Our water main comes in behind/below the kitchen cupboards, in winter (and cooler times of the year) we get a lot of condensation on the pipe, I’ve lagged the pipe but there is still enough to cause a bit of mildew in the cupboards. I’m pretty sure this is just condensation not a leaky pipe, eg this morning there were several big drips forming on the tap handle.

There are no heating pipes running under there or built in electrical units so no heat to dry it out. Any ideas on how to combat this damp?

<just done some googling, ventilating the cupboards seems to be an idea, presumably just drill some holes in the back of the cupboard…?>

Double lag the pipe. The biggest size of foam wrap goes nicely over 15/18mm lag.

Yes.

I once lived in a bedsit with a very damp cupboard, which I sorted by leaving a 40w light bulb on a brick burning under an old coffee tin, whch I painted black inside and punched some holes though the bottom. The warmth was enough to dry it out permanently.

Improve ventilation

Silica gel sachets or a bowl of rice (replaced regularly)? Or those shoe drying pouches (like a reusable silica gel pouch)?

More lagging?

Set fire to it. I believe cheap lights off ebay are handy for this

if it smells like a leak and looks like a leak – its probably a leak.

make dish and measure how much water there is.

remember your cold incoming is no colder than anyone elses…. so why are you having damp issues and we are not….

I’m struggling to see how condensation on a rising main can lead to damp cupboards (plural). Is the rising main plastic or metal?
I would have thought more heat and ventilation in the kitchen generally would help.

Edit:

if it smells like a leak and looks like a leak – its probably a leak.

Mr Rat is likely to be on the money. It’s prob a leaking tap.

bit more googling and I appear to have veered from cheapo “stick some holes in it” to “buy a dehumidifier”.

a 40w light bulb on a brick burning under an old coffee tin

I was wondering about a light – or maybe some sort of extractor fan built into the end kickboard (fridge is there so would hide it) to improve airflow

There are no heating pipes running under there or built in electrical units so no heat to dry it out.

and

fridge is there so would hide it

does not compute.

fridge = heat.

i assume it is on an external wall as well so perhaps the wall is damp?

Put all your bike parts somewhere else and stop worrying.

if it smells like a leak and looks like a leak – its probably a leak.

I dried it with towel and didn’t seem to be any “seepage”, plus water dripping from tap handle isn’t from a leaky pipe.

so why are you having damp issues and we are not

dunno, maybe more people have hot water pipes nearby to negate it or built in fridges and cookers creating some heat….?

Is the rising main plastic or metal?

metal. It’s also a bugger to get to – I had to climb into the cupboard and twist my arms into some strange positions to get at it, so lagging on it is basic and not fitted very well.

does not compute.

sorry, the kitchen units are all boxed in with little airflow and then next to that a freestanding fridge, no heat source for the fitted units but it would hide the fan. Kitchen itself is generally warm, big cooker, radiator in other corner but under/behind these cupboards it feels chilly and a bit damp. I’m currently thinking condensation plus limited airflow is the problem

leave the door open a bit then and see if it solves your issue – rather than drilling holes in your cupboards for now.

If the pipe’s cold then any ammount of ventilation will just draw moist air in from the kitchen and cause more condensation on the pipe.

If you want a cheap way to rule it out though then silica can be bought cheap as cat litter (check, there are a few types).

Stick a few kg’s in a big baking dish in the oven at it’s highest temperature for an hour or two, if you’ve got accurate scales you can weigh it and see when it stops geting lighter, then put it in the cupbaord. I did it after flooding a kitchen and it dired it out so thoroughly that the plaster behind the cuboards cracked.

I dried it with towel and didn’t seem to be any “seepage”, plus water dripping from tap handle isn’t from a leaky pipe.

Mine was, a drip from the stoptap, turned into a dribble, turned into water pissing out.

plus water dripping from tap handle isn’t from a leaky pipe.

just put a bowl under the stop tap for a day or two and find out how full it gets. it may well be a leaking gland nut:
http://www.ultimatehandyman.co.uk/how-to/taps/fix-leaking-stopcock

or you could call a plumber, who could do one of two things…
a) repair the gland nut there & then or
b) tell you the whole pipe either side of the stop tap needs replacing, replete with sharp intake of breath and the words “it’ll cost ya”

how do I know this? just had the very same problem
First plumber to arrive opted for “b”. second plumber to arrive opted for “a” for £20. probably overcharged but cheaper – and quicker – than option “b”

Not really room to get a bowl under there, pipe comes out of the ground, hugs pretty close to the ground for ~8″ then goes up the wall, there’s no discernible puddle underneath. I’m not ruling out that the stop tap is on the way out and I could get home to a flooded house tonight but this is what I mean by dripping from the handle
[url=https://flic.kr/p/pyAwSA]drippingtap[/url] by D0NK
I’m not sure how a leaky tap can get water up onto the handle.

Don’t know any plumbers so I’d wager I’d end up with option B john drummer 😕

If that’s the orientation of the tap then it’s probably fine. I still don’t see you a little bit of water on the pipe can transfer to the inside of the cupboards.
There again if there has been a constant slow leak from the pipe somewhere this could make the floor/wall damp and cause the mildew.
I’d be suspicious of a metal rising main – possbily leaking under the floor.
Hopefully it’s an environmental issue. Is there an extractor in the kitchen and do you use it?

I’m not sure how a leaky tap can get water up onto the handle.

well it is under pressure…

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Ventilation. I normally take the hole saw to the plinths, placing two or three holes together under very base unit and then using a rectangular vent cover to hide them up again.

If it’s condensation, even this additional air flow will help and just monitor it to see if you need to do more. The passive fan idea is a good one if you don’t feel the plinth vents are enough.

well it is under pressure

aye but if there was a fine spray coming from the tap body I’d see it 🙂 but other wise tap looks fine.

Slackalice, cheers an answer I wanted to hear 😆 tbh haven taken plinths off altogether for now, might aim a fan heater under there this evening to dry the area out a bit*, see how it goes after that. Have managed to get a plate under the pipe, see if there’s any water on it tomorrow.

*just had another look, not even particularly damp, just kinda musty

The passive fan idea is a good one

What on earth is a passive fan? That’s an oxymoron, surely?

What on earth is a passive fan?

Dunno but some crazy yank has patented it

The whole corner is damp thanks to lack of air circulation and a local cool spot produced by the rising main. The moisture trapped in the area is condensing on the cold pipe and tap and forming the drips. That evaporates slowly and contributes to yet more condensation. Increased ventilation should solve it.

I’m not sure how a leaky tap can get water up onto the handle.

The tap handle is cold and the air is wet – thats why theres water on the tap handle – but the wet has to be coming from somewhere, its not being synthesised by the presence of a cold tap handle and theres only so much moisture the air in a closed cupboard can hold.

“buy a dehumidifier”

You’ve already got one – a dehumidifier would be doing exactly what you cold tap handle is doing 🙂

what about putting an outside tap cover on the stopcock too as well as lots more lagging on the pipe? Just try and isolate as much of the cold pipe as you can and get some air flow from the back of the fridge.

Most fridges have some sort of drip tray at the back to catch condensate which would be adding to the moisture back there and the coils will obviously be warming the space too. + all the other humidity you get in kitchens.

do you have an outside venting extractor and do you use it?

Ah right, I see what your saying maccruiskeen, wouldn’t you expect a puddle aswell if it was leaking tho?

No extractor fan/vent no.