Damp problem around toilet cistern

[nixbarchetta]

We had a new bathroom fitted about 5 years ago, at this time all the walls were skimmed. About 2 years ago the paint has started to bubble on one side of the cistern, presumably caused by damp coming from somewhere. None of the pipework was moved and I can't see anything wrong with the wall outside.

I decided to tackle this area today as I was using some damp seal paint, so scraped the paint off and it seems the plaster has bubbled too. There is also some peeling paint appearing at the other side now too. I have removed the dodgy plaster and paint but not sure of the best way forward?

If I just repair the plaster then paint it with the damp seal I can see it coming back again as the cause wont have been treated but I am unsure what the cause is I'm pretty sure that it's to do with condensation on the back of cistern, the wall behind the cistern is bare plaster. I guess it's soaking in there and spreading outwards through the plaster under the paint and causing the bubbling, or is this a wild theory?

If I repair the plaster then get the cistern removed and paint over the whole area with damp seal might this cure it?

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[Pigeon85]

Did the wall have a mist coat put on before painting?

 

[JohnD]

condensation generally drips off the bottom, and you would see it on the front of the cistern too. More likely a leak. Take some more photos, stand back a bit.

Show us where the supply pipe is, and the window.

 

[nixbarchetta]

Yes, the room was mist coated and the paint is fine everywhere else.

I should have said that there is condensation all over the cistern after a shower, even if you dry it off it comes straight back. It's a very cold room with 3 outside walls, still chilly in the winter with the underfloor heating and the towel rail on. The recent lovely weather has been such a bonus as no condensation There is no evidence of a leak from the visible pipework.

Here's some more pics showing the pipework and the layout.

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[JohnD]

I see from the pipework picture that the pipe is chased into the wall. Where does it go? fingertips may be able to feel it through the plaster (yes, really)


tell us more about the extractor fan.

 

[nixbarchetta]

It feels like the pipe goes off towards the wash basin level with where it enters the wall, I guess it wouldd need to go upwards to be causing the problem and the wall is fine for a good foot before the problem on the wall. The previous bathroom had boxing in around the floor about a foot 10" high that used to hide the pipework.

There is an extractor fan at the top end of the bath but is little used tbh as the bathroom door is always open when the shower is running. I am pretty sure the problem is coming from underneath the paint though and there was no mold on it. We used to get a lot of black mold in the bathroom but since the invention of Bathroom Paint we don't get it anymore.

I do at least know that it is not penetrating damp and we have had some horrendous rain over the last 24 hours and the plaster there is bone dry. I will close the bathroom up completely when I have a shower later and see if any wetness appears. I don't think the cistern is cold enough at the moment to cause an issue, will give it a couple of flushes before hand so the water in it is really cold.

 

[nixbarchetta]

Here's some pics of the damp that has appeared after showering. I closed up all the windows, door and left the fan off in the hope this would happen..... now it has I am still non the wiser lol! View media item 64300 View media item 64301 View media item 64302 View media item 64303 View media item 64304

 

[Pigeon85]

If it is possible then loosen up the screws that are holding the cistern onto the wall and put some spacers between the wall and cistern, I feel it is being caused by damp getting trapped behind which in turn the plaster is absorbing and it is the escaping through this patch on the wall.

 

[nixbarchetta]

Thanks, will see if that's possible, going to get the cistern off the wall and paint all the wall behind it with some damp seal paint so will do that at the same time.

 

[JohnD]

is there any chance that the cistern could be overfull and leaking through the fixing holes? or even a crack?

when spacing it, I find rubber tap washers are good for cisterns as they are slightly absorbent of pressure and unevenness.

 

[nixbarchetta]

I suppose it is possible, but I don't think it can be evident from the inside as we have just had a plumber sort out the dual flush and he never mentioned anything untoward. Worth checking out though, thanks.