Leak or condensation

[Glasgow]

We had our bathroom renovated in the summer and a new suite and shower installed. We also installed an extractor fan. The walls are half-tiled and the untiled area of the walls and ceiling are painted in bathroom paint. We were thrilled with it all but...

I have noticed condensation forming on the lavatory cistern (to the extent that it drips on to floor tiles) and in a corner of the room on floor tiles. There have also been a few areas of mould forming on the ceiling. The bathroom is a flat roofed L-shape extension 'bolted on to' a corner of the original house such that the inside of the L which was once an outside wall is now part of an inside corridor to the bathroom.

The more worrying issue is that the wooden door frame (which has been stripped and not yet re-treated) and the lower part of the 'corridor wall' (that used to be the outside wall) just outside the bathroom are both damp roughly where they meet and there is a large patch of mould on the wall. We have been leaving the bathroom door open as much as possible but, if anything, the problem is getting worse.

Any advice as to what further steps to take to resolve the problem or verify that condensation is the issue rather than a leak of some sort would be appreciated. I am not aware of any pipes running too close although there is a radiator on the other side of the wall in the bathrom itself. Many thanks.

 

[Rob]

It shouldn't be forming overnight if its condensation!

 

[tonybhoy]

Probably your cistern is overflowing or you have a leak at the cistern or near to it.

 

[gasmick2]

Hi i have a little saying " heat and ventilation reduces condensation"
most pot cisterns will condensate up to where the cold water level is as the cold water comes in to the warm room,, it sounds like you need some form of permanent ventilation in the room or a automatic fan that gives a lot of air changes per day and night

 

[JohnD]

tell us about the bathroom's extractor fan; at what times it runs, what size it is, how long is the duct to the outside.

 

[Glasgow]

Thanks for the replies I think last 2 (johnD & gasmick2) are probably closer to the mark. It has to be condensation on the cistern (as stops above water mark).

The fan is a Vent-Axia VA100 (XT i think). It is manually operated but with a variable timer that allows it to continue running after pull switch moved to off position. The overrun was originally at about 5 mins and now extended to 30 mins. The shutter closes when the fan stops and the duct goes through a cavity wall - my guess is for about a foot. We put it on religiously when running shower or bath.

It seems to do at least part of its job in that mirror seldom steams up during or after shower. The door is opposite the fan (a distance of about 2m and both in the same 'leg' of the L shape) but this is some distance from toilet cistern. I can live with the cistern problem if necessary - it's the door frame and corridor wall that worry me more. The door is quite a tight fit (especially where the damp is at the bottom).

The radiator was giving us problems before Christmas (no heat) but through delicate manipulation of pressure elsewhere, it seems to have resolved itself. The raditaor is quite close to the floor tiles where condensation is forming and to the toilet.

Hope that helps. Could it be we need a heavier duty extractor?

 

[Glasgow]

Oh and the fan required a 115mm diameter duct to be cut.

 

[tonybhoy]

Oh and the fan required a 115mm diameter duct to be cut.

I'd stake my house on your cistern overflowing during the night or early morning or just simply overflowing period.

Have you checked?

What happens is,particularly during winter,that the constant moving cold water coming from the mains outside going into the cistern condensates on the outside of the cistern becuase of the heat in your bathroom.

Either that or as I said previously it's a leak but believe me it is a plumbing problem.

Trust me I'm a plumber

 

[bengasman]

With a 30 minute overrun I see only 2 opitons.
The fan outlet is nailed shut or you have a leak. Only needs to be a tiny one

 

[Glasgow]

I've just had a look. The cistern is bone dry for the top 4-6 inches then sopping wet all around it's surface below that point. There is water on the toilet rim presumably from the run-off from the cistern. Also the toilet cistern is nowhere near the other problem areas - i.e. other damp floor tiles, door and corridor wall.

I'm happy to give you a few weeks to find another house before we take occupation ofyours!

 

[tonybhoy]

I've just had a look. The cistern is bone dry for the top 4-6 inches then sopping wet all around it's surface below that point. There is water on the toilet rim presumably from the run-off from the cistern. Also the toilet cistern is nowhere near the other problem areas - i.e. other damp floor tiles, door and corridor wall.

I'm happy to give you a few weeks to find another house before we take occupation ofyours!

I'm talking when your not using it for say an hour or more.

Most cisterns these days have internal overflows which means that when they do overflow the water runs into the pan.Only needs to be a trickle but that constant trickle means that cold water-incoming mains water in Glasgow yesterday was 8 degrees probably 6 today-and your hot bathroom means condensation and lots of it.

I thank you.

No it's ok, no need to apologise

 

[JohnD]

I'd also like to leave the fan running 24hrs for a few days as a trial.

my preference is to have the fan come on every time the bathroom light is switched on, then it runs much more of the time.

A bathroom door ought to have a gap underneath it about the depth of a pencil so fresh air can come in to replace the warm moist air sucked out by the fan.

 

[Glasgow]

Tonybhoy - by all means defer your house-hunting for now but there hasn't been any "activity" in the bathroom other than answering nature's call since about 8am this morning. However I do take your point as to why the water may be cold though I'm not sure how this source of moisture could be affecting the door and corridor.

Also my name/handle does not affect my location but my birthplace - I am actually in the south-east of England where we're all enjoying picnics and barbecues at this time of year. Why do ou think I moved? Thanks!

Johnd - both sound like good suggestions to me. I will try the extended fan run and when I get some time I'll trim the bottom of the door.

 

[tonybhoy]

Tonybhoy - by all means defer your house-hunting for now but there hasn't been any "activity" in the bathroom other than answering nature's call since about 8am this morning. However I do take your point as to why the water may be cold though I'm not sure how this source of moisture could be affecting the door and corridor.

Also my name/handle does not affect my location but my birthplace - I am actually in the south-east of England where we're all enjoying picnics and barbecues at this time of year. Why do ou think I moved? Thanks!

Johnd - both sound like good suggestions to me. I will try the extended fan run and when I get some time I'll trim the bottom of the door.

Still say you have a leak of some sort.

Temp is all relative.

Mains temp in Glasgow at 6 degree with outside temp of about 8 and inside temp of 21 degrees means lots of condensation .

Southeast will be hotter but still cold enough to generate condensation.

Door and corridor will be cold to the touch ,think of mirrors or tiles

Water will condensate on cold surfaces.

You clearly doubt my expertise.I am crushed

Have you had a plumber in? You should if you haven't cause it won't solve itself.

 

[Glasgow]

I keep popping in from the garden to check for new posts. Another balmy January evening in Sassenachland. These damned flies though....

Your input is appreciated and your expertise is clearly streets ahead of my own. Please dry your tears.

So are you effectively saying I may have 2 problems:

1. An overflowing cistern triggering cold water triggering condensation.
2. A leak causing the damp around the door and radiator.

We did, in fact, have a plumber in recently - to try and resolve heating problems. I'm wondering whether he may have done something that could have triggered a leak.

I'm beginning to think demolition is the only answer - in which case I'll need that house of yours!