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.

brendankelly

gsxr1 wrote: »

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.;)

Thanks for the offer of help but I do not have any problems with damp Thank God. From reading the advice here if I had dampness I would have to keep the windows open, Could not have a shower, could not boil the kittle and the bit of sex would be completely out. Thank God I do not have dampness.

paddy147

Lads leave it out will yous,and less of the smart ar5e answers too.:rolleyes:

Everyone is doing their bit to help out here,so dont start whinging on or giving out about the advice given out.

gsxr1

brendankelly wrote: »

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.

Oh. So its not down to a leak then?

Its weeping stone ?

brendankelly

You clearly never heard of weeping stones and I cannot say for definite that it is not down to a leak.

A cold bridge could be any thing for example a dirty wall tie could be a cold bridge. An air pocket in the cavity insulation could be a cold bridge. I have seen the window DPC in a ball at the top corner of windows causing a cold bridge.

If the wall is colder than the room temp there is a problem with the wall.

BostonB

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. ....

A friend had this. Previous tenants in the house 5 yrs no issues. New tenants in the house 2 months and had lots of mould. Tenants leave, new tenants no mould problem.

One place I see mould a bit is in bathrooms/shower rooms with no windows, just extractor fans. The fans can't clear the humidity quick enough.

gsxr1

BostonB wrote: »

A friend had this. Previous tenants in the house 5 yrs no issues. New tenants in the house 2 months and had lots of mould. Tenants leave, new tenants no mould problem.

One place I see mould a bit is in bathrooms/shower rooms with no windows, just extractor fans. The fans can't clear the humidity quick enough.

yeah. I find this also.

One apartment is as dry as a bone with 2 people living in it. The same apartment one year later with 4 people in it is a damp cave.
We are working with homebond trying to find why. We suspect cold weather and constant sauna like conditions, due to clothes drying and over crowding is the cause. Lack of sun on a cold north wall all this can come together to make trouble.

The air is thick to breath. . It really does come down to a moisture balancing act. Even in a place that is built to standard.

Before one tears down or replaces this and that. Understanding how to control the simple causes is paramount. OP it could well be anything as this thread shows . I think you need to get up there and trace the source whether it be leak or simply condensation.

Brenden . You seem to be upset as I sided with Mick. I believe his solutions to be the simplest to cover before considering building defects . It is always advisable by me to not make a mountain out of molehill. Im sorry if this upsets you. I do understand how this happens. Its my job. I have found that that a simple adjustment in climate cures the problem.

BostonB

A leak would cause other problem, like staining before mould I'd expect. Though obviously it would cause mould eventually.

AMG86

Have a look at this link. http://www.proair.ie/index.php?option=com_content&task=view&id=63&Itemid=209. Installation of a HRV system could go some way in solving your problem.

brendankelly

Apologies all aound but if I had not seen it with my own eyes I would not have believed it. Glazed plastering can and will cause damp spots on wall and ceilings. The person that leaves glazed plastering should not be called a plasterer, The site manager that did not cop it was blind and the person that painted it was not a painter..

Skimming should be applied in 2 coats. When the first coat is ""going off"" the second coat is applied. The drying out process causes suction and this in turn makes the second coat porous. Gypsum is not very breathable but glazed skim is the same as glass and condensation will form on it. Glazed plastering is actually a special finish and was asked for in the early 70s for in toilets over the tiles. The idea was that it could be easily washed and would not keep smells. Glazed plastering can only be achieved by applying one coat and troweling it while it is wet.

gsxr1

brendankelly wrote: »

Apologies all aound but if I had not seen it with my own eyes I would not have believed it. Glazed plastering can and will cause damp spots on wall and ceilings. The person that leaves glazed plastering should not be called a plasterer, The site manager that did not cop it was blind and the person that painted it was not a painter..

Skimming should be applied in 2 coats. When the first coat is ""going off"" the second coat is applied. The drying out process causes suction and this in turn makes the second coat porous. Gypsum is not very breathable but glazed skim is the same as glass and condensation will form on it. Glazed plastering is actually a special finish and was asked for in the early 70s for in toilets over the tiles. The idea was that it could be easily washed and would not keep smells. Glazed plastering can only be achieved by applying one coat and troweling it while it is wet.

I also have seen this. I think. It looks like a map on the wall after emulsion paint has been applied. Like a polished finish in parts.

starlight09

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.

Hi Brendan,
I' m interested in what you said. We have a problem with vapour like drops on our ceilings and running down the walls also patches of black mould, for this I use mould and mildew which works great but only for a time. We live in a bungalow, we had the external walls pumped 2yrs ago, made no difference. over the years I have tried all kinds of things, special paint, (waste of my money) opening windows, closing windows, keeping the house warm. We were told to make sure attic insulation was going out properly at the edges which we took care of. We are totally at a loss. Its easy for some people to say that its normal in winter but when it affects wardrobes and ones health, we have to do something. Our bathroom is tiled but still water flows so badly down the walls that the window sill and floor are soaked each morning. I also notice that the outside of the cistern is full of condensation and dropping on the floor. Sorry for going on I'm just so tired of having to mop up every day. My husband says to ask would the soap-block have anything to do with it. Hope you can help.

DCCC

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

hi
sound like trap water in cavity. if your house is bricks make sure weep holes are installed above all external opt. This should do it
if this doesn't work have a builder take a look you should be able to get a free Quot
Best of look

johnb25

starlight09 wrote: »

Hi Brendan,
I' m interested in what you said. We have a problem with vapour like drops on our ceilings and running down the walls also patches of black mould, for this I use mould and mildew which works great but only for a time. We live in a bungalow, we had the external walls pumped 2yrs ago, made no difference. over the years I have tried all kinds of things, special paint, (waste of my money) opening windows, closing windows, keeping the house warm. We were told to make sure attic insulation was going out properly at the edges which we took care of. We are totally at a loss. Its easy for some people to say that its normal in winter but when it affects wardrobes and ones health, we have to do something. Our bathroom is tiled but still water flows so badly down the walls that the window sill and floor are soaked each morning. I also notice that the outside of the cistern is full of condensation and dropping on the floor. Sorry for going on I'm just so tired of having to mop up every day. My husband says to ask would the soap-block have anything to do with it. Hope you can help.

We have similar problems in our en-suite, worse in winter. The main cause is the steam from the shower, which condenses on the walls, especially the external wall. Once condensed it is almost impossible to clear. It is worst near the top of the walls where the cavity is closed, and around the window. In cold, frosty weather leaving windows open is almost useless, as there is almost no breeze or air circulation, and it cools the room. The en-suite has a 4" wall extractor which cannot cope with the steam from two showers in the morning.

I am going to put in a ceiling extractor directly over the shower to try and get the steam extracted before it has a chance to circulate and condense.
The standard 4" shower ceiling fan is something like this http://www.tlc-direct.co.uk/Products/MRSL100TC.html which has a capacity of about 85m³/hr.
What I am looking at is something like this, http://www.tlc-direct.co.uk/Products/SLTD250T.html which has a a capacity of 250m3/hr
Does anyone see any problem with using a fan of this capacity? Is there any reason why I could not do this?
The existing wall fan runs of the light switch, and has an isolator switch. I presume I can tap into this and operate it from the light also? (Will get spark to do it!)

starlight09

Johnb25,
I agree completely with you about opening windows in frosty weather, its a total waste. If you go ahead with 1 of those fans would you please post here how it works for you. It could be an answer to one of my problems. Best of luck with it.

brendankelly

I have a theory on this. Condensation will form on the glazed plastering because it is like glass. What I would like to do is plaster one wall with lime putty and see how much less condensation will form on that wall compared to the other walls. I do not expect that one skim coat of putty will be enough. Naturally I could not charge for experimenting on someone's house so if there is someone out there that is adventurous within range of me get in contact.

johnb25

brendankelly wrote: »

I have a theory on this. Condensation will form on the glazed plastering because it is like glass. What I would like to do is plaster one wall with lime putty and see how much less condensation will form on that wall compared to the other walls. I do not expect that one skim coat of putty will be enough. Naturally I could not charge for experimenting on someone's house so if there is someone out there that is adventurous within range of me get in contact.

Can it be painted over? Will a coat of bathroom emulsion over the lime putty not put a sheen on it again, and back to square one? Surely it is more to do with temperature.

starlight09

On the subject of dampness and black mould, I was told today to paint my room walls with Zinsser B-I-N Primer. It dries into a flat white ready for painting. Has anyone heard of this? Does it work or am I wasting my money again? What about any health hazards? Feedback welcome.

BostonB

johnb25 wrote: »

We have similar problems in our en-suite, worse in winter. The main cause is the steam from the shower, which condenses on the walls, especially the external wall. Once condensed it is almost impossible to clear. It is worst near the top of the walls where the cavity is closed, and around the window. In cold, frosty weather leaving windows open is almost useless, as there is almost no breeze or air circulation, and it cools the room. The en-suite has a 4" wall extractor which cannot cope with the steam from two showers in the morning.

I am going to put in a ceiling extractor directly over the shower to try and get the steam extracted before it has a chance to circulate and condense.
The standard 4" shower ceiling fan is something like this http://www.tlc-direct.co.uk/Products/MRSL100TC.html which has a capacity of about 85m³/hr.
What I am looking at is something like this, http://www.tlc-direct.co.uk/Products/SLTD250T.html which has a a capacity of 250m3/hr
Does anyone see any problem with using a fan of this capacity? Is there any reason why I could not do this?
The existing wall fan runs of the light switch, and has an isolator switch. I presume I can tap into this and operate it from the light also? (Will get spark to do it!)

I've tried unsuccessfully to get a larger fan, my local electrical supplier being utterly useless I gave up chasing them for it.

We have the same problem en suite.

I was wondering, is there a better way to contain the steam. Having a seal ceiling to floor door on the shower and some sort of passive plastic hood over the shower to funnel the steam into some sort of trap, that drains back to the shower tray. An alternative I suppose is some form of wet room, though I don't know if the ceiling is water proofed in that scenario.

Fans I think just delay the problem rather than cure it.

starlight09

brendankelly wrote: »

You clearly never heard of weeping stones and I cannot say for definite that it is not down to a leak.

A cold bridge could be any thing for example a dirty wall tie could be a cold bridge. An air pocket in the cavity insulation could be a cold bridge. I have seen the window DPC in a ball at the top corner of windows causing a cold bridge.

If the wall is colder than the room temp there is a problem with the wall.

As I have mentioned here, we suffer from black mould patches in our room walls, we thought it might be from dirty wall ties as you mentioned so we had the walls pumped with insulation 2yrs ago but it did no good unfortunately. In cold weather the top of the walls (from ceiling) have droplets of water running down. Any ideas Brendan.

The black patches will not come off with just water so I don't think its condensation. These patches are in the area running along over the windows but I did see in one of the rooms where I removed the carpet that the corner floor and skirting board was wet to the touch with a fowl smell.

johnb25

BostonB wrote: »

I've tried unsuccessfully to get a larger fan, my local electrical supplier being utterly useless I gave up chasing them for it.

We have the same problem en suite.

I was wondering, is there a better way to contain the steam. Having a seal ceiling to floor door on the shower and some sort of passive plastic hood over the shower to funnel the steam into some sort of trap, that drains back to the shower tray. An alternative I suppose is some form of wet room, though I don't know if the ceiling is water proofed in that scenario.

Fans I think just delay the problem rather than cure it.

I am hoping that the second fan I linked to above will extract the steam almost as quickly as it rises, and therefore nip the problem in the bud.
Another thought that crossed my mind was to fit a glass panel above the shower screen that would stop steam travelling along the ceiling. I would leave a gap between between it and the shower screen to allow an inflow of air for the fan.

tlc, linked to above, deliver to ROI. I have never dealt with them, but they look like a large enough outfit.