Mould in houses

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pwa
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Re: Mould in houses

Post by pwa »

peetee wrote: 26 Nov 2022, 8:19am In my experience a great deal of damp in the house is not transferred through the structure by poor insulation or weatherproofing, rather it is generated by the occupants. Ignorance of this was the dodgy builders ‘bread and butter’ back in the day as many a naive house owner was conned into forking out for DPC, roof tile or cavity work purely on the grounds of excess condensation.
When my daughter returned home there became three occupants at my property and the condensation levels increased appreciably. We have a strict regime with regard to showers and drying clothes indoors. When this is not observed the results are very obvious; the dehumidifier is on constantly and the house feels damp and, crucially, colder than it actually is. The dehumidifier really is a valuable piece of kit in such a house. While windows can be opened to ‘flush out’ damp air they are very small and the path of that air through the house never changes so large areas of the property do not benefit. The dehumidifier however can be put anywhere and I have used it in grotty corners along with a fan heater and it is effective. It’s all rather an expensive business though and undoubtedly I’d have less to do if certain residents would be a bit more thorough at obeying the rules!
As you say, we create a lot of the moisture ourselves. Even the act of breathing does it. But the condensation that results from this tends to be concentrated on cold spots such as windows or cold corners of walls. In most homes that is trivial and can be dealt with by occasionall wiping with something mould doesn't like. But extreme cases need properly sorting with more insulation or whatever. In your own home you do what you have to over the years to get things right, but renters have to ask someone else to do it.
thirdcrank
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Re: Mould in houses

Post by thirdcrank »

My recollection from O Level science 60+ years ago is the carbon dioxide (CO2) isn't poisonous. IIRC it's inert and being in a room full of the stuff would suffocate you ie lack of oxygen but it would't poison you.

Still on O level, burning hydrocarbons produces water, demonstrated by holding a (glass) flask of cold water over a gas flame when the flask will be briefly covered with condensation till the flame heats it. Also, the water seen tricking from the exhausts of internal combustion engines when the vehicle is started from cold. I think that "cooking with gas" is one cause of condensation in houses, in addition to things like boiling food.

Carbon monoxide CO is the killer. It used to be a significant constituent of town gas, which everybody knew was poisonous, even if they hadn't done O level. It's also a product of the partial/incomplete burning of hydrocarbons such as natural gas and petroleum products. Again, most people know vehicle exhaust fumes are a killer. Perhaps the dangers from cooking and heating with natural gas with inadequate ventilation were not so readily understood by many people

The O level science is that carbon monoxide readily combines with haemoglobin to form carboxyhaemoglobin (?) preventing the blood from transporting oxygen around the body
Psamathe
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Re: Mould in houses

Post by Psamathe »

thirdcrank wrote: 26 Nov 2022, 1:03pm My recollection from O Level science 60+ years ago is the carbon dioxide (CO2) isn't poisonous. IIRC it's inert and being in a room full of the stuff would suffocate you ie lack of oxygen but it would't poison you.
...
From my scuba diving days I do remember that it's CO2 in your blood that makes you want to breath not lack of oxygen. More CO2, more you want to take a breath. Reason I remember is that before leaving surface to dive down without aqualung (i.e. holding your breath) you should not take loads of deep breaths as this flushes the CO2 out of your blood stream and doesn't add much oxygen so you risk not getting enough stimulus to breath (not much CO2) but do have low oxygen and risk is you can pass-out from lack of oxygen without a strong desire to take a breath! (at least that is what we were taught). i.e. your body is calibrated to the normal balance of O2/CO2 and lots of deep breaths changes that normal balance to low CO2 and normal O2.
thirdcrank wrote: 26 Nov 2022, 1:03pm ...
Still on O level, burning hydrocarbons produces water, demonstrated by holding a (glass) flask of cold water over a gas flame when the flask will be briefly covered with condensation till the flame heats it. Also, the water seen tricking from the exhausts of internal combustion engines when the vehicle is started from cold. I think that "cooking with gas" is one cause of condensation in houses, in addition to things like boiling food.
...
I was always told paraffin heaters were terrible for adding water to the atmosphere. When I lived in France I used paraffin heaters a lot (all the supermarkets sold massive paraffin containers). Never noticed a problem but I was living an a watermill with the river running through the house so probably already pretty humid. nb the paraffin heaters were pretty "hi-tech" and needed electricity for fans, gas monitors, thermostats, auto-ignition, etc.

Ian
thirdcrank
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Re: Mould in houses

Post by thirdcrank »

In the context of various forms of damp in houses, perhaps the best approach to any sort of underwater activity is "don't try this at home" unless you have a swimming pool, of course.
axel_knutt
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Re: Mould in houses

Post by axel_knutt »

There are small amounts of mould in the corner of my kitchen, but they never get any worse, so they're not a problem. The main bugbear is the shower curtains, it doesn't wash out, so they're perpetually black. Opening a window works, at a price, but an extractor fan doesn't touch it. I've just bought a new pair, so as use the shower less now I'm not cycling every day, I keep meaning to try leaving the bathroom door open so that the humidity gets diluted by dispersing into a 24 times larger volume of air, it just depends how humid the rest of the house is already.

"The United States Environmental Protection Agency (EPA) currently recommends that relative humidity be maintained below 60%, ideally between 30% to 50%, to inhibit mould growth"
peetee wrote: 26 Nov 2022, 8:19am....cavity work purely on the grounds of excess condensation
Cavity wall insulation can be the cause of mould. In exposed locations where driving rain saturates the outer leaf, the cavity prevents transfer to the inner leaf as long as it's not bridged with insulation.
thirdcrank wrote: 26 Nov 2022, 1:03pmStill on O level, burning hydrocarbons produces water, demonstrated by holding a (glass) flask of cold water over a gas flame when the flask will be briefly covered with condensation till the flame heats it.
That's why condensing boilers work, they condense the water vapour in the flue gas so you recover the latent heat of vapourisation. The LH/V of water is huge: 2.26MJ/kg
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.”
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francovendee
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Re: Mould in houses

Post by francovendee »

Psamathe wrote: 26 Nov 2022, 1:24pm
thirdcrank wrote: 26 Nov 2022, 1:03pm My recollection from O Level science 60+ years ago is the carbon dioxide (CO2) isn't poisonous. IIRC it's inert and being in a room full of the stuff would suffocate you ie lack of oxygen but it would't poison you.
...
From my scuba diving days I do remember that it's CO2 in your blood that makes you want to breath not lack of oxygen. More CO2, more you want to take a breath. Reason I remember is that before leaving surface to dive down without aqualung (i.e. holding your breath) you should not take loads of deep breaths as this flushes the CO2 out of your blood stream and doesn't add much oxygen so you risk not getting enough stimulus to breath (not much CO2) but do have low oxygen and risk is you can pass-out from lack of oxygen without a strong desire to take a breath! (at least that is what we were taught). i.e. your body is calibrated to the normal balance of O2/CO2 and lots of deep breaths changes that normal balance to low CO2 and normal O2.
thirdcrank wrote: 26 Nov 2022, 1:03pm ...
Still on O level, burning hydrocarbons produces water, demonstrated by holding a (glass) flask of cold water over a gas flame when the flask will be briefly covered with condensation till the flame heats it. Also, the water seen tricking from the exhausts of internal combustion engines when the vehicle is started from cold. I think that "cooking with gas" is one cause of condensation in houses, in addition to things like boiling food.
...
I was always told paraffin heaters were terrible for adding water to the atmosphere. When I lived in France I used paraffin heaters a lot (all the supermarkets sold massive paraffin containers). Never noticed a problem but I was living an a watermill with the river running through the house so probably already pretty humid. nb the paraffin heaters were pretty "hi-tech" and needed electricity for fans, gas monitors, thermostats, auto-ignition, etc.

Ian
In the 60's a friend, his wife and their young son lived in a basement flat in Ladbroke Grove London. Their only form of heat was an Aladin paraffin heater. The walls ran with moisture and living there must have been thoroughly unpleasant. No surprise their son had and still has chest problems.
In those days it was the cheapest form of heating but must have harmed many people.
At the time fires caused by paraffin heaters were often reported.
Tiberius
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Re: Mould in houses

Post by Tiberius »

I was expecting one of you knowledgable bods to post up something like....'I bought this stuff, sprayed it on the mould, it went away and never came back'...I would OBVIOUSLY then expect the knowledgable bod to post up a link to said jollop - preferably to a cheap Black Friday deal on Amazon.

Two full pages and nothing yet.

Life can be one disappointment after another eh??..... :mrgreen:
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al_yrpal
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Re: Mould in houses

Post by al_yrpal »

I am presently damp proofing our annexe a separate building to our house, which has areas of rising damp. I am inserting Dryrods in the base of of the walls to form a damp proof course. There is a bit of mould at the base of the walls and I have bought this stuff to eliminate the mould but havent used it yet...

https://www.amazon.co.uk/dp/B08P5ZDSW3? ... b_ap_share

Al
Reuse, recycle, thus do your bit to save the planet.... Get stuff at auctions, Dump, Charity Shops, Facebook Marketplace, Ebay, Car Boots. Choose an Old House, and a Banger ..... And cycle as often as you can......
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Mick F
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Re: Mould in houses

Post by Mick F »

Tiberius wrote: 27 Nov 2022, 8:34am I was expecting one of you knowledgable bods to post up something like....'I bought this stuff, sprayed it on the mould, it went away and never came back'...I would OBVIOUSLY then expect the knowledgable bod to post up a link to said jollop - preferably to a cheap Black Friday deal on Amazon.

Two full pages and nothing yet.
This is what I bought.
https://www.screwfix.com/p/no-nonsense- ... 1ltr/31686

Sprayed it on and left it a while, then set about scrubbing. Gasping for breath too! Dead smelly and gaseous. Better with the window open!

Two applications in our mouldy corner, then I found another patch behind the dressing table, so that got done too.

As for "never coming back", after cleaning the wall to within an inch of its life, I redecorated and made sure the furniture wasn't too close to the walls. Now I know about this issue, I will be keeping an eye on it in future, so it won't come back. Prevention is better than cure.
Mick F. Cornwall
PH
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Re: Mould in houses

Post by PH »

Psamathe wrote: 26 Nov 2022, 1:24pm I was always told paraffin heaters were terrible for adding water to the atmosphere. When I lived in France I used paraffin heaters a lot (all the supermarkets sold massive paraffin containers). Never noticed a problem but I was living an a watermill with the river running through the house so probably already pretty humid. nb the paraffin heaters were pretty "hi-tech" and needed electricity for fans, gas monitors, thermostats, auto-ignition, etc.
Ian
I had a hi-tech paraffin heater in a workshop 20+ years ago, a Japanese made Zibro, a completely different thing from the smelly paraffin wick heater my Granny had. We still needed to keep the space well ventilated to avoid condensation, I don't think that's avoidable burning any fuel in any heater without a flue.
At home I use a dehumidifier, absolutely brilliant piece of kit, not even a sophisticated model, less than £100 four years ago. Paid for itself several times over, use less heat, hardly ever any condensation on the windows (I used to squeegee them dry every morning), laundry dries in half the time. Wish I'd bought one years before, TBH I'd never heard of one till shortly before I bought mine, when did they become commonplace?
Tiberius
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Re: Mould in houses

Post by Tiberius »

Al and Mick...

Many thanks for you input -Appreciated.
Biospace
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Re: Mould in houses

Post by Biospace »

horizon wrote: 22 Nov 2022, 3:59pm The worst thing to happen to UK homes was double glazing and plastic windows.
Well, sort of. Wasting heat to the outside is inefficient use of whatever fuel (even stored solar) is used to keep things warm. But yes, in a damp place, those sheets of cold surface were a good indication of how damp the air was. Trying to feel warm in a damp house (more likely with double glazing) is a very expensive process.

{quote] Houses need to breathe.
[/quote]

Building regulations homogenise and insulation levels increase, but we should bear in mind that our climate is a good bit damper than for most of the rest of Europe. Damp air is in ine sense like radiant heat - invisible and not always fully understood for the huge effect it has on how comfortable we feel, irrespective of that temperature which we constantly reference.

A financially wealthy fellow built a house in rural Scotland a few years ago, using the very latest of everything. Its internal climate is regulated by computer using hidden ducting with the beautiful outdoor air drawn through filters and warmed by the exiting air.

Even with massive amounts of insulation it wasn't to Passivhaus standards, underfoor heating and a log stove offer some old-fashioned comfort and for when it's sub-zero outside - which isn't so often in the far west of Scotland. The vacuum cleaner is no more than a glorified pipe which plugs into a(nother) pipe network hidden within the walls, attached to an air pump to the outside.

We stayed there one winter and with the stove warming a very chilly-feeling but perfectly evenly distributed 18.9C one wet day (it was around 9C, we'd been on a long walk), a steady drip of liquid came from under where we'd placed our wine. The first thought was that the bottle was leaking, the second that one of my terriers had somehow cocked his leg unusually high.

It was neither. A largish piece of stone was sufficiently cooler than the stove-warmed, moisture-laden air that its surface was running wet and dripping, every couple of seconds. I've heard similar stories where various pieces of electronic equipment have been damaged by this sort of drip - clearly roaring fires and open windows (as a Lancastrian grandfather described a visit to Yorkshire back in the 50s) aren't so commonplace today.
ANTONISH
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Re: Mould in houses

Post by ANTONISH »

axel_knutt wrote: 26 Nov 2022, 3:05pm There are small amounts of mould in the corner of my kitchen, but they never get any worse, so they're not a problem. The main bugbear is the shower curtains, it doesn't wash out, so they're perpetually black. Opening a window works, at a price, but an extractor fan doesn't touch it. I've just bought a new pair, so as use the shower less now I'm not cycling every day, I keep meaning to try leaving the bathroom door open so that the humidity gets diluted by dispersing into a 24 times larger volume of air, it just depends how humid the rest of the house is already.
I had a similar problem - fitting an air brick low down in the bathroom wall stopped it.
Stevek76
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Re: Mould in houses

Post by Stevek76 »

I'd say ditch the shower curtain altogether for some sort of glass door/barrier. Much easier to wipe down, quite hard for mould to grow on.
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simonineaston
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Re: Mould in houses

Post by simonineaston »

Think ourselves lucky. For most of human history, we lived in pools of mud.
S
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