Installing a Pipe under a Driveway or Sidewalk

The easiest “do-it-yourself” way to get a pipe under pavement is
hydraulic boring.  Take the pipe you want to place under the driveway
and connect a sweeper nozzle (used to hose off driveways) to one end
and a hose to the other.  Glue “hose thread” adapters to the ends of
the pipe to connect the nozzle and hose (you’ll need one male and one
female adapter).  Dig a trench on one side of the driveway and an
exit hole aligned with the trench on the other.  Turn on the water
and shove the pipe under the driveway.  The water blast from the
nozzle will dig a hole as you push the pipe under.  Be prepared to
get very dirty and wet!  After the pipe is under the driveway, remove
the nozzle and hose, and cut off the adapters.  You now have a pipe
under the driveway.  The hole around the pipe will be somewhat larger
than the pipe, which can cause a problem with asphalt driveways.  If
the soil above the hole collapses, the asphalt will give way under
the weight of a car.  If you want to chance it with an asphalt
driveway, make sure the pipe is 18″ deep under the asphalt, so there
is more soil to support the weight.  You can dry to push concrete
into the hole around the pipe to fill it in and give more support,
but this is difficult to do.

Boring tools are available which work better in rocky soils and under
asphalt.  These tools “drill” a hole using a bit.  You can rent them
at some rental yards, but in most cases you are better off hiring
someone to do it for you.  These guys have boring tools that can
drill over 100′ and even can make minor turns as they bore.  So they
can get a pipe from the front yard to the back under a sidewalk or
patio.  When boring under asphalt, most boring companies will install
a sleeve as part of the boring work to support the surrounding soil
and prevent the asphalt from settling.  You then push your irrigation
pipe through the sleeve.  Look in the yellow pages under “Plumbing”
for companies that do “trenchless” installation or “boring”.  If none
list those services in their ads, try calling a professional plumbing
supply store and ask if they can give you a referral to a company
that does boring.  Often these specialized companies are just one guy
with a boring machine and don’t advertise.  They tend to be pretty
busy because of all the communications cable installation going on
with the Internet expansion.  Most telephone cables are now bored
into place to minimize damage to roads and property.

Sometimes for asphalt driveways you will need to “sawcut” a trench
through the driveway, then repair the driveway after the pipe is
installed.  For companies that saw asphalt look in the yellow pages
under “Concrete Breaking, Cutting & Sawing”.

Hope that helps!