problem with black mould building up walls, ceiling

trixyben

I have a house that I rent out and im having a problem with black mould around the top a windows and random patches on the ceilings, up stairs, i had window vents put in all up stairs windows to help air ventilation but to no avail, anything that is up against one o the bedroom walls ater a while will start to grow mildew on it...

This has been a problem or a while now and want to get this sorted i thought maybe cavity insulation was maybe needing reilled but had this checked and its OK..

Has anyone had problem with similiar and how did you solve the problem?

cheers

budgemook

i had this in a bathroom of a place i used to rent and again in the place i rent now. Tried a few things, cleaning it off and painting with anti-mould/plasticy paint, installing extraction fans, keeping windows open. Nothing worked for me. After a lot of research I found that most people think I need a dehumidifier. I moved out of the last place because of it and may do the same from this place. Shame though, I like this place.

Tiles are a good way to avoid it but obviously only in a bathroom.

trixyben

budgemook wrote: »

i had this in a bathroom of a place i used to rent and again in the place i rent now. Tried a few things, cleaning it off and painting with anti-mould/plasticy paint, installing extraction fans, keeping windows open. Nothing worked for me. After a lot of research I found that most people think I need a dehumidifier. I moved out of the last place because of it and may do the same from this place. Shame though, I like this place.

Tiles are a good way to avoid it but obviously only in a bathroom.

tried those things also put an extractor in the bathroom but still no good, advised to leave windows open during day were possible still no good...dont no how to beat this one!

slimjimmc

Trixyben, try cleaning the affected areas with a ready-made fungicide or a dilute bleach solution (5 water:1 bleach) to kill off the mould and spores. That at least should improve things for a while until the source of the dampness is found.

brendankelly

Dampness is where moisture seeps from the outside through the wall into your room. If you look in you attic over the dark spot in your ceiling you will find a wet spot. If the cavity insulation is installed badly there will be air pockets or if you like a hole and water will cross over this bridge into the inside wall. There is no way to check cavity insulation.

breezy1985

had the same problem in a flat the only real fix is better insulation

CBYR1983

Sounds like it's forming on cold, uninsulated external walls, that may be solid? Dry lining would probably help, if that's out of the question the anti mould paint like zinsser. Make sure there is insulation above the ceiling and no water ingress.

MicktheMan

trixyben wrote: »

I have a house that I rent out and im having a problem with black mould around the top a windows and random patches on the ceilings, up stairs, i had window vents put in all up stairs windows to help air ventilation but to no avail, anything that is up against one o the bedroom walls ater a while will start to grow mildew on it...

This has been a problem or a while now and want to get this sorted i thought maybe cavity insulation was maybe needing reilled but had this checked and its OK..

Has anyone had problem with similiar and how did you solve the problem?

cheers

Your problem is a combination of the following (which you may know already) :

- All rooms in the house not being sufficiently heated
- House not being sufficiently ventilated
- Possibly clothes being dried on radiators
- Windows not opened frequently and long enough
- Thermal bridging around the windows due to construction method
- Missing/compressed insulation in the attic directly above black mould on ceiling

Very often and in my experience, Landlords experience damp problems in their properties when certain tenants move in and then when the tenants are replaced with other tenants the damp problems subside. In your case this may not be the case but it is worth bearing this in mind.

The fundamental problem is that the longterm relative humidity is too high in the house. This is caused by not replacing moisture laden air with fresh dry air by a good ventilation strategy. Sort this out and you will eliminate or greatly mitigate your problem.

Btw, drylining (internal insulation) on its own will make the situation worse rather than better.

budgemook

MicktheMan wrote: »

Your problem is a combination of the following (which you may know already) :

- All rooms in the house not being sufficiently heated
- House not being sufficiently ventilated
- Possibly clothes being dried on radiators
- Windows not opened frequently and long enough
- Thermal bridging around the windows due to construction method
- Missing/compressed insulation in the attic directly above black mould on ceiling

Very often and in my experience, Landlords experience damp problems in their properties when certain tenants move in and then when the tenants are replaced with other tenants the damp problems subside. In your case this may not be the case but it is worth bearing this in mind.

The fundamental problem is that the longterm relative humidity is too high in the house. This is caused by not replacing moisture laden air with fresh dry air by a good ventilation strategy. Sort this out and you will eliminate or greatly mitigate your problem.

Btw, drylining (internal insulation) on its own will make the situation worse rather than better.

This is interesting.

My bathroom is the room that get's the mould, and it's mainly around the upper wall and roof where the bath is. I assumed it was because of all the moisture in that area - The electric shower is in the bath.

However, the window is beside the bath and even when it's shut plenty of air gets in. It's a cold house and the windows all have draughts so I don't think it's a ventilation problem.

However, like I said it's a cold house. There are some storage heaters downstairs but in the bathroom upstairs there is only a pretty crap blow heater on the wall that gets turned on just before we shower in the morning - Is it likely that it's mouldy because it's so cold?

I haven't been up to the attic but the mould is worse on the upper wall than it is on the roof.

I'm going to try cleaning it with bleach as already posted but if the cold is the problem I need to think of something long term.

MicktheMan

budgemook wrote: »

However, like I said it's a cold house. There are some storage heaters downstairs but in the bathroom upstairs there is only a pretty crap blow heater on the wall that gets turned on just before we shower in the morning - Is it likely that it's mouldy because it's so cold?

Yes, the internal temperature, in this case, is an important factor. Relative humidity (RH) of air is highly temperature dependent. That is, outside air at 0 degrees generally has a rh of 90%. This very same air when warmed to room temperature could have a rh of 40% (i.e. much dryer air). So when we ventilate a sufficiently heated house (or room) with cold outside air, the house air rh will be low and problems such as mould growth are eliminated or mitigated. On the other hand, if the house is under heated then this drying of the air effect is significantly reduced.
Hope I explained this reasonably clearly.

budgemook

MicktheMan wrote: »

Yes, the internal temperature, in this case, is an important factor. Relative humidity (RH) of air is highly temperature dependent. That is, outside air at 0 degrees generally has a rh of 90%. This very same air when warmed to room temperature could have a rh of 40% (i.e. much dryer air). So when we ventilate a sufficiently heated house (or room) with cold outside air, the house air rh will be low and problems such as mould growth are eliminated or mitigated. On the other hand, if the house is under heated then this drying of the air effect is significantly reduced.
Hope I explained this reasonably clearly.

Yeah that makes sense. Now that leaves me with the question how the f**k am I going to keep the room warm?

Thanks for the reply.

brendankelly

I have worked on hundreds of houses and I never saw a damp spot on a ceiling that did not have a leak above it in the felt/roof. It is the same for the walls. If the outside plaster is cracked you will have a damp wall inside unless it is a cavity wall that is vented. Water tanks are often placed above bathrooms and condensation will form on the outside of tanks and pipes that becomes water when it hits the plasterboard.

MicktheMan

brendankelly wrote: »

I have worked on hundreds of houses and I never saw a damp spot on a ceiling that did not have a leak above it in the felt/roof. It is the same for the walls. If the outside plaster is cracked you will have a damp wall inside unless it is a cavity wall that is vented. Water tanks are often placed above bathrooms and condensation will form on the outside of tanks and pipes that becomes water when it hits the plasterboard.

I also have surveyed many properties and rarely find that dampness is caused by failures in the roof or walls. Rather, it is caused by excessively high rh, poor ventilation, insufficient heating etc. Of course, this is more difficult to prove or point to than a leaking roof but can be done.

I doubt very much that the OP has leaks around her windows causing the dampness and mould!
The longterm effects that elevated rh has on a building is not well understood in this country by designers, builders and householders.

weeeeeeeezy

Sorry to butt in on op but I also have a question. We had an issue with damp on walls in a place were renting. Landlord fixed it by putting insulated plasterboard and replastering the wall. All was grand until winter set in and were finding that we are getting what I can only describe as condensation on the floor of the room but walls are fine. The landlord keeps telling it's from drying clothes in the room. I never dry clothes in the room with this issue cos it's the bedroom. Any suggestions about the wet floor? We're ground floor apt.

Thanks!

MicktheMan

weeeeeeeezy wrote: »

Sorry to butt in on op but I also have a question. We had an issue with damp on walls in a place were renting. Landlord fixed it by putting insulated plasterboard and replastering the wall. All was grand until winter set in and were finding that we are getting what I can only describe as condensation on the floor of the room but walls are fine. The landlord keeps telling it's from drying clothes in the room. I never dry clothes in the room with this issue cos it's the bedroom. Any suggestions about the wet floor? We're ground floor apt.

Thanks!

Either one or both of the following is happening.

The floor is now the coldest part of the room (that you can see) and the moisture that was condensing on the walls previously is now condensing on the cold floor.

or

The insulated plasterboard has made the problem worse as you are now getting more condensation at the back of the insulated board (old wall surface is now colder) which is simply running down and accumulating on the floor.

The cause has not being addressed (i.e. ventilation/heating strategy)

karl tyrrell

you will never get rid of mould untill you core a six inch hole vent just below the celing has to be done the window vents are no good i have number of a man who does them.

brendankelly

A third option is that the moisture is still coming in through the wall, Flowing down the wall and seeping out on to the floor under the dry lining.

MicktheMan

As is clear from this discussion, there are many causes of damp in a building and it is important that damp probems are diagnosed on site by experienced professionals where all aspects of the building and its use can be taken into account, evaluated and solutions proposed.

yoshytoshy

MicktheMan wrote: »

Very often and in my experience, Landlords experience damp problems in their properties when certain tenants move in and then when the tenants are replaced with other tenants the damp problems subside. In your case this may not be the case but it is worth bearing this in mind.

This is definetly an issue ,have seen property destroyed by tenants who just won't open windows.

weeeeeeeezy

MicktheMan wrote: »

Either one or both of the following is happening.

The floor is now the coldest part of the room (that you can see) and the moisture that was condensing on the walls previously is now condensing on the cold floor.

or

The insulated plasterboard has made the problem worse as you are now getting more condensation at the back of the insulated board (old wall surface is now colder) which is simply running down and accumulating on the floor.

The cause has not being addressed (i.e. ventilation/heating strategy)

Thanks for reply. I kinda thought the floor being coldest part of the room was the problem. Floor is absolutely freezing (wooden floors) when you stand on it barefoot, even with socks on can feel cold.

Also could I just ask how much would not having the window open contribute to the whole problem? We're ground floor and work 9-5 mon-fri so can't leave window open during the day but I do open in morning before and in evening for a little while. But wil this make any difference if there is an insulation problem with the floor?

Thanks for all the replies!

MicktheMan

weeeeeeeezy wrote: »

Also could I just ask how much would not having the window open contribute to the whole problem? We're ground floor and work 9-5 mon-fri so can't leave window open during the day but I do open in morning before and in evening for a little while. But wil this make any difference if there is an insulation problem with the floor?

Thanks for all the replies!

You cook, wash & breath in your apartment and all these activities generate moisture (think 2-4 liters/day/person) which the air takes up. If this moist air is not replaced with dryer external air then you will get condensation & damp regardless.
Everything in the apartment takes up this moisture (think walls, ceiling, furniture, clothes, salt seller etc). Purge ventilation (opening windows full for a short time) while helping somewhat is not generally enough to allow all the moisture out. Therefore, you get moisture buildup & therefore problems. It would be better to leave youw windows open a crack for a much longer time (if possible) otherwise you will have to discuss with your landlord other ventilation/heating options.
Your problem appears to be excessive relative humidity and this needs to be addressed first.
Again, I stress that there is no real substitute to getting an experienced professional to survey the problem and advise.

weeeeeeeezy

Thanks Mick! The builder that did the wall came back and had a look said he did a moisture reading on one side of the floor and said it was on the high level of green but not into orange. Unfortunately I wasnt there at the time and couldn't tell him its opposite side of the room that has the really bad moisture like actual wet floor. He also said floor was cold to touch but that was cos the heating was off since earlier in the morning. The room and the floor are always cold even when heating is on.
Anyway got told again to stop drying clothes in the room and that would fix the problem have never dried clothes in the room btw.

Needless to say I'm really frustrated at the whole situation and am hoping to be out of there soon our lease up at end of Feb!

trixyben

was talking to a lad today said that i basically need more clean resh airlow through the house and a way is an air circulater which is placed in the attic and a fan in the landing ceiling which has temp and humidity sensors which comes on automatically, has anyone any experience of these units or can recommend one, cheers

brendankelly

If the dry lined wall is dry and the floor is wet at the bottom of that wall the moisture is coming out from the concealed wall and out under the drylining. This wetness is not condensation. You are lucky to be getting out because there are probably mushrooms growing behind the dry lining.

gsxr1

Everything Mick the Man said . +1

brendankelly

QSXR1. Since you are so sure that Mick The Man is correct perhaps you might explain to us what causes the dampness, mould etc in empty houses????. What is causing the dampness in the houses that were never lived in??. You will even find mould in half built houses with no windows. Is it condensation that is causing this????.

gsxr1

brendankelly wrote: »

QSXR1. Since you are so sure that Mick The Man is correct perhaps you might explain to us what causes the dampness, mould etc in empty houses????. What is causing the dampness in the houses that were never lived in??. You will even find mould in half built houses with no windows. Is it condensation that is causing this????.

http://en.wikipedia.org/wiki/Condensation

brendankelly

""Water vapor condenses into a liquid after making contact with the surface of a cold bottle.""
""Condensation commonly occurs when a vapor is cooled and/or compressed to its saturation limit when the molecular density in the gas phase reaches its maximal threshold""

You can use that theory in an occupied building but you have not answered my question.
What heats up the vapour in an empty building with no windows?????.

gsxr1

Why are you asking a question about an unoccupied building?

The OP lives in an occupied home.

If you are having problems with an unoccupied house why not start a thread on it. Im sure we can help you.;)

dathi

where do you think rain comes from there is moisture in external air that will be happy to condense on internal walls of unused buildings which are cold but this is not the op problem his problem as stated by other posters is a combination of poor ventilation , and lack of proper heating . the water vapour is condensing on the coldest spot

brendankelly

Moisture will only condense on a wall if the wall is colder than the temp of the room. If a wall is colder than the temp of a room then there is a problem with the wall. When condensation appears on a wall it means that there is what is called ""cold bridging"". This is where there is something that will carry the cold from the outside to the inside of the wall. In stone builds this was the ""Through Stones"" they became known as weeping stones by those that did not understand or by the builder that was trying to cover up for his bad workmanship. Moisture condensed on the Through Stone and flowed down the wall. ""Weeping Stone"". The problem the OP has is with the wall.