I don't think anyone here is agreeing with that theory.
Have I created a condensation problem?
- Thread starter kenam
- Start date
I don't think anyone here is agreeing with that theory.
Sponsored Links
No.. that was my thoughts initially - only because the bathroom is always cold..
Sorry - I missed your earlier post as well:
Need to test - but I need to change the door anyway as the floor was tiled and the door sticks on one side - so will be a contributing factor I guess.
Straight out
Need to test - but I need to change the door anyway as the floor was tiled and the door sticks on one side - so will be a contributing factor I guess.
Consider masonry for the ceiling, the anti fungicide will keep the mould at bay.
Don't forget to mist coat the bare plaster first.
Don't forget to mist coat the bare plaster first.
Sponsored Links
I would hope that almost any fan should be able to extract OK in that situation, unless it's actually broken.
Is there sufficient gap under the door to let air in?
More heating, or better insulation, so that the walls are warmer before you shower will reduce the visible condensation.
But in some sense it's better that the moisture condenses here where you can see it, rather than escaping into the rest of the house and condesning on the wallpaper behind the bed in your spare room and causing lots of black mold. (See other threads!)
Is there sufficient gap under the door to let air in?
More heating, or better insulation, so that the walls are warmer before you shower will reduce the visible condensation.
But in some sense it's better that the moisture condenses here where you can see it, rather than escaping into the rest of the house and condesning on the wallpaper behind the bed in your spare room and causing lots of black mold. (See other threads!)
There prob isnt a sufficient gap - floor was old carpet and now tiled - raised by about 8mm (and causing the door to get caught on the floor).
I guess my next experiment is that I need to shower with the door ajar. If that clears it quicker, then I will replace the door sooner rather than later (or plane a bit off the bottom!)
how old is the fan? can you post a pic? Mine is only about 80 cu.m/hr, which is about the smallest, but it runs all the time the light is on, and keeps the bathroom free of condensation (except the window, which steams up)
there used to be a mist of condensation on the external walls in winter during a bath or shower before I had CWI; they are warmer now.
No need to have the door ajar, a gap you can push a pencil through is enough. It is actually more efficient if the gap is under the door, because the fresh dry air will enter at floor level, and the warm moist air will rise towards the ceiling and extractor (water vapour is lighter than air, hence clouds).
It works better with the door and window shut.
How do you heat the bathroom, and why is it cold? is there a non-return flap on the vent, to keep the wind out?
there used to be a mist of condensation on the external walls in winter during a bath or shower before I had CWI; they are warmer now.
No need to have the door ajar, a gap you can push a pencil through is enough. It is actually more efficient if the gap is under the door, because the fresh dry air will enter at floor level, and the warm moist air will rise towards the ceiling and extractor (water vapour is lighter than air, hence clouds).
It works better with the door and window shut.
How do you heat the bathroom, and why is it cold? is there a non-return flap on the vent, to keep the wind out?
Fan in completely wrong position, need to be above shower encloser or if not possible, immediately outside it.
It seems that everyone has so widely differing opinion on this subject of bathroom condensation, and experiences, I might add mine if it may point to soemthing. I must be very lucky then for I don't have any condensation problem on my tiles or ceiling, and never ever had any mold or anything like it, except the grout and bath silicone seal often tends to get a bit discoloring and applying thick bleach soon restores it to clean white colour.
I am also lazy when it comes to finishing jobs in my own house, my bath ceiling has never been painted or even sealed ever since a plasterer skimmed it perhaps 10 years or more ago, yes I let it go unpainted, and during shower or bath, it gets a bit wet and so the colour changes from light brown to darker wet brown, as the plaster absorbs moisture but soon dries afterwards, within about 15minutes to half an hour, depends how long you take shower for, or run your bath for. The longer you spend under a shower the more darker it gets.
1. My bathroom does not have an extractor fan. It never had one and I didn't bother fitting one. We use our vent opening to allow moist air to expel after a bath or a shower.
2. I also leave the bathroom door wide open after a shower or a bath, but only for as long as it takes me to go into my room to get dressed up, clothes and shoes on, and do my hair etc, and so roughly 10minutes later the door is shut tight, leaving the window vent still open. we close the vent an hour or so later.
3. There is no heated towel rail or any radiators in my bathroom.
4. Now this is the bit why I don't get any condensation, I use a 1.5kw electric convector heater set to give constant 18c even when not using the bathroom, and when we are using the shower or bath we turn it up to 25c, and then leave it running for about 30 minutes after taking the bath or shower before turning it back to 18c.
5. For safety it is wired up on its own local RCD protected spur and is mounted well away from the tub or sink and is in a safe zone.
6. i must say I get very small amount of condensation on my bathroom window around the edges, in cold weather like now, this is because we keep the vent closed for most of the times and don't want cold air blowing in. But all my ceiling and tiles are clean and mold has never had a chance to take hold.
7. One day i will pick up the courage and paint my bath ceiling.
8. I get more condensation on my bedroom window despite having a radiator in that room, this is the general condensation as a result of aspiration, from cooking
and drying clothes indoors.
9. Finally don't take me wrong, every time one uses hot water shower or bath, condensation will be there, but if you have a strong heater, it heats up rapidly all cold surfaces so the condensation just cannot settle as much, even my shaving mirror remains clear after a shower, due to my convector heating, and vapors are then expelled through the window vent. About half an hour is all you need.
One can use a hot air blower heater fitted just outside the bathroom fitted at a high level and blowing warm air into the bathroom through a duct with a vent, to expel moisture through an open window or vent.
In my other house, where there is no convector heater, or forced warm air heaters, bathrooms tend to get mold. Despite CH radiators being left on. As well as the bathroom fan that shut off 10min after the light switch is turned off, there is no window in this bathroom to expel any condensation, so a fan is a must here.
So unless people living in this house (tenants) if they don't follow instructions given to them, i.e. after bathing or showering, they must keep the bathroom door open for at least 15min to as long as they want. Problem gone, they did start getting mold.
I am also lazy when it comes to finishing jobs in my own house, my bath ceiling has never been painted or even sealed ever since a plasterer skimmed it perhaps 10 years or more ago, yes I let it go unpainted, and during shower or bath, it gets a bit wet and so the colour changes from light brown to darker wet brown, as the plaster absorbs moisture but soon dries afterwards, within about 15minutes to half an hour, depends how long you take shower for, or run your bath for. The longer you spend under a shower the more darker it gets.
1. My bathroom does not have an extractor fan. It never had one and I didn't bother fitting one. We use our vent opening to allow moist air to expel after a bath or a shower.
2. I also leave the bathroom door wide open after a shower or a bath, but only for as long as it takes me to go into my room to get dressed up, clothes and shoes on, and do my hair etc, and so roughly 10minutes later the door is shut tight, leaving the window vent still open. we close the vent an hour or so later.
3. There is no heated towel rail or any radiators in my bathroom.
4. Now this is the bit why I don't get any condensation, I use a 1.5kw electric convector heater set to give constant 18c even when not using the bathroom, and when we are using the shower or bath we turn it up to 25c, and then leave it running for about 30 minutes after taking the bath or shower before turning it back to 18c.
5. For safety it is wired up on its own local RCD protected spur and is mounted well away from the tub or sink and is in a safe zone.
6. i must say I get very small amount of condensation on my bathroom window around the edges, in cold weather like now, this is because we keep the vent closed for most of the times and don't want cold air blowing in. But all my ceiling and tiles are clean and mold has never had a chance to take hold.
7. One day i will pick up the courage and paint my bath ceiling.
8. I get more condensation on my bedroom window despite having a radiator in that room, this is the general condensation as a result of aspiration, from cooking
and drying clothes indoors.
9. Finally don't take me wrong, every time one uses hot water shower or bath, condensation will be there, but if you have a strong heater, it heats up rapidly all cold surfaces so the condensation just cannot settle as much, even my shaving mirror remains clear after a shower, due to my convector heating, and vapors are then expelled through the window vent. About half an hour is all you need.
One can use a hot air blower heater fitted just outside the bathroom fitted at a high level and blowing warm air into the bathroom through a duct with a vent, to expel moisture through an open window or vent.
In my other house, where there is no convector heater, or forced warm air heaters, bathrooms tend to get mold. Despite CH radiators being left on. As well as the bathroom fan that shut off 10min after the light switch is turned off, there is no window in this bathroom to expel any condensation, so a fan is a must here.
So unless people living in this house (tenants) if they don't follow instructions given to them, i.e. after bathing or showering, they must keep the bathroom door open for at least 15min to as long as they want. Problem gone, they did start getting mold.
Last edited:
I can't entirely agree with that. "Completely the wrong position" would be right next to the door. With this layout, at least some of the dry air from the door does pass the shower before reaching the fan - though that may depend on how the shower door / curtain is aranged.
But yes a ceiling fan directly above the shower would be better.
ye -seems I have naively thought a towel rail and extractor (in any position) would be enough. The bathroom is tiny (1.7 x 1.9) meters I guess thats why I thought it would be fine (or I never thought much at all!).
Maybe I will get lucky with a better air gap under the door, if not I will try swapping out the towel rail for a larger one..
if that fails.. then need more drastic action (or wait for the summer and forget about it for another year
)
Cheers again all - plenty to consider!
Maybe I will get lucky with a better air gap under the door, if not I will try swapping out the towel rail for a larger one..
if that fails.. then need more drastic action (or wait for the summer and forget about it for another year
)Cheers again all - plenty to consider!
The moist air from when you open the bathroom door does not get drawn into the rest of the house then, and magically just stays on the other side of the door threshold?
An unbelievablly long thread for such a simple situation.
Using the bathroom produces excessive amounts of water vapour.
This goes instantly into the air.
The air becomes saturated (100% humidity) within minutes
No amount of heating will alter this fact, ie make it less humid
The air can't hold this much moisture, and the moisture condenses on the coldest surfaces.
The moisture is absorbed into porous materials and surfaces.
Extraction is the only way to reduce humidity (and associated condensation). Heat makes no difference
Fans give a constant means of extraction
Windows (being bigger than fans) can give a quicker means of extraction, but rely on air pressure.
Opening a bathroom door does cause the moist air to move from the bathroom to the rest of the house.
Later on, this could end up condensing in other rooms
Several hours later, moisture is still evaporating from the porous materials and surfaces that absorbed it. That could be going out of a fan or window, or out of the door into the rest of the home.
This is all scientific fact. The degrees to which it occurs can differ in individual properties.
Using the bathroom produces excessive amounts of water vapour.
This goes instantly into the air.
The air becomes saturated (100% humidity) within minutes
No amount of heating will alter this fact, ie make it less humid
The air can't hold this much moisture, and the moisture condenses on the coldest surfaces.
The moisture is absorbed into porous materials and surfaces.
Extraction is the only way to reduce humidity (and associated condensation). Heat makes no difference
Fans give a constant means of extraction
Windows (being bigger than fans) can give a quicker means of extraction, but rely on air pressure.
Opening a bathroom door does cause the moist air to move from the bathroom to the rest of the house.
Later on, this could end up condensing in other rooms
Several hours later, moisture is still evaporating from the porous materials and surfaces that absorbed it. That could be going out of a fan or window, or out of the door into the rest of the home.
This is all scientific fact. The degrees to which it occurs can differ in individual properties.
you have a sealed box with a fan running you get low pressure in the box
that reduces the efficiency off the fan
you introduce a small gap to draw in air the pressure is still lower in the bathroom as the fan removes the air quicker than it can enter
its when the gap becomes to big and the fan cannot remove the air quick enough thats when the damp air can reach other parts off the house thats why i suggested a door cracked open with a 6mm gap as an experiment
that reduces the efficiency off the fan
you introduce a small gap to draw in air the pressure is still lower in the bathroom as the fan removes the air quicker than it can enter
its when the gap becomes to big and the fan cannot remove the air quick enough thats when the damp air can reach other parts off the house thats why i suggested a door cracked open with a 6mm gap as an experiment
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
