Mould, a microscopic fungus, grows in damp places and can cause serious health problems. It is often found in homes with fuzzy black, white, or green patches on the walls and a damp and musty smell. The Stachybotrys chartarum, a type of black mold, can cause chronic health issues. To get rid of black mold, it is essential to locate the source of mold in your home, which can be identified by its often-slimy appearance.
Mold growth on interior walls and ceilings is caused by excess levels of moisture, which is necessary for the mould to bloom and multiply. High humidity levels can create ideal conditions for the mold to bloom and multiply. Common causes of mold growth on walls include high humidity, condensation, and water leaks. Condensation from everyday activities is one of the main causes of mold buildup in properties. Key spots for mold growth are around window frames and bathrooms.
Water damage is the most common cause of black mold. If water seeps into your home and stays there for long periods, it can create an ideal environment for mold growth. Rusty indoor pipes, condensation on the inside of windows, and condensation forming on the walls are some of the factors that contribute to the growth of black mold.
To remove mold from your home, follow a four-step process: remove moldy drywall and other materials, kill the mold, encapsulate remaining mold, and rebuild part or all of the wall with new drywall.
📹 The Ugly Truth About Black Mould
Roger looks at the problem of ugly black mould and explains how we can avoid it. Why does mould grow on walls, why does mold …
Why am I getting black mould on my walls?
High humidity levels in homes can cause black mould growth on walls and ceilings, often starting in the corners of the room. Poor ventilation is often the cause, and regular opening of windows can help encourage air circulation. Penetrating damp can cause mould to show at any height, as dampness penetrates through the exterior wall to the interior wall, often from wind-driving rain. Detecting a musty, stale, and earthy smell may also help identify the growth.
How do I get rid of black mold on my walls?
In order to eradicate tenacious black mold, it is recommended to utilise a solution of water and detergent or vinegar and water. In the case of particularly tenacious black mold, it is advisable to employ a commercial mold remover. Once the area has been cleaned, it is essential to ensure that it is completely dry and well-ventilated to prevent the regrowth of mold.
Is black mold on walls toxic?
Black mold can cause respiratory issues, allergic reactions, respiratory infections, and toxic effects. It can irritate the respiratory system, leading to symptoms like coughing, sneezing, wheezing, sore throat, and nasal congestion. Individuals with asthma or allergies may experience exacerbated symptoms. Some may develop allergic reactions, ranging from mild to severe. Prolonged exposure to high levels of black mold may weaken the immune system, making individuals more susceptible to respiratory infections like bronchitis or pneumonia.
In rare cases, prolonged exposure to high concentrations of black mold and its mycotoxins may result in neurological symptoms like headaches, dizziness, memory problems, difficulty concentrating, and fatigue.
Not all black molds are toxic, and not all individuals will experience severe symptoms. It is recommended to take infestations seriously and address them promptly to prevent further growth and potential health hazards. Identifying a black mold infestation is difficult, but a trained professional can accurately diagnose it through a professional analysis.
How do you stop mould on internal walls?
To prevent mould growth, use a dehumidifier, wipe down surfaces affected by condensation, and use disinfectant or fungicidal wash to remove mould. Mold-inhibiting paints and sprays can also help reduce condensation effects. Check all accessible plumbing for leaks, guttering, down pipes, overflows, roof leaks, damaged walls, and high garden or path levels overlapping the damp proof course. Follow manufacturer’s instructions and use mold-inhibiting paints and sprays as needed.
Can mold behind walls make you sick?
Inhalation of mold spores, which are ubiquitous in the atmosphere, has been linked to adverse health outcomes in some individuals. Inhalation of mold can result in the development of allergic and respiratory symptoms. The extent of mold’s adverse health effects is contingent upon a number of factors, including the presence of preexisting respiratory conditions and compromised immune systems. This includes individuals with HIV/AIDS infection, organ transplant recipients, and those undergoing chemotherapy.
Can you get rid of black mold permanently?
To eradicate black mold in an efficacious manner, it is imperative to ascertain the underlying cause and utilize efficacious solutions such as bleach or baking soda to eradicate the mold from the surface. Once the underlying cause has been addressed, it is advisable to utilise a dehumidifier in the affected areas in order to reduce humidity levels. Subscribe to our mailing list to receive updates on the latest design ideas, celebrity homes, gardening advice, and shopping round-ups.
What kills mold permanently?
In the event that detergent proves to be an ineffective cleaning agent, the removal of mold can be achieved through the use of diluted vinegar and a microfiber cloth. In instances where vinegar is also ineffective, the application of diluted bleach or a commercial product may be necessary.
What kills 100% of mould?
Mold is a common problem in buildings, and removing all mold-infested materials is the only way to kill it. However, for smaller amounts of mold growth, a fungicide can be used. Cleaner Guys, a professional mold inspection and removal company in Washington State, has over 20 years of experience and is knowledgeable about mold inside and out. They are alarmed by common suggestions on the internet for killing mold, such as bleach and vinegar.
Cleaner Guys aims to set the record straight by addressing what truly gets rid of mold and what doesn’t. They also provide information on what mold looks like and what causes mold. They emphasize the importance of hiring a mold removal company to ensure the safety and effectiveness of their solutions.
Can I remove black mold myself?
Black mold can be removed by yourself, but it’s best to consult a professional for toxic species that can cause severe health problems. RPF Environmental, a qualified mold inspection company, can help you understand your mold problem and provide a solution. Handling mold infestations yourself can be harmful, so it’s best to consult a professional before attempting to remove it yourself. If mold is found, immediate remediation is necessary to prevent further spread.
Is mold behind drywall a problem?
Mold on drywall indicates a deeper issue in the stud space behind the wall, requiring replacement. If the mold is found early, it can be removed using natural cleaning solutions like baking soda or chemicals like bleach. If the mold is on painted drywall, it is easier to clean as paint provides a barrier, and mold hasn’t penetrated the surface. A good cleaner and elbow grease are needed to remove the mold. In severe cases, mold can be removed using chemicals like bleach.
Is it OK to be in house with black mold?
Black mold can cause health issues and is not recommended for living in a house with it. If living in a house with black mold, seal off areas to reduce contact. While individuals can remove it themselves, proper precautions are needed to prevent further damage. If a mold problem is noticed, it is advisable to contact a professional mold remediator. Effective options for killing black mold include mold removal products, white vinegar and baking soda, hydrogen peroxide and water, and borax and water. Bleach is not as effective as other options.
📹 What’s causing black mold to be growing on an interior wall?
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Great article. I live in a rented second floor flat next to a major Scottish river. The first winter I was there it was bitterly cold and the heating didn’t help. Had black mould in the kitchen, living room and main bedroom. After bleaching the walls of the mould I did a bit of reading up and bought a 3L condenser dehumidifier. The first time I ran it I was shocked when it filled up in only a few hours. Ran it again, did the same thing. But it made a huge difference. Ever since over the winter I leave it running for around six hours a day, usually overnight, or when I’m cooking, using the tumble dryer or until it’s full. Thanks to the air being drier I’m finding the heating needs to be on less. As for ventilation the kitchen window is open for an hour or so a day and the bathroom window is left open permanently a couple of inches. The mould has never returned.
It’s great! My shed has been completed and it turned out nice looking and sturdy and it is way better than the sheds that many of my neighbors had put up. Of course, I’m pleased with the outcome and this Ryan’s youtube.com/post/UgkxGZedDTcDfgD7fG_uU4esfx_EgxzlY2_1 Plans was extremely useful to me as a guide.
I’ve been refurbishing bathrooms for 35 years and thought i’d seen it all until a job i looked at last winter. The house inside was a total mess, disgusting, but that’s a different story. Every window sealed and taped shut with quilts nailed over them. Extractors all blocked up and sealed. The radiators on full blast covered with soaking wet washing. But it was the bathroom, never seen anything like it. The ceiling and walls were black and hand on my heart as i was standing there it it felt like it was raining from the water droplets falling off the ceiling. I could smell and taste the mould and just walked out. The people were the worst of the worst, rotting food laying around, dead rodents, cockroaches, i can go on and on. How people like like that is beyond me. Really bad.
It is not always a venting / lifestyle issue. My sisters flat had a broken gutter and it leaked water all over the outside wall which gradually seeped through that walls causing mould growth on that wall only. The cure was to fix the outside guttering, re-plaster / clean / re-paint the inside walls and also for safe measure add a de-humidifer on constant run, due to it being a small property.
Bought a house in the summer that was soaked with condensation and covered in black mould. It worked in my favour as it put a lot of buyers off. Previous occupants has blocked ALL the vents. I unblocked the vents, putting draught flaps up where appropriate, bought a 12 litre dehumidifier and borrowed another off my girlfriend. A few bottles of Cilit Bang black mould killer, a month of running the dehumidifiers almost constantly, and, touch wood, the mould and damp are held in check. I still run the dehumidifier on smart mode occasionally, just as a precaution, but it seems to have been sorted and the house is almost dried out. (it was soaked through)
I feel like everyone needs a beefy dehumidifier to keep mould in check on the cheap. Dehumidifiers are probably the best way to dry clothes inside the house on the cheap, it’s also very fast. Oh and in my experience putting large furniture up against the inside walls rather then the walls that lead outside helps with the cold pockets that may lead to large flairs of mould.
spot on Roger tenants switch off bathroom extractor fans is very common, plus one thing you did not mention but squeegeeing the bathroom tiles and shower enclosure around the shower area when used pushes that water down the drain that would otherwise evaporate into the house, that reduces the moister in the environment also
We suffer from mould. Yesterday a friend gave us a condenser drier. I dried 3 loads of washing. I got 500ml from 1st load. 800ml from 2nd load and an amazing 1500ml from drying 3 bath towels. Unbelievable how much water drying clothes on radiators puts into the air Edit* the extra money on electricity was saved in gas
Great concise and comprehensive talk Roger, I too am considering my position over MEES it will end my time as a landlord (50 years). In my experience, everything government has ever done to the PRS has cost the tenant more and they never get past the innate anti landlord position. I’m going to forward this to my MP who asked me about mould the last time we met.
I had the opposite, rented a house that had the exterior render put on too quickly before I moved in, and it cracked and expanded from the wall, all down that side was mould on the inside, even after showing the landlord and the council etc they tried to blame it on lack of windows being opened, drying clothes indoors etc, of which I never did. You could tell from knocking on the exterior how hollow it was near the cracks. Luckily I am out of there now and have had no issues in my new place.
I run a small handyman business. A regular thing I get is asked to look at ‘the damp problem’ by my client, the landlord, following a complaint from the tenant. Now some of the time there is a genuine issue with water ingress but I recon more than 50% of the time it’s actually condensation due to lack of ventilation.
100% right. This season you have two choices: be on breadline all winter and not have a mouldy house; be slightly ABOVE breadline and when spring rolls de-mould your house which goes in thousands of pounds… We are barely making ends meet but we will heat the house 3 times a day above 19degrees (and ventilate) just to prevent mould.
Condensation and mould is almost entirely caused by the lifestyle of the occupants not usually by the building. Inadequate use of heating, ventilation, drying clothes indoors, constant mopping of floors, not venting tumble driers correctly and over occupancy are usually the causes. In one case where I was inspecting a brand new property where it was built to the latest standards of heating. insulation etc. The lifestyle of the occupants had caused black mould to grow on every wall and ceiling in the property within months of them moving in! Discussions revealed that they had the same problem in their previous property, so in addition to inadequate use of heating we concluded that they had also brought over mould contaminated possessions which helped spread mould spores in the new house.
Double glazing rules changed from june 2022, all must be fitted with trickle vents, but exactly what you said, with heating costs through the roof people just shut them. I totally agree most of black mold problem is lifestyle problem, amount of times I have to explain to customers that windows do not make condensation. You can get condensation on the outside of windows at certain times of the year, I then have to try to explain to certain customers this is a good thing because it shows the heat is not escaping through the glass. Go back to the old public information films to explain basic things to the general public, seems like they need it. Nice article, love the rants.
Sometimes it’s best (and cheaper) to take a lot of wet clothing down to the local launderette. Yes, it might be 50p for only a few minutes of tumble drying, but the drums are huge and they heat up quickly. Tip: If you arrive and there are several empty ones, feel them first. If you can, pick a warm one.
You are right to bring this up Roger. I think when you get exposed to mould it can get in your lungs and specific types of immune cells will attack it. Sadly I think it also attacks the lung tissue a bit and that can produce pain/tenderness when coughing etc. Also a symptom of infection can be itching on the palms of the hands and soles of the feet, perhaps even with small lumps or pustules. Defnitely something to take seriously and avoid.
Here are my tips: Leave windows ‘on the handle’ where a small amount of air can circulate or for faster effect open fully for only 5 mins then close to ‘on the handle’. This reduces the temperature drop from a longer duration which works against drying the air inside. I don’t like drying my clothes in a tumble dryer because it wears them out quicker and is expensive. During colder weather I hang them on a clothes horse in a small (but not tiny) room and run a dehumidifier to dry them quickly without increasing the moisture inside. The dehumidifier is cheaper to run than the tumble dryer (expensive tumble dryers have dehumidifiers built-in to reduce running costs). After showering use a squidgy to wipe down shower walls and doors so that water doesn’t have to evaporate into the house. Doing that and opening the window means I don’t need to run the extractor fan in the bathroom. I’d keep the fan on for others who aren’t going to be so cautious.
I have now tackled my mould issues in my house thanks to what I have learnt from YouTube articles like yours. I have now enforced all showering and bathing be done with the window open. Cooking is now down with the window cracked open. Unfortunately my double glazing does not have trickle vents. So the best I can do is have the entire window on the first latch. Next task will likely be a extractor fan in the bathroom and the kitchen.
As a property inspector I’ve found black mould can be caused at high level by blocked gutters pushing water under the lowest roof ridge and if the mould is only on the window frames or the coving above and to the sides it’s usually either failed external mastic seal or failed render where the window was never mastic sealed
The best time to ventilate the house is just before you go out. Open the windows let the air circulate for half an hour and do some house work to keep warm. Then close the windows and go and do your shopping etc. When you come back the new air will have warmed up a bit from the electrics, sun etc even if you do not have the heating on.
I had really bad mould on my window frames. Not anymore. Make sure you take these steps: 1. Ensure there is a timer on your bathroom extractor fan and it stays on minimum half hour after you have a shower 2. Dont dry clothes indoors. If you do, make sure there is an extractor fan in that room (bathroom or utility room usually) and leave the extractor fan on 24/7 3. Open bedroom windows when you get up in the morning and leave open for minimum 3 hours. I generally close mine when i get home from work. My windows are upstairs and have the anti-burglar latch that allows them only open a few inches. 4. Make sure you always turn on the extractor fan when you are cooking. 5. Get mould treatment spray (its mostly bleach) and if you see mould on your bathroom ceiling spray it straight away and dont be tempted to then wipe off the mould with a cloth, leave the bleach to take effect and within 24hours the mould will have been killed and disappeared. 6. If you remember nothing else remember, fans and windows.
I work in social housing and see this all the time, we had one who was blaming us for her children being ill, mould everywhere it was awful- turns out she was using a vented tumble dryer without venting it 🤦🏻♀️🤷🏻♀️ all that hot moist air was pouring into the flat! Dehumidifier for a week, 2 humidistat fans, a vent fitted for her tumble dry and surprise surprise it’s gone! I think a lot of the problem is around education and these scandalous company’s who knock doors and encourage people to sue- taking money out of the system. Budgets are already under strain due to the constant government cuts- don’t get me started on that 😂
We went to see how bad the condensation issue was with our rented house. As we walked into the house our glasses instantly steamed up and had water dripping off them! They had washing drying everywhere downstairs and their three kids were having a steaming hot bath… Not one window was open. The tenant complained the house wasn’t insulated enough which was causing the problem. After they refused to accept they needed to open the windows to let all the moisture out of the house we told them to leave.
Perfect article Roger. I am renting and I did make the mistake of drying my clothes in my room and keeping windows shut and yes, I did end up having respiratory issues….. all my own fault and I put my hand up to it… now, in December 2022, with this cold weather, I have been keeping the window open during daylight, and not only did my respiratory issues go away, but I actually enjoyed the ‘freshness’ in my room. None of this was ever intentional, it was simply that my room was often cold (it’s an old house) and so the window would remain shut. Clothes are no longer ever going to be dried in my room, and I hope that my breathing issues will go away (they’ve certainly improved but I don’t know if they’ll last for ever – I’m hopeful that ever a period of months I’ll be okay). Moving forwards, please could you do a article on tackling the removal of mould on windows – ours are old wooden framed ones (with sashes some of them) – also on one of my windows the owner has secondary double glazing which of course has only made the condensation worse, so now I just keep that open all the time…… Great points made in your article, especially about governments and selling off council houses. I personally think that literally every single problem we have here in the UK can be boiled down to the cost of housing. Were housing to be simply affordable, we would all be better off and could lead quality lives, not just the affluent/wealthy.
Great article and what most of us have known for years. Sadly with energy costs as they are trying to get people to ventilate their home is a tough sell, especially during proper cold snaps like we’re having now. My front room was 10 degrees when I came home the other day, it barely reached a comfortable temperature before the heating went off before bed, with windows open it would have been like sitting in a barn. The bathroom is permanently vented because of an open extract fan, plus I open the window when having a shower and drying washing in there, so far no problems.
So well said! We rented property and this was our biggest issue people complaining a perfectly decent flat was mouldy when it was actually them who made the property mouldy, we would have a tenant keep a flat perfect for 10 years, move out and within 6 months the next tenant would say the flat was mouldy.
One thing not mentioned in the article are plants. Speaking from my experience, a massive plant lover, I had 40 large plants in my flat at one point and they drink a lot of water. Found mould growing pretty fast so had to reduce the number of plants in the space and yes, drying the washing inside was a terrible idea.
I went to a flat where they were concerned that the roof was faulty. Every surface / ceiling was covered in mould. I knew there was nothing wrong with the roof. In the kitchen – they had a tumble dryer. The extract hose was inside. I asked – do you put that hose out of the window when it’s running 🤔 There was the problem! I’m here all day
We had bad problems in our bedroom window reveals and the wall above the window. Actually wet with condensation. Turned out the lintel was full width concrete. Also the slope of the roof rafters meant the wall above the lintel was single skin. All this behind the fascia boards. With great difficulty I stuck 25mm kingspan on the outside of the wall and lintol (from inside the roof!) Then chased all the plaster out in the reveal and fitted marmox board and had it skimmed. Problem cured. I would say have extractor fans in the kitchen and bathroom. Use a compressor type of dehumidifier (cheaper to run than the dessicant disk types) in the room you dry the washing.
This is the exact problem my other half has, he works as a Technical Manager for a large devloper. The purchasers often complain about condensation etc. and when investigated its because they’ve closed the trickle vents, they just don’t get it even though it’s been explained to them. They blame the builder.
Excellent. I wish more people would see this. What a lot of people don’t know is the huge capacity of air to hold moisture. At 20 degrees C, one cubic metre of air can hold 17.3 grams of water. In a living room measuring 7m x 5m there are 80 cubic metres of air. The amount of water sloshing around that you can’t see: 1.4 litres (that’s well over 2 pints for the oldies). For every 10 degrees that the temperature goes up, the capacity of air to hold water doubles!
Some random notes; Dew point is important. This is the temperature at which moisture condenses (turns from a gas to a liquid). We live in an old house so have to waste a lot of heating; old houses like to breathe and that is simply a fact that has to be accepted. The healthiest target for humans is a relative humidity between 40-60% and a temperature of between 20-22c. We have a zoned heating system (evohome), which keeps every room in the house a constant temperature, heating the house properly and evenly and cracking windows is enough on its own, though is wasteful. Also having humidity sensors around the house so that we know we’re in the right temperature and humidity range. Those driers for clothes that are have fans aren’t all a con, we got a JML dribuddi (yes I know JML) and it’s good for clothes that hang, can be used in the bathroom, dries much quicker than a radiator and holds a lot more clothes, and uses between 0.8-1.2Kw which is a lot less than a traditional tumble drier (5-9Kw). To note that you can now buy a heat pump tumble drier which are very much more efficient. I will aim to buy one of these in future.
As you say, open a windows as often as you can. Dry air is easier to heat as well. This time of year my morning chore is to go around every window and wipe the condensation off. I leave the windows open for a while and wrap up warm and the house is generally fine til the next day. No central heating or bedroom heating required just a wood burner in the living room. Electric blanket for going to bed is the hight of luxury. Lovely. I check for mould every day this time of year. When I find it I use any old spray bottle filled with Asda cheap bleach, it’s very diluted already so little extra water is needed and spray the effected area lightly (do not soak) and it’s gone a short while later, if not just repeat. Of course protect yourselves and any are you don’t want bleach on. been doing this for over thirty years with no problems.
Skill Builder You my man Are so down to earth. I regard your information articles as some of the best quality advice on heating and plumbing. Keep them coming my man. My own circumstances are – My home was built in the fifties. There is still a chimney running from a fireplace in the iving room. My fireplace is closed off except for a vented plate. The house is completey double glazed, but the front door is purposely not draught-proofed. The result is that the chimney draws air up it due to wind. The air that replaces that chimney draft is sucked in via the front door and by the time it gets into the living room the cold air has been warmed up a good bit. The hallway is bloody feezing in winter but who lives in the hallway. The only room that suffered from any mould was the bathroom. That had an extractor fan fitted some years ago. The fan comes on with the light switch and keeps going for twenty minutes after the light is switched off. Mould gone. Upstairs is never a problem At bedtime, the heating is off and the windows are opened to get circulation going. Folk I have encountered who have the black mould issues all have the same problem. Not much air moving around the rooms. In all of them I find they keep all their windows shut – even at night. Why? If the windows are opened – what is the point of having double glazing and draft proof windows !!!!
thanks roger, that was spot on. we are recent home owners and had new mould as a welcome present this winter. indeed, heating and ventilating are key, costing around 10quid a day. we started measuring in all the rooms and also got a dehumidfier that pulls 10L of water out a day, the thing is a beast. now we’re around 50RH in the house, and it finally feels cozy. moisture and mould have been new to us since moving to the UK, but is manageable with vigilence. do you think indoor air filters might help as well?
Landlords selling up is pretty great. I’ve never owned a car, contract phone, didn’t eat avocados or any other bullshit the daily mail will claim millenials do. Now that I’m finally on the ladder my mortgage is 50% of old rent. Same street, same 2 bed terrace but now I easily install those extractor fans myself in the first month without being a penny down compared to renting the mouldy place next door.
I absolutely love your website. I think my husband is getting fed up of me telling him about all the tips I get😂. It’s true about opening windows, I’m always flinging them open first thing in the morning no matter what the temperature..even if it’s only for 30 mins. I also have a dehumidifier which I sometimes have overnight( cheap to run too) in the bedroom or in a room where my washing is drying. If I do find any mould in the bathroom it gets wiped with hydrogen peroxide. Fresh air is a life saver so opening a window and putting on a jumper is easy. We are not a rich couple either👍 Sorry for long waffling😂
Great informative and factual article, thanks. I’m a chippy. I had mould toxicity from exposure to toxic mould while renovating a property. Ironically I was re-installing a shoddily built stud wall in our house, in order to provide adequate support for a MVHR unit at the time. It floored me for six months. When I removed the stud wall I discovered the previous owner had “installed” foil roof insulation between the studs which had sagged, touched the gable end wall and caused condensation. The wall was literally covered in black mould. I can absolutely qualify everything you’ve just said in this vid. I’d just like to add though that toxic mould exposure can also cause inflammatory responses in joints, extreme fatigue and lethargy, and cognitive issues. In other words it messes with your head too! Really messes with your head in some cases. It also doesn’t matter what colour the mould is, they can all be toxic to humans and animals, especially when they release spores. It’s a very serious issue and should be dealt with immediately to avoid illness. Outlay for a MVHR system can be pricey but since fitting the MVHR in our place, our heating bills have dropped massively. It will have paid for itself in five years. If you’ve no option but to dry washing at home, get a dehumidifier and keep it clean. And re-decorate with mould resistant paint as soon as you see mould. Best thing for cleaning mould off surfaces prior to cleaning or painting is white vinegar.
I never had any black mould in my early 1700’s home until I changed the windows. Now its a constant fight. Cleaning the mould with Sodium Hypochlorate (bleech) kills it but it comes back every year. I have no insulation, cannot insulate. I have 24 inch solid stone walls. I need my old drafty windows back. I’ll just burn tyres to keep warm.
You need to mention clearing out extractor fan ducting. Just changed mine(had easy access) and it was blocked up with spider web. I fitted this new one 10 years ago and should have cleared this out a few years ago. The fan motor was making a funny noise so immediately investigated. Mentioned this to a retired plumber friend and he says they are normally blocked with skin powder – he has cleared out loads over the years. Our daughter has a problem with mould – 2 things – terraced house adjoing wall is stepped above the roof(on a hill) – so this wall gets rained on and simply soaks into this adjoining wall and hey presto – mould. Means the wall(above roof) needs coating with a brick waterproofer. Plus gutters cleared – full gutters means a possible overspill – again onto the wall. In very old prewar houses there is no cavity so again moisture drawn in and down the walls.
Excellent article mate! Desiccant dehumidifier is the way to go for the poor wouldn’t you reckon? It would pull the moisture out the air, allowing the clothes to dry even with minimal heating, while also keeping the environment inside healthy to live in without the side effects of damp/mould, They just have to layer up put some thermal joggers on! But from my understanding their around 180-680 watts so very economical vs a tumble dryer or heated clothes airer, & you get the dehumidification as a massive bonus to the structure of the building and the persons living inside👍🏻
I Love this guys outlook TBH. I’d struggle to see someone disagree with this. One thing that helped us was making sure the bathroom door is shut, and sealed (no gaps for moisture to escape from). And using the anti-perspirant on odd bits that cropped up (sounds mad, anti-perspirant on a tiny corner of mould, caused it to go white and get hoovered up). We didn’t have to open all the windows, but we do use an extractor from bathroom and I’d like one in the kitchen. Ventilation and isolation is key. (so open-plan I reckon is a terrible idea for a house)
Great article Roger, I do love your rants! I used to live in an small 1st floor 1 bed flat in a purpose built 1980s block. Not the best design, no window vents, no air bricks and it had an internal bathroom. It did have working extractor fans though. To cut a long story short, I went through quite a bad period in my life and I let the flat go to sh*t. Over a period of 4 years I don’t think I opened the windows at all. The bedroom wall and ceiling was the worst, black and other colour mould all over it, as well as mould on my mattress and furniture. I eventually sorted myself out and redecorated the flat. After that, I opened the windows for at least 30 minutes every day and the mould never came back. It makes a huge difference and proves that you can control it even in property which is not of the best quality.
I see similar comments here but I lived in a house for 5 years, then rented it out for a further 5 years without issue….then the last tenants moved in and within months were complaining about mould. I went to inspect and they had clothes drying all over the house. I advised them to pack that in and open windows more often but it continued. The estate agents managing the house for me were piling the pressure on for me to fix it as it was a heath hazard to the tenants. Ended up paying for a specialist company to survey the house and the outcome was as you said in the article, the lifestyle of the tenants and nothing to do with the building. I ended up selling the place to get rid of them and the hassle. Will never be a landlord again!
I once looked at buying a heated clothes drying system then got put off when I read it releases so much moisture, so I did a little more research and bought a compressor dehumidifier and my clothes are dry in mere hours rather than days, have also made sure extractor fans have been installed in kitchen and bathroom. So I’m hoping my investment will pay off in the long run cause mould is a bloody nightmare!
Finally a common sense article that backs up what I’m trying to tell my wife, I’m currently in the process of insulating the house, started replacing windows that make the issue ‘worse’ and exactly what you say is backing up everything that I say. We’ve fitted the PIV after the recommendation from one of your other articles where you was having a chat with an installer, I’m doing all the bedrooms first because everyone spends more time breathing in there. Thanks for another great to the point rant Roger 👌🏻
i found mold around the windows in a few rooms and realised it was because the old mastic sealent was dry and knackered so i have cleaned up any damage treated it with anti fungle and mold, and repainted over the damage, re sealed the frames and problem solved, i find a lot of the time it is just poor insulations, knackered seals, and people that just can’t be bothered to deal with it
It seems very difficult to convince people that drying clothes on radiators or other devices that are not venting to outside is the worst thing they can do. Seen the problem of black mould caused solely by excessive humidity and insufficient ventilation many times but persuading occupants to rethink their way of living in the house is a difficult bridge to cross.
I live in a relatively modern house, 30 years old. Well looked after by me, constantly maintaining and renovating it. Recently had all new windows, soffits etc. But we still get condensation on the windows, and have mould in one of the bathrooms that I clean off every month – something I’m trying to avoid in my new bathroom project. It’s just a fact of owning a house, due to the reasons you mention in this article.
I have a question tho. I have a Humidity reader inside my house and its around 60-70% humidity during the winter. I also have one outside my house and it reads 90-100% humidity. If I let air in from outside wont I be technically exchanging air with more water in it and therefore raise my humidity levels inside instead of dropping them by opening the windows and doors?
i work for a housing provider and we use 24 hour slow speed continual extract but in with their rent the heating is provided for them so no damp and no worries from them about heating costs and the properties are always damp free when tenants move out private landlords probably could not afford this but a lot of larger groups could do more in supply of suitable systems without financial penalty
PIV does work, but it does also increase the bills, you do not need trickle vents for it to work. Do the maths first to see if you or your tenants can afford it. You put it in and hard wire it so it can’t be turned off. Whilst what you say is true Roger, you’ve missed something out. At the moment it’s very cold and very still, even in a good performing modern house built to current standards and building regs there can be condensation in the loft NO MATTER WHAT YOU DO! There simply isn’t enough air movement in the loft space to shift the damp air, this is coupled with the already damp air out there. There has to and hopefully will be a change in material and the regs to alleviate this. It’s purely caused by the amount of insulation we have to put in, roofing membranes and our climate. This Winter there will be a huge amount of damp issues in houses, more than ever before.
I have a Karcher Window Vac, and I use it indoors to gather up any condensation on the double glazing, bathroom, and kitchen. Also, it is worth purchasing a small hygrometer (very cheap) to check the humidity in your room stays below 60%. If the humidity in the room is higher, you must take action. I dry my laundry in the toilet / shower room, and keep the door shut and the window ajar – no need to heat that room at all. If you need to keep the sitting room warm (and the window closed), do not dry clothes in there.
I rented a house from sanctuary housing and had to report mould to them. They sent a bloke out to have a look he was about 60 plus and honestly I couldn’t believe what he said to me. Regarding the black mould situation he said ” it’s not dangerous to your health unless you LICK IT ALL off the walls. Needless to say I through him out of the house. As for the not venting the house we live with windows ajar in all the rooms so not venting moisture wasn’t the problem with the cause of the mould.
Yes, Roger is right, for most people the answer is to open more windows and ventilate … Yes there are other factors but over 90% of the time the problem is not enough ventilation. Stay healthy Better to open the windows and be a bit cold than to be snug as a bug in a rug with mold present… Remember mold is a killer which is easily prevented !!!
I agree that it’s a modern lifestyle problem but there are still ways of controlling the situation My 1935 house I’ve lived in since 2000 has always suffered with moisture and mould that we’ve always sprayed and scrubbed away For years I had 4 dehumidifiers on all throughout the winter to control the situation definitely not a cost affective solution I now have a piv system which was relatively inexpensive The Problem disappeared overnight and I no longer have any dehumidifiers on I really couldn’t be happier with this product best thing ever
Would love to see a article on mechanical ventilation. Is it possible to retrofit in the current housing stock to help contribute to overall system of warmer, mould free cheaper to heat houses ? Can smaller bore piping work? Can the upstairs be fitted only with a standard 2 up 2 down house and is that worth it?
You gave a good explanation about mould and highlighted a crucial point that moisture tends to accumulate in areas where insulation is inadequate. It’s worth noting that council houses in the UK are often very poorly insulated, and councils refuse to install even the minimum required insulation. This contributes to tenants having to block air vents that shouldn’t exist in the first place. One solution you didn’t mention is insulating flats and houses from the inside. In my experience, adding 50mm of Celotex/Kingspan insulation to walls and ceilings can resolve mould issues and reduce heating bills.
Excellent. At last, someone talking sense and telling it like it is. I bought a dehumidifier which costs me 7p per hour to run. Having it on a couple of hours a day has eradicated my condensation problem completely. The drier atmosphere also makes it easier (and less costly) to heat. This article should be a public information film shown on tv
When I was a landlord I found that the tenants never want to except responsibility for anything and expect someone else to sort it out and pay. When you see the news showing houses with loads of black mould, the first thing that pops into my head is why the hell have you not cleaned it sooner before it gets into that state, after all it usually starts out as a small patch and you can get very affective cleaners for literally a couple of pounds!
I spent over 13 years inspecting social housing for upgrades & refurbishments in 6 London Boroughs and lost count how many home I visited. I can count on my hands the amount of genuine damp problems I ever came across in properties and no one or no argument will ever change what I saw when it come to black mould. The ” Lifestyle ” term used = Lazy people, Ignorance, absolute lack of any air flow leading to condensation issues going on for years the tenant rarely addressed themselves that a bucket of hot bleachy water would have solved in minutes. I actually went into a Somali home on a Peabody estate and all the wallpaper had fell off the wall due to mould and the home being kept like a sauna, they even had some illegal copper heating elements around the bath to increase the temperature of the bath water, the list is endless at what I witnessed people doing to cause mould, yet they put more energy into complaining about it than actually cleaning it.
My partner is house proud and feels embarrassed to let anyone like boiler man, repairs etc come to our flat. The flat is clean but it is cluttered/messy, since my parents passed away a year ago before Christmas. I had to empty their council flat fast. I binned as much as possible, gave away stuff and to charity. But I had several bags/boxes of stuff that I hadn’t time to sort. So I brought them to my partner’s rented flat. There’s not much room so the bags are all around the staircase against the walls, in the flat. I’ve been meaning to go through them and make space but get emotional. I know I have to do it and I will. My partner worries about the weight in the flat and that all the bags/boxes (or some will say clutter) are causing damage or condensation in the flat and staircase etc. Can this happen?
Great rant Roger. Our bungalow had major issues with mould and poor air quality in our first winter. After installing a whole house ventilation and heat recovery system the problems went, air quality good. Yes it does require investment but we no long live in the 1950’s where I remember frozen condensation. Botom line life style is a major contributor to mould.
We had really bad mould in our 1800’s cottage,so we had the internal walls sprayed with cork and then skimmed before decorating.What a fantastic product it has turned out to be and it has reduced our energy consumption because the cold bridging has gone. You should do a article on Cork spray as it really is a wonderful material.
Brought up in a rent controlled house (just rooms really) in south London and through all the years (18?), I was there the landlord did nothing because the company which owned the house was unable to recover the costs of any repairs and/or improvements through rent increases. All those agitating for the return of rent controls such as they have in Berlin and other places need to be very careful what they wish for. Our houses (including many owner occupied properties, it’s not just a problem of the rental sector) are often already in a poor state, a few years of rent controls will just make more of them uninhabitable.
Thanks Roger. You’re spot on with your observations ref moisture and ventilation. I haven’t used our tumble drier ( 1 or 2 kw 😱) for many weeks now. We have a small 4m x 3 m conservatory that we don’t heat. I bought a 18″ fan (70w) . We put spun washing on a clothes horse in there and turn the fan on full directed at the clothes horse and open one of the small top windows. Depending on outside air humidity this method will get the clothes pretty dry after a few hours ( 5 hours = 350 w) It works for us. 👍👍
I am from Germany and I grew up airing rooms several times a day, especially in the morning after getting up. I am shocked to see that people in England don’t seem to be doing this. By the way, I never had mould in my German home 🙂 After airing we always had a room temperature of at least 19 degrees Celsius. Washing is put in a washing cellar or hung up outside whatever the weather.
Have a small amount of mould under a worktop in a semi-commercial building. I can only think the external RWP guttering and sink outlets are not really best placed, they are not broken, overflowing or above DPC but still in a one brick and render thick building are not really working. Also had a new 1980s built flat constantly had condensation and mould in window frame corners, basically was before thermal break lintels and reveals and trickle vents in window frames came in, which would improve
Excellent article Roger and my thoughts exactly. I actually had an argument with my wife about this last week when I pointed out that the majority of times the cause of indoor mould is lifestyle choices. She is one of those who takes the news reports as gospel, so it therefore must be the local authorities’ fault. I reminded her that in some of the first homes we lived in together, we had exactly the same problem through ignorance. In our first home we used to use our tumble dryer unvented and wonder why there was black mould forming around it. We learned the hard way how not to do it. I honestly think they should be teaching stuff like this in schools. God knows what it must be like for immigrants settling here from hot countries with no experience of the British climate whatsoever.
Have you ever thought of becoming an MP and bringing some common sense to Government. I was an Architectural Technologist in Local Authorities and Housing Associations for more than 30 years. I failed to make this point; not only to tenants but also to the organisation’s hierarchy. The lesson is that you cannot help those who will not listen to informed advise. 🤷♂
I have been banging on about mould for years. As a landlord and builder, I constantly explain the basics: mould is man made, ventilation will prevent it, ventilation is good for you as well as the house. I lived in my house for 8 year and had no mould. Within 6 months the tenants rang me to say that there was mould. I went round and the wall was BLACK. I was livid and so repeated my explanation. It’s a myth that when you open the window all the warm air goes straight out. Cool air comes in. Anyone who tried to smoke out of a window as a kid can tell you that: they smoke comes right back into the house on the rising thermals from the pressure outside. This is also why we put radiators under windows. One area I do struggle to help (people is north facing corners. They can be extremely cold and I do understand that ventilation is an issue there, so I try to find a way to heat it and avoid that cold bridging. I fear that the poor little boy’s death will lead to falsely proven legislation, rather than National education.
Hi Roger I’m a joiner and was lucky enough to be taught by tradesman like yourself many years ago, Another great article . I’m qualified in structural waterproofing and I explain it to people with example of the droplets on a glass of coke or beer, even on a hot day moisture will cool and turn back to droplets on the cool glass and what is known as “dew point ” If the surface is cold enough and in property this is normally external walls in winter dew point occurs then mould grows
The cause of the mold in public housing in this country is caused by the inferior building standards in the UK with the lack of proper extraction of moisture by inadequate extractor fans that are installed and lack of aeration through the walls to the outside. The only way to stop in in these installations is to stop breathing, not cook any food or even just not live in these places at all.
If you’re measuring the humidity levels. it’s also worth learning about relative humidity. Cold air holds less moisture than warmer air, so air with a relative humidity of 60% at 17C has a lot less moisture in it than it at 23C with the same percentage RH. If you like the house warmer than average, but also have a high relative humidity, then you’re going to have a problem with condensation.
Back in the very early 80s the sister in law lived in HM Armed Forces housing. Black mould was rampant. Storage heating. ( kin useless) eventually they were allowed to unboard the fireplace, get the chimney swept and put a grate in. Nice cosy room. Mould gone very quickly afterwards. That’s over 40 years ago.
We rented a 30m2 ground floor flat in London, which actually had slugs which wandered about at night, but otherwise was comfortable and nicely done. However I could feel the humidity problem, so I built my own mini heat-exchange ventilation system which I put through the letterbox. Since we were renting, it was the only available non-destructive route to the outside. It ran on a couple of 12V fans the whole time we lived there. We put back in the original letterbox when we left. I’ve been in so many London flats that are a humidity nightmare, though, even if they haven’t got mould yet. It really needs a lot more attention.
This is an outstanding article. A brilliant and insightful explanation of what is as you say, as very simple problem. Houses used to be much draughtier than they are now, which provided continuous air exchange, and open fires and kitchen cooking ranges would draw in fresh air, as well as warming the fabric of the building. These things both helped to reduce mould without the homeowner needing to do anything specific.
Valid points but small flats have less air to saturate and mould requires spores so once anywhere then it is more likely to occur. Landlords need more focus in this article and should put in better extractors not bathroom ones in these kitchens and ensure there are no cold spots. As well as properly sealed double glazing instead of leaky mould breeding units with blocked vents. Advice on opening windows or getting an ac unit upon tennancy might help too.
As a retired housing association surveyor I agree with everything you say. It is very hard to convince occupants that much of the problem is of their own making. People cannot afford to heat properties adequately and are unwilling to ventilate. Your article should be compulsory viewing for all tenants & journalists. Well done.
Had this problem with tenants in our basement flat when we decided to rent it out. Lived there for 8 years ourselves and never had an issue with mould. Then had some foreign tenants moved in they blocked up vents in the bedrooms and turned off the bathroom vent because it was a bit cold. And they had washing drying on radiators instead of using the tumble dryer I had given them. They had mould within weeks. Bizarre thing is they never cleaned the mould they just jumped on the telephone when it was too late and I ended up having to pay for redecorating the walls in the bad spots. So usual story tenants ignorance costing landlord money.
I air my rooms out all the time, even when its cold. I also use a dehumidifier and an extractor fan in the bathroom and kitchen. Once or twice during the winter, a few spekcs of mould crops up in the corner of the ceilng. I bleach it, and then its gone. As an owner occupier, I take care of my house. Ok, if your roof and gutters are leaking and there is damp from outside, then maybe its your landlords fault. But alot of people create mould problems because they never open the windows, and dry clothes indoors without opening the windows.
Some years back, we gutted our bathroom and installed a new one. The bathroom has an extractor fan and a window that that is often opened. It has always been regularly cleaned yet when the bath was removed, there was mould on the wall that we were completely unaware of. The bath also incorporated the shower and it appears that the seal around the bath was not as effective as it seemed thanks to the flexible nature of the bath itself. It was one of these plastic / fibre glass baths and when someone stood in it to have a shower, the seal around the bath must have been slightly “prised open,” as it were, by the weight of the person and moisture / water flowed down behind the bath out of sight, creating the mould (a good case for the bringing back the old cast iron baths). We didn’t replace the bath; we have a self contained shower cubicle instead and have no mould whatsoever now. So, it’s not simply a ventilation issue, you also have to make sure there is no seepage of moisture or water, whether the source is inside or from the outside of the house.
moisture is always building up in the coldest spot! Over here in Germany we have the same discussions with people. Good to see that it is a “global problem”. You got to get the moisture out and heat up the room enough. Too much ventilation with fresh air will also result in mold…. because you cool down the walls too much and do not give them the chance to heat up again. It is the right amount of fresh air that counts. If air is cold then it can hold less moisture and it will settle down on the coldest spots. A lot of people are also choosing the easiest and cheapest way to modernise and that´s windows… they build in double or even triple glazing windows but do not modernise insulation on the walls. now the window isn´t the coldest spot anymore, so the moisture will settle on walls and that is where the mold will be. they can ventilate as much as they want mold will always be somewhere as long as they do not modernise their walls and insulation and most of the times they just do not have the money for that! The right amount of heating and the right amount of ventilation is critical. there are “calcium chloride” stones that regulate moisture and they are not that expensive, it can help keep the moisture out of the walls. If you had condesation at a window in the morning in winter and you get new windows and it isn´t there anymore, that is bad, cause on the glass there won´t be mold but now you moved the cold spot to the wall…. congrats you will get mold…
Our rented house is just cavity walls and the outside walls are freezing in the winter, takes the bathroom 2 days to fully dry with the window open during the day. Towel rail radiator doesn’t do anything to warm the bathroom up, atleast that would probably help if it was able to stay warm so the moisture could just be sucked out by the extraction fan
The thing that had me ‘discussing’ mould with a landlord was the fact that he’d put the fan in the bathroom ceiling, this meant it was blowing the warmest air out of the roof and dragging cold moist air in from outside. He tried to claim it wasn’t but did concede that the fan wasn’t pulling a vacuum. I guess I’ll have to look at the running costs of a de-humidifier.
Great factual presentation (especially the woman in her undies) that basically explains that we live in an eco-system and need to balance, heat, air and water. If you just think of warmth or just think of bills (£) you’ll suffer from the mould which will love the eco-system YOU have created for it. Best of all was the formidable punchline about mistreating the youth – a lot of truth in that.
Use dehumidifier. It consumes about 400W of electricity and all this consumed energy goes to heating your house. So you spend less money on other heating sources. I live in Montenegro and the winter here is warm and we have a lot of raining days. Before we bought dehumidifier we had large quantities of mold on the walls. And every surface in the room was kind of wet on touch. And after dehumidifier and killing mold with special liquids, there is almost none of it anymore. Maybe every 3 weeks there are small dots of mold appear on the wall, and I just spray it and that’s it. So, regulate your humidity levels.
I never had mould in my house but noticed the humidity was constantly above 70%, we have 1 Yr old twins so opening windows with them around isn’t that convenient but I did when it was possible and the humidity stayed high. The simple answer was to wipe down the windows a few mornings a week and to use a window vac. Humidity was down in low 60s within a week and now hovers around 50-55%. With little condensation on windows. We also keep doors closed to stop air circulating from warmer parts of the house to the colder parts. It really does just take some commonsense.
Beibgva chippy I have my bettef half, you must have some ventilation coming from somewhere. So as we know double glazed windows have vent for this purpose, so even When it’s cold I have 4 open around the house. Apart from condensation on the windows early mornings, once sqeegeed & wiped they’re fine but no mold! Just use a mild spray of 6 parts water to 1 part bleach to treat odd spots & bathrooms. Bang on. Nice article.