how to find a leakage spot (water passage) in concrete?

[BauTomTom]

Hi

following case: Lift shaft with a kind of sump. That one is full with water and the people don't know hoe it actually gets there, since it flows so slowly in.

Is there a possibility to cover the concrete surface with some stuff and (i suppose as a weak spot the intersection, surface bed and wall) it will indicate the leakage spot?

You know this sprays from the mechanicals to indicate hair cracks in metal elements.

http://www.screwfix.com/p/leak-detection-spray-400ml/41019#

So is something similar for concrete as well? Which would indicate where the concrete gets wet or even water go through?

 

[csd72]

I dont know if it is appropriate for this case but in the gas industry their 'leak detection fluid' is often water with a bit of washing up liquid, then they look for the bubbles. Works for a gas main though maybe not for your case.

Come to think of it, this and the screwfix item are for detection gas leakage and not for water.

Alternatively you can inject an environmentally friendly dye into the surrounding groundwater.

 

[SLTA]

You'd have to back-pressurize the system somehow, right? Otherwise you'd just know that yes, it's flowing in, which you already know. Can you pressurize the shaft with a bit of soap in there and look for the bubbles on the outside?

 

[csd72]

A more primitive way would be to mark horizontal lines with chalk and see where the run marks are.

 

[JedClampett]

I'm not sure of what a "Lift shaft with a kind of sump" actually looks like. But when we have leaks in tanks, we send a commercial diver with a dye wand in. The diver releases the dye and it's sucked into the leak. He/she then marks the location with a waterproof marker for repair.
It's even slicker for the diver to bring in hydrophilic grout, like SikaFix HH and inject that in the leaky spot. It works almost instantly and you can check the repair with the dye wand while you're in there.

 

[paddingtongreen]

Jed, this is like a basement room below the bottom floor. It may have a hydraulic tube through the floor, depending on the type of lift/elevator.

csd72's chalk lines are low tech rather than primitive but probably effective. If there is a hydraulic tube, the seepage could be around that; that is where pressure would be highest. The other thing that comes to mind is condensation but I don't know enough of the environment for this lift.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[MikeHalloran]

If the water is just groundwater, any 'wet basement sealing' product should stop the leak and end the issue. ... without necessarily revealing where the leak was.

If the water is really the hydraulic fluid for the lift, then knowing where it enters the sump is of relatively little value, since you'd presumably rather find and correct the source of the leak in the underground piping.

Assuming the latter, a story:
Our municipality's fresh water system comprises iron or concrete pipes with rubber seals. Twenty years ago, they 'solved' a chronic and widespread leakage problem by adding trace amounts of some nasty chemical that causes rubber seals to swell without limit, so every few years we get to buy a new set of dishwasher valves, toilet tank valves, etc.

Of course, now the underground seals have become so distorted that they don't work anymore, so the entire system is being 'lined' with plastic tubes that are collapsed, inserted with minimal excavation, then inflated, and branches pierced by robots or something.

... all of which brings to mind the idea that maybe the leaking lift pipe could be similarly lined, in situ. The technology is now mature and widely available in the US. I'm not sure of the pressure limits or any other gotchas that might apply here.


Mike Halloran
Pembroke Pines, FL, USA

 

[BauTomTom]

---TO SLTA---
I think as CSD72 already said, this idea with the bubbles can only work by gas but not by water.

---TO CSD72---
You ne, from where do you have all this ideas? I think the chalk lines are the solution. Wwaaoo

http://www so

primitive and such a good idea.

---TO JEDCLAMPETT---
Thanks for the pdf, this looks interesting. (does it seep into the concrete or is it just on the surface?) I attaché a sketch of our situation. In the lift shaft we have a small sump with the pump but the pump was broken and all the lift equipment got damaged by the water.We don’t want to relay on the pump anymore we must see from where the water is actually coming and keep the pump only for emergency if the sprinkler or go on or a pipe breaks in the building.

---TO MIKEHALLOREN---
I assume that it is just groundwater coming up but would really a coating from the inside help? Then the water would go through the whole surface bed, foundations, wall and just stop at the top coating?

 

[BauTomTom]

---TO JEDCLAMPETT---
Waht I actually don't like about the sikafix HH is that it seams like (according to the description) the fluid must be pressed is with pressure pumps. Are there not easier solutions where the fluid actually seep itself into the concrete?

BauTomTom

 

[JedClampett]

For active leaks, applied underwater, the HH is sucked into the joint with the leaking liquid, so no pressure injection is necessary. For dry installation, it probably needs to be applied with some pressure, but not to the extent that epoxy injection requires. You actually don't want to completely fill the crack, because the stuff swells so much, that some of it's going to come out the top. The more void remaining, the more space for the swelling to fill it.

 

[MikeHalloran]

My Dad's house is almost on top of a hill, but it's also on top of an artesian spring. Most of the houses downhill from his have dry basements; some don't. Umpteen coats of various forms and brands of magic masonry paint eventually stopped the seepage through the concrete block walls. Just today I saw a TV ad for "Flex Seal", which you just spray on and the leak stops. Probably overstated, but it might work under the right circumstances.

That didn't stop the water coming in between the slab and the walls. He also had to pay a guy with a jackhammer to remove the periphery of the slab and install French drains and a sump big enough for two sump pumps. ... which still cycle occasionally, even after sixty years (and several sets of pumps).

You could pressurize the sump with one of those blowers that's used to inflate jump houses for kids. Okay, two of them, with regular replacements.

Or you could move the machinery out of the sump and put it on top of the shaft where a decent roof can keep it dry.



Mike Halloran
Pembroke Pines, FL, USA

 

[Ron]

Bubble idea doesn't work for concrete. You can get bubbles from dry concrete.

Use the marking idea....it's about as good as you'll get in concrete, unless you know the source and can inject dye into the source.

 

[BauTomTom]

Thank you to everybody for the good ideas.
I think my best solution will be to dry up the shaft and provide the chalk lines, also around the outlet of the pump, just in case that we have asome backpressure and the water comes through the outlet back again.

The next step will be the HH fluid as JEDCLAMPETT recommended. If it can be really applied without any pressure so then it is easy and fine.

Thanks to you all

BauTomTom