Toilet cistern condensation

[Winelight]

Mains filled toilet cistern with vast amounts of condensation running off it.

It's already boxed in. The bathroom has (working) humidstat extractor fan. The bathroom has heating.

So that rules out the three most commonly suggested "fixes" which leaves me with the other things that people have suggested from time to time:

Drip tray. These don't seem to exist, or I can't find them. Tri-wall cistern. These don't seem to exist, or I can't find them. Insulated cistern. These don't seem to exist, or I can't find them.

So that just leaves:

Insulate the interior of the cistern myself. It seems I have a choice of cutting up a yoga mat and gluing it on (I can't see that working, at least not if I do it, anyway), or spraying some kind of insulating foam on the inside.

Does that sound right? Or have I missed another easy solution?

[Rod]

We too have boxed in cisterns. One of those is mains fed. Neither exhibits any condensation. (Not saying that there is never any trace if you looked hard. But there is never any sign of there having been dampness.)

Both are mildly heated (except when actually using the bathroom).

I think that the humidity is still high in your bathroom - regardless of the humidistat. We have a very cheap clock/thermometer/hygrometer. Maybe you could get hold of one and actually check the (relative) humidity levels?

[Bob Minchin]

This suggests to me that the humidity is still too high in the the boxed in section. Maybe you should increase the airflow from the warmed bathroom area into the boxed in area.

Could it be that moisture laden air is getting into the boxed in area from somewhere else/floor below or adjacent room.

Both our bathrooms have boxed in cisterns and don't seem to exhibit this phenomenon.

Bob

[David Hansen]

On Sat, 20 Dec 2008 08:18:58 -0800 (PST) someone who may be Winelight wrote this:-

Don't feed it from the mains.

Others are right, if there is vast amounts of condensation then the humidity around it is probably somewhat high.

[Winelight]

It must be the humidity around it rather than the humidity generally... the bathroom humidistat is adjusted as low as practical without the fan actually running 24x7 (which it does anyway in the summer of course). The humidity from the rest of the house should be low - humidstat fans in the kitchen and utility room, but the kitchen one rarely comes on because of course there's another extractor fan over the cooker.

But there's no ventilation at all for the boxing around the cistern. The cistern is against an outside wall so the boxing will have the effect of lowering the temperature in the boxed area, if that makes any difference.

[Ian Vandahl]

I put a flexible piece of pipe with a coil in it inside and then hooked it up to the central heating. It warms the water, so no condensation. And it flushes with fairly hot water!

[Winelight]

Thanks for the suggestion, that would be good but we don't have hot water heating!

[dennis]

Aquarium heater?

[Invisible Man]

In a former house I just put a receptacle underneath to catch the drips. The water supply and stop valve were in the cloakroom. I put plastic pipe covers on the pipes but when very cold mains water enters a warm house it is difficult to avoid some condensation.

[John]

Never understood why small bathrooms have a cistern in them - for an upstairs bathroom a cistern in the loft would free up space in the bathroom and give a better flush. Bring back the chain!

[Winelight]

Actually, thinking about it, presumably people don't usually recommend spraying the outside of the cistern with insulating foam because it will look naff?

But, this cistern is boxed in. So I might just do that.