Persistent damp in bathroom with no windows. Solution?

Lit_Up

Shower room/WC has no windows. Walls are partition and not exterior so extraction cannot go direct through a wall. Instead fan extracts through an adjoining room in boxing and out the wall the long way around. Fan already has over-run function.

Would a dehumidifier help to solve this damp issue? For some reason, all the tradesmen who have looked at this bathroom have never mentioned getting a dehumidifier.

Room dimensions are 7ft9in x 4ft10in

Chunks

Location of room (accessible) loft space above?

phill99

It's because the fan you have us as much use as a chocolate teapot. Itsdesigned for extraction straight through a wall, not through metres of ducting. Ifyiu were to cut into your ducting, i guarantee there will be water in them as the steam is just condensing in the dcting before it grts to the outside. You need an inline fan, much higher capacity, much higher flow rate. An inline fan effectively has a pushing and pulling function, rather than just the pulling function tthat you currently have.

Do the extraction properly and you wont need a dehumidifier.

Johnandabby

And don't use the flexible ductwork stuff, it creates so much air resistance that the basic domestic fans can't move any air anyway, particularly with all those bends. Rigid ductwork with an inline fan, sized correctly to deal with the length of ductwork.


Flexible ductwork into a plastic soil pipe?? Worst installation I've seen for a while...

System

also, get a fan with a humidistat on it to make sure it runs long enough - but as the others have said, getting a decent fan and having it well installed would be a good start...

cyclonebri1

phill99 wrote: »

It's because the fan you have us as much use as a chocolate teapot. Itsdesigned for extraction straight through a wall, not through metres of ducting. Ifyiu were to cut into your ducting, i guarantee there will be water in them as the steam is just condensing in the dcting before it grts to the outside. You need an inline fan, much higher capacity, much higher flow rate. An inline fan effectively has a pushing and pulling function, rather than just the pulling function tthat you currently have.

Do the extraction properly and you wont need a dehumidifier.

:T:T:T

Bang on, but it's going to be disruptive, that's a very small room so the solution will be easy.

However you need a minimum 6" dia inline fan. They are much more efficient/effective that any crappy 4" unit you will get from the sheds.

Run as much pipework as possible in rigid pipe, if you have to use a section of flexi, absolutely ensure that there is no dip where condensation con collect and sag the pipe even further.
I've seen these were the condensation forms such a dip in the flexi run that it created a trap like in a sink installation:eek:

If there are no windows are the walls all internal?, if so you should not have mega condensation.

27col

My bathroom has no window, but there is never any condensation. It has a 6" fan which comes on with the light and over runs for a very short period afterwards(less than 5 minutes).