Water in loft - stained ceiling

While shaving this morning I was dismayed to find a foot size brownish stain on the newly-painted bathroom ceiling. My worry increased when I located it to a damp patch on the water tank 'platform' above the ceiling plasterboard, just on the edge. How on earth, I wondered, could a thick plastic tank spring a leak? But then I discovered that the cause is probably much less serious, although still surprising.

Covering the top and most of the sides of the tank is a black plastic cladding thingie, with thick fibre glass insulation inside it. (This in turn sits on top of a plastic lid, that fits loosely over the lip of the square tank.) On the underneath of the cladding's top surface there was quite a lot of what appeared to be condensation. And I could just see a trace of water on the outside of the tank itself, below the rim, at the point which would be above the stain.

I know nothing about these things, so would appreciate a few words from anyone who does please. Is that really likely to be the cause? IOW, condensation building up sufficiently to leak out?

Or is it more likely to be this other possibility. At that same point, the overflow pipe leaves the tank, and it was close to that where I saw the water on the tank outer surface. The tank water level was an inch or so below the outlet, but (some 10-20 mins time after using any taps or loos) there was still a drip-drip coming in through the valve.

Reply to
Terry Pinnell
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Condensation can produce surprising amounts of water. The simplest answer is probably to fit a drip tray under the tank, with a drain running outside the building. The long term answer may be to increase the amount of insulation in your loft, so that there is less warm air up there for the water to condense out of.

Colin Bignell

Reply to
nightjar

Thanks for the fast reply, Colin. What surprises me though is that I've been in this house for 11 years, and have never had this problem before. And, although it has been pretty chilly this last couple of days, it's certainly not been a record cold spell.

Fitting a tray would be very difficult, as you see here

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Reply to
Terry Pinnell

Hi Terry. I had a similar problem. The valve was letting in a little water and at night the level went up and leaked through the overflow fitting. Most probably never checked or tested. Baz

Reply to
pjdesign

If the valve is not completely cutting-off the water, then it probably needs a new washer (costs a few pence but watch out if it is an all metal valve as they can be stiff to take apart). Another cause of leaks can be from the vent pipe for the hot water tank or central heating system - these are usually an upturned U shape pipe positioned above their respective tanks and should discharge any overflow caused by a fault in the system into the tank through a hole in the lid - but maybe the water is missing the hole? (the brown coloured stain would suggest it may be from the central heating?)

Dave

Reply to
logized

In my friends house the 25 year plastic old tank leaked and split at the side after sitting on a nail poking through the wooden base. Nail eventually rusted/penetrated the tank allowing water to seep out.

In my latest house during the snaggining I went into the loft (first problem, no boarded access to tank as per regs) and overflowed the water tank on purpose. Water leaked from the tank attachement, not screwed up and from the joint in overflow pipe, not solvent welded !!

Reply to
Ian Middleton

"Terry Pinnell" wrote | While shaving this morning I was dismayed to find a foot size | brownish stain on the newly-painted bathroom ceiling. My worry | increased when I located it to a damp patch on the water tank | 'platform' above the ceiling plasterboard, just on the edge.

I do not want to increase your worries further :-)

But I hope the tank platform is not chipboard that is now slowly dissolving, leading to the tank being insufficiently supported.

Owain

Reply to
Owain

I did have a plastic cold water tank that sprang a slow leak (it cracked near on of the corners - enough to let through a small trickle of drips).

Another possiblity, do you have a hot water cylinder heated from a boiler? Does it have an expansion pipe that returns to the cold tank? If so, it might be worth checking that there is no hot water being delivered into the cold tank by the vent pipe. If so that would indicate a problem with the heating. The result would be lots more condensation.

Reply to
John Rumm

Thanks for all those helpful replies. Cause was almost certainly the simplest, i.e. 16-year old valve not shutting off. I was poised with spanners but chickened out! Plumber cost me £75 altogether. Finished in about 20 mins. Only difficult moment was getting old metal one undone - that's where I would have been worried about breaking it. It was also fairly tricky getting the 'lid' back on, but the two of us eventually managed that. Cladding now looks somewhat untidy, but don't suppose that matters a lot.

I have just noticed that, after running water, there is a lot of noisy 'hissing' as tank refills. Seems to be coming from all pipes en route to the tank and at the valve itself. Definitely wasn't that high pitched noise before. What is likely cause of that please? Sounds sort of like air in the pipes.

Reply to
Terry Pinnell

Sounds like what they call "water hammer", probably just a function of high pressure water through a different type of ball valve. It does not indicate a problem as such and may just be an indication that the tank is refilling faster than before.

If the noise is a problem, then you would have to consider changing the valve for a different design, or perhaps adjusting the flow rate to it with the addition of a stop valve in-line with it.

Reply to
John Rumm

Happily, no - rough but solid-looking soft wood.

Reply to
Terry Pinnell

No hammering or oscillation, just the very noticeable 'whooshing'.

For £75 (15 mins work, with me as unpaid assistant!) I expect it to be done properly, so I've called the plumber back.

Reply to
Terry Pinnell

I reckon you have just suddenly got decent flow after all those years.

If there is air in it, its coming from the incoming mains. Not much you can do.

My CH whooshes too - I use a fairly high pump speed to get it to the far corners, and when going through e.g. ball valves and balancing valves in shorter pipe runs, it whooshes like hell. :-)

Reply to
The Natural Philosopher

That still counts as water hammer... basicaly any noise that is a result of percussive effects of water flowing through the pipes. Tends to be worst with high pressure, combined with small openings through valves, and tight elbows in pipes. You can get the same effect with a tap sometimes, turn it on a little bit and you will get a hissing noise, open it up more and it gets quieter.

Yup, I would go along with that.

Might be worth getting him to fit a Fluidmaster, Torbek, or Siamp valve. These are a different design from the normal ball valve, and tend to be quiter (and fill faster).

Reply to
John Rumm

Thanks both. I'll report back after his visit.

Reply to
Terry Pinnell

On examination, the replaced valve was identical in design to the old (leaking) original. But this morning he replaced that again at my request with a different type, similar to a 'Torbek', noted for being quieter.

After fitting, it sounded only marginally quieter! So I suggested reducing the mains flow. After I'd turned the main tap a quarter turn further in, while still getting a decent direct flow at the kitchen sink, the refill noise diminished drastically. (BTW, I'm surprised the

*plumber* didn't suggest this!)

I suspect the *first* replacement would probably have been satisfactorily quiet if I'd adjusted the tap. But I'd made a point of returning it to exactly the same position as before.

Reply to
Terry Pinnell

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