Condensation in bathroom

Cheetah Designs

Cheetah Designs

Cheetah Designs

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Everytime you take a shower, the walls and ceiling have lots of water on them. After the shower, some (not a lot) of water will come dripping in from the extractor fan duct onto the floor.
  • New build (recent). Very generally, it feels well built.
  • Bathroom size is ~4m * ~1.6m * ~2.1m. Considering the slanted ceiling and other bits, you can probably subtract about 20% of the volume of the room.
  • The extractor fan is mounted near/above the shower. I believe its this fan: https://www.airventventilation.co.u...axial-fan-with-timer-and-backdraught-shutter/
  • If I put a tissue to the extractor fan, it sucks the tissue up which I think tells me that there is nothing wrong with the fan, ducting or getting fresh air into the room.
  • The velux window in there has the trickle vent open and there is a small gap under the door for air replenishment.
  • I've tried increasing the underfloor heating temperature to 26*C (sensor is in the floor but the air temp will be lower) and that doesn't seem to have helped either.
  • Fan comes on when you turn the light on and stays on for 5mins after you turn the light off. By the time you turn off the shower, the walls/ceiling already have lots of water on.
  • Tried leaving the window open a little during the shower. With the air temperature outside that obviously drops the room temperature. Doesn't seem to help.
The paint is starting to crack/show signs of wear and we've only been in here a couple of months.
Surely there is something I can do here to prevent the condensation and damage from it?

I will be speaking to the builder, but wanted to be informed on possible remediation steps before I do...Any ideas?
 
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Stupid one maybe but i know my partner loves hot showers, do you have it set to hot hot or just warm ?

That fan isn't great, a separate inline fan push a lot more air.
 
You can get fans that stay on for more than 5mins. I have a CV2GIP that is on at a very low power at all times and, when it detects an increase in humidity, comes on more powerfully. It can also be wired to come on fully when the light is turned on (although I feel that’s unnecessary!).

I also use a squeegee on the tiles & glass in the shower to remove excess water, after showering.
 
Two of our bathroom fans do the same, not helped by my wife wanting it to be turned off at night and her lengthy showers. I’ve just bought a dehumidifier that has solved the problem for the whole house, not just the bathroom.
 
Some options:

Check extractor pipe and vent is all setup optimally, i.e. could this be improved to improve performance of fan? The fact that water is condensing in the pipe suggests poor airflow. Also, if you can make the pipe in the loft less cold, that would decrease the condensation dripping back, but I don't know if this is a typical remedial action.

Fit a more powerful fan.

Are the walls and ceiling smooth? Consider repainting with a water-resistant bathroom paint if that was not used originally.
 
Assuming the fan is ceiling mounted as you mention it drips back? Do you have access to the space above (an attic?). If so, post some photos of the ducting arrangement up there.
 
Our fan is pretty useless but I don't remember it ever dripping. I would certainly look into that.
Otherwise, a dehumidifier might be an option.
 
If the extractor unit is dripping condensate then its poorly specced or more likely installed incorrectly. It should take a route to prevent condensate returning and/or have a condensate trap.

That being said the fact you are getting condensate on the walls so quickly is a concern. As above, water temperature?
 
Showers are hot ones. Don't want to have to run a dehumidifier are a shower, looking for a more permanent solution.

Walls and ceiling are smooth, will look into the paint, what is special about it?...assume it makes the walls non smooth, is that noticeable?

I wasn't able to find any fans that have better performance that would be a drop in replacement...

I had a look and there is some ducting in the loft (the ridgid kind), it must be connected to that and it looks well constructed....but that does make the duct length considerable longer than I thought...probably around 7m.
 
Cheetah Designs said:
Showers are hot ones. Don't want to have to run a dehumidifier are a shower, looking for a more permanent solution.

Walls and ceiling are smooth, will look into the paint, what is special about it?...assume it makes the walls non smooth, is that noticeable?

I wasn't able to find any fans that have better performance that would be a drop in replacement...

I had a look and there is some ducting in the loft (the ridgid kind), it must be connected to that and it looks well constructed....but that does make the duct length considerable longer than I thought...probably around 7m.
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I’d say ideally you would be better with a in-line fan. You’ll need a grill to go in the ceiling and then the in-line fan is put in the middle of the ducting somewhere and are much more powerful than the one you have now.
 
Leave the window wide open for a while after the shower, then close it and leave the fan on.

I'd still hassle the builder to 'fix it' seeing as you're within warranty.
 
Problem I've got is that there is a room in the loft so can't have something running all the time and the lighting wiring is far too far away to hook into it.

I sound like a broken record here, the walls are already wet by the time the shower is over, it doesn't matter how long or far open the window is opened, they are already carrying a lot of condensed water
 
How much of a difference if you drop the temperature slightly? For you to be getting condensation on the bathroom walls outside of the shower means the shower water is very hot and producing a lot of steam.
 
Just get a dehumidifier. It really is the simplest solution. You'll only need it during winter.

I've created a routine for ours now, so it comes on and goes off automatically after half an hour whenever we have a shower.

I had problems with a dripping vent last year. Mine was uninsulated. Over the summer I replaced it with insulated ducting and shortened the route it was exiting. Mixed with running the dehumidifier, haven't had any problems this year.
 
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You need a better extractor fan. Also, check the route of the pipe and where it ends up. 7m is very very long!
 
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Cheetah Designs said:
I sound like a broken record here, the walls are already wet by the time the shower is over, it doesn't matter how long or far open the window is opened, they are already carrying a lot of condensed water
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If you want a temporary cheap way to prevent any moisture damage to the walls, seeing that the walls are smooth, then you can put a squeegee on the end of a pole and squeegee the walls and ceiling after a shower.

Paints marketed as bathroom paints are formulated to resist moisture, so they won't get damaged by the moisture, but moisture will sit on top of them after a shower (probably more so than non-bathroom paint). As it's a new house it should be painted with moisture resistant bathroom paint already, but might be worth a re-coat if already damaged.
 
Cheetah Designs said:
Problem I've got is that there is a room in the loft so can't have something running all the time and the lighting wiring is far too far away to hook into it.
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There should already be 4 core wiring running to the existing fan. A permeant live (with an isolation switch somewhere) and a live from the light circuit.

Our inline fan had a little potentiometer on the circuit board that was adjustable so I could increase the length of time it ran after the light goes off.
 
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