the mastic seal around the doors had failed, and water was getting in through a small crack, so there should be an easy solution. I had builders in on something else, so I got them up to look at the mould and ask if they could put more mastic around the outside of the doors to make sure the seal was still good. They took one look and said it was condensation, not penetrating damp, because it was black mould and you wouldn’t get black mould with penetrating damp. That seems odd to me. Yes it is our bedroom so we sleep in it every night, but we never get moisture building up on the windows (all double glazed, with cavity walls, although the cavity walls are not filled due to proximity to the coast). I cannot see any other sign of a condensation issue anywhere else in the room or the house. It’s a good dry house. There is a fireplace in our bedroom which must give some ventilation for moisture, and extractor fans in all our bathrooms. Any thoughts – can you still get black mould with penetrating damp from a leak in mastic around door? Is the builder talking rubbish?

    1. Hi
      The problem is a high humidity in the home. It’s not showing on the windows as they are more insulated then the wall the problem is showing on. Humidity’s goal in life is to be water again and what it needs is a cold surface to achieve this. As we strive to insulate our homes more which is good as we reduce our energy costs. We end up living in a bottle. All habitable rooms should have a vent of some forms (trickle vents in window or wall vent). The fireplace may seem like a great vent but there is no motivation for the air to change or maybe too much resistance in it to allow it to happen. I suggest you look into a PIV positive input ventilation system and mechanical fans in bathrooms. These if installed correctly will constantly dilute the humidity in the home while also having the the benefit of improving the air quality in the home.

  72. Hi having mold issues ever since neighbor started developing his home.
    I have mold appearing in 3 places, since he started. There was no issues with mold before, I keep the place heated to 18c the thermometer is in the hallway. They are trying to blame me suggesting I am responsible. I have to seal the Windows in the sitting room because of the amount of dust, but the mold is in another room, the windows have ventilation holes.

  73. The area where the mold is coming from is in the bedroom those windows have ventilation holes, and mold next to the entrance of the flat which is on the partition walls.

  74. We have mould in our pantry, sons bedroom built in wardrobe the end were there is an outside wall, my daughters bedroom wall, again an outside wall, downstairs toilet, bathroom ceiling. The house was built 1930’s. We cannot have cavity wall insulation because there isn’t a cavity. Infact we just have the one brick, no breeze blocks! How do I solve the problem? My hubby is in denial, saying ” don’t worry it’s condensation, every house has condensation”. What I can’t understand is homes much older than mine seem to be in better condition when watching a place in the country. Any advise would be gratefully appreciated.

Leave a Reply

Your email address will not be published. Required fields are marked *

hublot replicarolex replica uktag heuer replicareplica rolex salerolex replicarolex replicarolex replica salerolex replica