it's leaky pipes in the basement season....

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Fulthrotl

~Autocorrect is My Worst Enema.~
i have a customer, amazing as that is in this day and age.

the customer has a basement in a commercial occupancy,
and that basement has three 2 inch and one 4 inch conduits
entering the wall of the basement, about 6' below grade.

for communications.... fiber, 50 pair, all low voltage stuff.
assorted things, making a transition to flex, above a t bar
ceiling.

the conduits leak, not from the outside, but from the inside,
of the pipe, after a strong rain. not continuously,
so it's not groundwater.

so there is either a cracked conduit, or a pulled apart coupling
allowing water in when the rainwater percolates past the conduit
on it's way to groundwater.

now, short of digging it up, my first thought is to cut back the
flexes, remove the flex fitting, use key lock on the threads from
the gal. rigid nipple penetrating the wall, and then pack cotton
around the individual conductors, the same way you'd pack a
seal off, and then fill the coupling with silicone aquarium sealant,
about 2" thick. in addition to that, i will take a three foot piece
of 3/4" vinyl tubing, put a foot up the conduit, seal it the same
way the conductors are sealed, and put a plug in it. this allows
for inspection to see if there is any standing water, and a means
of removing it, if necessary. i'm suspecting that the water entering
the conduit will be less than 2 foot of head pressure, and the
sealant should be ok with that.

whatchoo guys think? anyone got a better idea? i'm open to
suggestions.

plan "b" is to dig it up and fix it. the conduits run underneath a 30'
palm tree, which will have to be removed and replaced. in addition,
the excavating will have to be done by hand, due to the location.
total cost on the thing will on the sunny side of $40k.

thanks in advance...


randy
 
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__dan

Senior Member
Great Stuff

Great Stuff

The "Great Stuff" expanding spray foam sealant that Home Depot sells will seal watertight, sprayed in the entrance nipple.

One other thing to look for if you cannot stop the water from getting in the pipe. There may be an easy way to arrange for the water to drain, maybe sealant and drill a small weep hole in the right location, outside where the conduit enters.
 

jxofaltrds

Inspector Mike®
Location
Mike P. Columbus Ohio
Occupation
ESI, PI, RBO
The "Great Stuff" expanding spray foam sealant that Home Depot sells will seal watertight, sprayed in the entrance nipple.

One other thing to look for if you cannot stop the water from getting in the pipe. There may be an easy way to arrange for the water to drain, maybe sealant and drill a small weep hole in the right location, outside where the conduit enters.

I am not sure if you can use Great Stuff. One thing to concider.

"GREAT STUFF? can be used around and behind electrical boxes and insulated wires, but should never be used inside a box where it may be exposed to bare copper wires."

http://greatstuff.dow.com/faq/
 

Fulthrotl

~Autocorrect is My Worst Enema.~

all done.... went with the polywater product. when dried, it is pretty durable.

actually, rock hard. to ensure i got proper fill, and separation of the conductors,
i wrapped them in the foam blocking material that comes with
the product, shoved that 6" up the pipe, then cut a 1/8" thick piece of
plexiglass in such a way that it held the conductors separate, and allowed
me to see how the fill was working, to prevent voids, and cause i was
curious how it was working.

also put a 1/2" id clear tube thru the plug, with a stopcock on the end,
to drain any standing water in the conduit.

done, billed, check was cut today. rain due this weekend.... test time...

customer also wanted video of conduit, so the rigid micro explorer i got
last year can see up to 30' up the pipe, and has a small enough head,
you can shove it up pipes moderately full.... turns out now there is a
100' attachment for it, but god is it pricey.... so i just took 4 of the
6' extensions and put them togeather, and up the pipe they went....

thanks again for your help on the product selection.
 
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