[scorpionleather]

We have a 6" concrete drain pipe running 10 feet along a flat section and
then 25 feet down a hillside to the lower part of the back yard. Near where
it starts there is an access hole T. About 10 feet away from this access
hole (where the hill starts) the concrete of the floor is caving in a few
inches. This is also close to the corner of two retaining walls. There was
a beehive inside that we had to have professionally sealed up, so apparently
there is a cavity down there. Now, what I am suspecting is that maybe there
is a break in this 6" concrete drain pipe which no one has ever noticed
because it's completely underground, and this break could be causing the
soil erosion (hopefully not, hopefully it's just soil settling). I would
like to check it. I was thinking of getting one of those inspection cameras
with a camera on a long snake, but not sure if it would be long enough and
pricey to use it one time (I wonder if these are available for rent). If I
find a broken section of the concrete pipe, how could I fix it? Some kind
of plastic liner, or pour some kind of epoxy down the pipe through the
access hole?

[scorpionleather]

p.s. somebody might suggest to dig down and check out the pipe, but that
would not be possible due to having to break up concrete ground above a
precarious location near retaining walls and a slope; a huge digging job
could cause more damage than good by displacing soil in a fragile section,
especially if the pipe is not even broken.

[Smitty Two]

In article ,
"scorpionleather" wrote:

We have a 6" concrete drain pipe running 10 feet along a flat section and
then 25 feet down a hillside to the lower part of the back yard. Near where
it starts there is an access hole T. About 10 feet away from this access
hole (where the hill starts) the concrete of the floor is caving in a few
inches. This is also close to the corner of two retaining walls. There was
a beehive inside that we had to have professionally sealed up, so apparently
there is a cavity down there. Now, what I am suspecting is that maybe there
is a break in this 6" concrete drain pipe which no one has ever noticed
because it's completely underground, and this break could be causing the
soil erosion (hopefully not, hopefully it's just soil settling). I would
like to check it. I was thinking of getting one of those inspection cameras
with a camera on a long snake, but not sure if it would be long enough and
pricey to use it one time (I wonder if these are available for rent). If I
find a broken section of the concrete pipe, how could I fix it? Some kind
of plastic liner, or pour some kind of epoxy down the pipe through the
access hole?

Let me be the first to say I'm confused. What "floor" is caving in? Some
portion of the pipe is under the house and some portion is under the
yard? And the beehive was inside? Inside what? What did the cleanup
entail? Are these retaining walls really retaining walls, i.e. do they
have substantial underground footers? Or are they just something piled
on top of the dirt?

I'm thinking, so far, with my limited understanding and pending some
clarification, that you might be able to core the area to probe for
water (mud) without embarking on the "huge digging job" involving
breaking up "concrete ground" (whatever that means) as mentioned in your
postscript reply. But I'm also thinking, you're going to be digging
whether you want to or not. If things are caving in, it's often a bad
sign * whether it's water leaking from the drain pipe or not.

[scorpionleather]

wrote in message Since there are gaps in the
wall where the bees get in, there is an exit for soil and water to wash
out.

Now that you mention it, if there is erosion the soil has to exit from
somewhere, and it was probably where the cracks/gaps were in the retaining
wall. The process of removing the bees forced me to seal these gaps with
expanding foam filler. So now, if there is a break in the concrete drain,
it will get the soil wet underneath but the soil will stay where it is
supposed to and not cross the retaining wall.

[[email protected][_2_]]

scorpionleather wrote:
wrote in message Since there are gaps in the
wall where the bees get in, there is an exit for soil and water to
wash out.

Now that you mention it, if there is erosion the soil has to exit from
somewhere, and it was probably where the cracks/gaps were in the
retaining wall. The process of removing the bees forced me to seal
these gaps with expanding foam filler. So now, if there is a break in
the concrete drain, it will get the soil wet underneath but the soil
will stay where it is supposed to and not cross the retaining wall.

Someone tried foam on our seawall,too, prior to real repairs. Looked
like crap )