Source of Water Leak

Does it leak when the radiators are turned off?

Hi Lyn

Can't really give a good reply to that one since I wouldn't know how to isolate my area and we have large fan blowers rather than radiators. But again it was there this morning and gone by this afternoon. The pipes to the blowers don't appear to show signs of leakage etc but I think this is a larger main pipe that links our building to the others. Just can't be sure without digging.

If you can find a local plumber who has an ultrasonic leak detector, they may be able to find the leak.

Ultrasonic Leak Detectors - Nonelectrical Properties Testing - Grainger

Why not start a class in building maintenance and get some local contractors to volunteer some help? It is a school is it not? I'm sure there are a few strong back weak mind types that would rather be doing that then listening to some boring teacher go on and on....Present company excluded of course.....

Hi Solareagle

You must be up in the clouds here. I need help with this one. My cupboards are rotting and no-one seems to appreciate that if it is a leak it could close the school when the pipe does finally blow. Just need to prove it.

So call a plumber....Issue a work order....Petition the headmaster.....Otherwise, just live with it, time resolves all issues....

This isn't exactly an answer to your problem but I think it is a helpful suggestion. For at least one "test night" leave the lights on and leave a video recorder running (somehow hidden or safe from theft). In the morning you should have a record of the spot(s) where the water entered the room. Not the full answer that you are looking for but useful information.

If necessary, use extra lights positioned as required to get a good shine from the surface of the water.

Also, if necessary, spread tissue paper or powdered chalk on the floor to create a witness of where the water was. This may be limited in usefulness since your interest is where it came from, not where it got to. (Hopefully the janitor is not a big guy with a short temper)

I don't know if the classrooms have internet but a IR sensitive web cam with IR LED illumination could be used and you could watch from home and/or record it. With IR you don't have to arrange to have the lights left on. Many models are available for less than US$100. Your local security or DIY-Spy shop might be willing to let you borrow a demo unit in exchange for letting people (local newspaper, local TV station) know that they are helping at the school.

Thanks Bruce good sensible suggestions. I even thought of glueing a barrier to the floor in a square using polyeurethane glue and wooden battens to see if it filled up or moved into that area from elsewhere to locate it. Easily removed afterwards. I like the webcam idea maybe with time lapse snapshot software worth considering.

You haven't said whether the boiler is steam or hot water. Whether all the lines are run under the slab.

I have found that if there is a leak from either. That area of the floor gets hotter if there is a pretty good leak.

If the systems leaking that much how do they justify the losses. Excessive water bill and high heating cost.

Maybe a strategically placed bucket would solve the problem.....at least temporarily...

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or maybe not....

Wipe some of the leak up with a tissue & smell it - I had a leak on a new ceiling once - turns out it was a cat in the ceiling ;-)

Unless it's Little Johnnys' revenge.

Not a solution, but putting cupboards up off the floor 1/4 to 1/2 inch (6 - 12 mm) will keep the bottoms dry & not rotting. Ceramic (tile or broken tile) plastic, metal etc - non porous should do the trick -

Good luck.

Yes Stuart did that today. Got a sheet of recycled plastic and put it under the cupboard. Great minds think alike.

If you expect leaking pipes, try this:

Cheap and Easy,

1)Get yourself a stethoscope.

2)Turn off all devices that make noise (vibration).

3)Check the aria where you suspect the leak with the stethoscope.

If you have leaking pipework you will hear the leaking,dripping sound very clear with the stethoscope, best to do at nighttime with as less as possible sound pollution.

Good Luck!

GA

If you can't get hold of a stethoscope: use a large screwdriver; put the "large end" in your ear and push the pointed end into the floor; move around until the leaky sound is loudest.

Take care not to use the screwdriver backwards.

Imagine this... Perhaps there is an a/c unit somewhere...not even near. During the night the lower temps in the area allow condensate to form ice near or on the evaporater coils. Then towards morning the building warms up, air in and around the condenser coils too and the condensate ice melts. and so on...

On a friends sailboat, rain or even a heavy dew would cause the water to seep in and around the deckhouse joint. Then it would run hidden inside the deck structure and beams and ceiling for about 6 feet before dripping on to his bunk. The souution was to dribble a hose for a few minutes and then wait a few hours for the migration to take place. After repeated tests the source location was finally found.

Get hold of an FLIR camera and take pics throughout the day in the corner where the leaks appear and disappear. There maybe piping in the walls no one knows about that may have nothing related to the heating system.

1" steel pipes were used in older buildings - up to the 1950s or so. Has the room got double glazing, or original single glazed? Steel framed (by far the worst offenders) from the 30s-50s?

Heating during the day will allow the water to evaporate, with the addition of a class-full of breath during the day. Once the temperature drops overnight, the water will drop out and collect first on the windows, then run to the lowest place available - that corner.

By the time you arrive in the morning the heating will have dried the windows and re-warmed the room, leaving the puddle in the colder corner.

Find out when the heating comes on and come in early one morning to see if there is water on the window ledges. Or open a window for a while when the room is at its warmest to allow damp air to be replaced. This should alleviate the problem.

Hi,

Do you know at what time the cleaning lady does her job? In the evening or morning I guess. Maybe she puts her bucket in the corner, where you find a pool every day, while she scrubs the floor. As she keeps going back and forth to it, dipping her floor-cloth in and out, water splashes all around the bucket. And it probably takes up to the afternoon to dry off!

I might be miles away from what's really going on in your classroom, but it's worth getting informed before spending money on a plumber!

Good luck!

Sounds like an old joke to me...

Good suggestion and we have thought of that one and eliminated it. Thanks.

It sounds to me that something you turn off at night is building pressure that bleeds off until you turn it on in the morning. How do you know its the boiler? If, as you say, there are no maps of the lines it could also be a hot or cold water line, or it could even come from the roof. Maybe if you stay after school a few hours you will see where its coming from. If your school board is interested in keeping the school from rotting away I think they should assume command and deal with it so you can continue enlightening the young ones. Class dismissed! (I always wanted to say that)

Lots of great ideas on this one. I'm impressed! But as a former roofing contractor, I have to ask what is also above and near the leak. Many water leaks I have seen originate on the roof but follow interior walls making them hard to find.

Two ideas not yet mentioned involve roof mounted stuff. Chances are there is nothing near this leak but I thought I'd throw it in for consideration. The key to this problem is in the symptom. That clue is the fact that it is always present in the morning and disappears later in the day. This almost has to be some form of condensation that occurs in the cooler temperatures. As it accumulates moisture, it drains and eventually puddles. It could be ice build up on an A/C line or refrigeration unit if there is a compressor unit near by. It could be from condensation from a steam vent on the boiler blowing against a nearby wall above the room nearby. And by nearby, I am referring to anything within about 15 feet, give or take.

I once had a roofing customer that had a leak on a perfectly cloudless day. It was cold outside and I determined that it was air flow from a vent in the overhang that was cooling the wall near the ceiling. Condensation would only show up when it was cold enough to precipitate moisture from the air inside the house. Covering the vent in the winter was enough to fix the problem.

I'm willing to bet that the pipes are just fine. Look for things that could explain why this only shows up at night during cooler temperatures. Also consider the HVAC usage or dis-usage, at night.

Hi Joe thanks for the input but no air con in the building and the walls are dry but do show damp at low levels probably rising.

A very low tech solution would be baby powder...

Works great for finding those pesky small leaks in a sailboat..

Get a bottle of Baby Powder and spread it around where you suspect the leak may be entering from... You already know where it's going to end up right?

You can make a ring around that area and see what direction it comes into the area from and follow that back....

Bread crumbs in reverse.....

An IR Camera is generally only helpful when there is enough Delta T (Temperature Diff) in a localized spot for the camera to pick it up...

Be prepared to clean up the mess the next day.....

As the answers here indicate, there are a variety of possible causes for this issue. However, unless your building is on a very high water table, I don't think an underground pipe would cause the problem. The leak would dissipate into the surrounding soil. A leaking pipe cast into the floor could cause the symptoms you report.

If you suspect a pipe, you can find the routing using an underground locator. Most electrical contractors have them. The transmitter clamps around the pipe where it's accessible (at the radiator or boiler) and induces a high frequency onto the pipe. You then use the directional receiver to pinpoint the pipe location along its entire route.

If the leak is on an exterior wall, I suggest checking the outside. Mulch, dirt, leaves, etc. piled against the base of the wall form a dam to keep water against the wall/slab joint. The water eventually creates a path through the joint. The landscaping material will hold the water in for days, even a week or more after a rain.

Another possibility is a leaking fire sprinkler line above the ceiling. The dripping water would follow the joists or beams to the side wall and down just like a roof leak.

Great idea with the locator I will ask if anyone on site has one and this should give the answer thanks. In the meantime I have glued a square in stripwood to the floor. If it fills up the leak is underneath. If it doesn`t I will move it till either it does or I locate the direction of flow. I do believe the building has steel pipes in concrete not a good idea and frowned upon these days. Also there are no pipes visible above ground to feed from one building to the next so they must go under. Its hot water by the way not steam but the water pool is cold to the touch in a morning. I could put a data logger thermister glued to the floor and log the temp every 10 min. That would be fun and may show it up when compared to say a metre away.

Many thanks to everyone some great ideas.

Water accumulating in underground fuel storage tanks is an ongoing problem in the field. A low tech solution is a product sold under the brand name of Kolor Kutz paste. It reacts by changing from a light tan color to a vivid pink when in contact with water. The paste cleans right off with elbow grease. There must be a product over there that is used to detect the presence of water in underground fuel tanks there. Good luck.

What you need is the new patented KrisDel leak detector, guaranteed(to be expensive).....The KrisDel divining apparatus is capable of finding anything, when properly used...

Expert leak(and other stuff) locater Hooch the hound dog, we call 'im, can find anything, it's said....

Also available deluxe 2 piece models for just a bit more....

Now that you mention the wall being damp in the morning, especially down low, don't forget to consider drain and sewer lines. Especially if it fails to produce a puddle on the weekend! Bathroom usage is usually higher in the morning than later in the day. Whether it is a leak or an overflow I can't tell you. It could be due to a blockage somewhere in a drain line. Most seals in a drain line are unable to withstand any significant pressure caused by a backup.

Another common "roof leak" was caused by dust accumulation in the drain of a condensation pan beneath an overhead air conditioning system. Refrigerators typically will evaporate the condensation they collect but other systems have to drain it off. So, it could be clean water instead of sewer water.

Do cleaners come in overnight?

If so perhaps either they are leaving the puddle, or something they are doing is causing the puddle.....perhaps a leaky drain from a cleaner's cupboard.

If the puddle is there in the morning, but does not re-occur during the day, something happens overnight to cause it .....

Perhaps a drain from the air-conditioning overflows or leaks when it is shut down .....

Perhaps you could set up a web cam to monitor it and identify the timing, if not the direct cause. That would give you somewhere to start.

Hi again

A quick update. Did a time lapse sequence and converted to video. 1 pic every 15 min low res web cam set up overnight. At around 1.30 in the morning the flood arrives in time with the main boiler house start up. The sequence doesn't confirm yet whether the floor is to blame or water running down the wall so I have set a trap for it on the wall for tonight. Interestingly the water stops flowing later in the day so maybe its a thermal leak which seals itself as the water temp rises. Any thoughts? I used webcam timelapse http://www.tnlsoftsolutions.com/timelapsehelp.php. Nice software although it only set up for low res when initialised. Will have to look into that. See vid below.

http://s567.beta.photobucket.com/user/pj3ns3n/media/Video1.mp4.html

Very good, you have a potential culprit, now to identify the mechanism.....

Is the boiler pressurised? or open to atmospheric pressure?

perhaps an overflow or pressure relief is overflowing to the wrong destination.....

Hi

The boiler is some way from my room 75m and it has a header tank which has been cycling showing a loss. I assume the water is pumped but don`t know the pressure probably quite low. They are water lines not steam.

If it is low, ie atmospheric pressure, there will be a vent/breather from the header tank, also as the boiler heats up and the water(and any air in the boiler) expands, this will flow into the header tank and attempt to vent to atmosphere - perhaps due to an airlock or design perhaps some water will also be vented - if the vent line is broken or damaged some water may vent/leak inside the building instead of outside or into a drain.

Perhaps the header itself has developed a leak.

Sometimes a header tank will have a tray under it to catch leaks and drain them safely outside. These trays or their drains can rust out, or the drains can become blocked.

I sugggest an inspection of the header tank and all associated lines and drains.

There should be ample evidence of any leaks, holes or damage.

I think it highly unlikely (although not impossible) that the header vent will run 75m to a point under a classroom.

Looking at a site plan, where are the boiler and classroom situated with regard to the access route for utilities? Has the teaching block been built later than the boiler house and sited across the pipe run?

In the short video, the water arrives from the right, can the camera be repositioned to look that way, and set to record more frames over a shorter period to catch the route and possibly the method of entry (bubbling suggests rising water, damp patch on wall before water appears suggests water arrives through the wall)?

The header tank could easily be in the ceiling/roof space, from there the vents and drains could run anywhere at the whim of the plumber(s) who installed the system - ie easiest/shortest route accross the top of classrooms where they could easily leak as observed.

Problem finally solved. A 20mm copper elbow, soldered joint leaking at the corner of the room high up boxed in behind a cupboard. Cupboard back was removed, rotted out, and it should be a relatively easy repair. Pity it took a long investigation by me before anyone would set to and sort it out. Probably leaking for a long time with the change in pressure and temperature at boiler start up but reduced during running.

Good job finding it.

Well done, excellent result.

Thanks for letting us know.

Last night I managed to catch some of the water as it went down the wall so it has to be from pipework boxed off above. Now we know the culprit we will remove the covers and have a look. Keep you posted.

Does your destroyer have a timer on the bilge pump?

Does your destroyer have a timer on the bilge pump?

Expect the CR4 consultation fee bill in the mail soon