Damp and mould 101

slhqoue

Hi there,

We have black patches of what I think is damp appearing on the inside of our attic room sloping wall, as well as patches of white furry mould and occasional small spots of black appearing on the inside of our bay window with shutters in our living room. Pictures attached.

We have been treating the attic room with watered down vingegar - in the living room we've been wiping off the white furry mould with a damp cloth.

We'd obviously like to solve both issues - the living room issue has gotten worth since getting shutters installed (pictured), while the attic room issue has been long running but has also been worse this year.

These issues only rear themselves in winter hence it is almost certainly linked to the lack of turning on the heating! We're also trying to open the windows to allow air in although obviously this will become increasingly difficult as it gets colder to leave them open for any amount of time.

I know this is probably quite a common issue but any general advice as to how to deal with these two problems would be greatly appreciated!

plumb1_2

Lack of insulation and air flow.

tacpot12

There are a number of things you can do: 

• Get the roof checked to ensure that there is no water getting into the space behind. You should review the level of insulation while you are there and also check whether it is still attached to the walls. Consider installing additional airvents into the attic room. Even a small vent can promote enough airflow to dry the room substantially. You can get vents with adjustable shutters that would allow you to reduce the airflow down the minimum that solves the problem.  

• Consider whether you have enough forced extraction in the rooms that generate the most moist air, i.e. the kitchen and bathrooms. I've always had problems with mold in bathrooms until I've installed a humidity controlled fan - a fan that will run as long as is necessary to remove moist air. You could do the same in the kitchen if you turn any cooker hood off the moment you stop cooking.

• If you have a tumble dryer that isn't vented, you should consider replacing it, as any moist air from the dryer could be contributing to the problem.   

• Consider installing a Postive Input Ventilation System. I think one of these could work very well for you as they force air to flow towards the windows (which need to have trickle vents fitted). This means it would help to move air through the shutters and this should pick up all the dampness and move it outside asap. It would also work well with any new vents installed in the attic room, providing the intake and output of the PIV are located as far away from the vents as possible, ideally the output of the PIC should feed into the lower floor. Rectangular ducting is available to make this unobtrusive.  
  

• Consider turning the heating up a degree or two. If the other solutions haven't worked, this might be necessary, but it should be your last resort.   

FreeBear

slhqoue said: We have been treating the attic room with watered down vingegar - in the living room we've been wiping off the white furry mould with a damp cloth.

You would be better off using a dilute bleach solution. Vinegar will just etch in to the surface of the plaster and be neutralised before it has a chance to do anything.

Run a dehumidifier in the affected rooms to help to reduce condensation during the winter months.

calleyw

FreeBear said:

You would be better off using a dilute bleach solution.

Well these websites disagree with you on the use of bleach on mould

https://lookmold.com/removal/bleach-kill-mold

https://mastertechmold.com/2020/08/why-you-should-never-bleach-mold/

https://www.moldprotips.com/what-does-bleach-do-to-mold/

https://www.epa.gov/mold/should-i-use-bleach-clean-mold

And some webesites seem to suggest that if you do use bleach only on non porous surfaces.  A ceiling is porous

https://shamrockrestore.com/does-bleach-kill-mold-a-risky-common-cleaner/

chris_n

In your living room you have probably made it worse with the shutters because you have reduced how much condenses on the windows, next coldest place is the wall so it condenses there. Your air clearly contains too much water, whether that is from lack of extraction from cooking / bathing or insufficient general ventilation these are the first things to look at. Next is heating, warm air can hold more water than cold air, if you heat the air then let everything cool too much the water has to come out of the air and will always condense at the coldest points.

Apodemus

calleyw said:

FreeBear said:

You would be better off using a dilute bleach solution.

Well these websites disagree with you on the use of bleach on mould

https://lookmold.com/removal/bleach-kill-mold

https://mastertechmold.com/2020/08/why-you-should-never-bleach-mold/

https://www.moldprotips.com/what-does-bleach-do-to-mold/

https://www.epa.gov/mold/should-i-use-bleach-clean-mold

And some webesites seem to suggest that if you do use bleach only on non porous surfaces.  A ceiling is porous

https://shamrockrestore.com/does-bleach-kill-mold-a-risky-common-cleaner/

Hmmm...  I gave up on your first link when it was trying to tell me that mould doesn't grow on plaster...

FreeBear

Apodemus said:

calleyw said:

FreeBear said:

You would be better off using a dilute bleach solution.

Well these websites disagree with you on the use of bleach on mould

https://lookmold.com/removal/bleach-kill-mold

https://mastertechmold.com/2020/08/why-you-should-never-bleach-mold/

https://www.moldprotips.com/what-does-bleach-do-to-mold/

https://www.epa.gov/mold/should-i-use-bleach-clean-mold

And some webesites seem to suggest that if you do use bleach only on non porous surfaces.  A ceiling is porous

https://shamrockrestore.com/does-bleach-kill-mold-a-risky-common-cleaner/

Hmmm...  I gave up on your first link when it was trying to tell me that mould doesn't grow on plaster...

I had a quick look at those links too. The first three are sites selling their own services & fixes, so need to be taken with a good dose of salt. The EPA just says bleach is a biocide and warns against mixing with other cleaning chemicals.

I have used a dilute bleach solution on plaster walls that had spots of black mold - It was an effective treatment, and whilst it may not have killed all the mold, I didn't have it return. Also use bleach to clean black mold off some grout in the bathroom from time to time. Really can't be bothered to spend $$$ on "special" cures when a £1 bottle of Domestos will do the job.

Bendy_House

slhqoue said:

Hi there,

We have black patches of what I think is damp appearing on the inside of our attic room sloping wall, as well as patches of white furry mould and occasional small spots of black appearing on the inside of our bay window with shutters in our living room. Pictures attached.

We have been treating the attic room with watered down vingegar - in the living room we've been wiping off the white furry mould with a damp cloth.

We'd obviously like to solve both issues - the living room issue has gotten worth since getting shutters installed (pictured), while the attic room issue has been long running but has also been worse this year.

These issues only rear themselves in winter hence it is almost certainly linked to the lack of turning on the heating! We're also trying to open the windows to allow air in although obviously this will become increasingly difficult as it gets colder to leave them open for any amount of time.

I know this is probably quite a common issue but any general advice as to how to deal with these two problems would be greatly appreciated!

What is the attic room used for - a bedroom, or what? 
Nice shutters! As mentioned before, tho', they probably exacerbate the problem by reducing the air flow around there, and air flow is what you want.

That sloping ceiling is pretty evenly mouldy and discoloured, so I'd hazard that it IS condensation forming on it, and not due to a leak from the outside. That amount of damp cond on a wall suggests you are either producing stupid amounts of moisture in your home - unlikely - or else that ceiling is stone cold. Ie, it is nicely ventilated on the other - roof - side (good news), but also has next to zero insulation (not good). So, the nice air flow on the other side of that ceiling is really cooling it down, and making it a magnet for cond in your house. The best single solution would be, I think, to add a layer of insulation to the inside. Insulated plasterboard can simple be glued and screwed on to that ceiling.

Other than that, whenever the room is not being used, turn the heating right down, and crack open some windows to ventilate it as much as possible. If it's a bedroom, try to keep it ventilated all night - snuggle under a duvet to keep warm.

For the living room, I can't see the affected parts, but the same applies - when not in use (,eg during the day and overnight), heating right down low (~10oC), and windows on vent. Only close the windows and turn up the heat when you are actually there.