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Supreme Member


Monday, February 23rd 2004, 6:07pm

Tunneling Success

In the post about Tunnel Under Driveway, I listed how hard and rocky the ground around my house is.

As a part of a test, I tried tunneling under the AC unit (I'm building a raised flower bed starting beside the AC unit, and the slope of the ground made it easy to try) for a distance of about 6 feet.

I started by "drilling" a pilot by pounding a 1/2" piece of rebar under the unit (only needed 4lb sledge). I then pulled that out and pounded a 3/4" "black" pipe topped with a 3/4" to "1/2" reducer topped with a male plug (acted sort of like a tip). Pounding the pipe took a little longer (I'll need to upgrade to a 5lb+ sledge for the driveway I think). But after unscrewing the "cap" and pulling the pipe back out, a 3/4 PCV pipe slide right in.

I'm hoping that this same setup will do for me going under the driveway (except since the driveway is 11' and my pipe is 10', I'll have to get a 2-3' extention to screw on to it) and then follow it with a 1" copper pipe. Note that the fitting over the end of the pipe makes the hole size greater than 3/4", and I can do a little pounding if needed to help get the copper pipe in.

By the way, the pounding royally screwed up the threaded end I was pounding. But the other end was nicely in tact.


Supreme Member

Posts: 372

Location: USA


Wednesday, February 25th 2004, 3:56am

If you intend to do any low voltage lighting I would run wire at this time also. Hope everthing works out.



Supreme Member


Wednesday, February 25th 2004, 6:52am

Had not though of the low voltage lighting, but then this is just a flower bed on the side of the house, and I could always run low voltage wire differently in the future.

My main purpose here was that this 3/4" latteral supplying the new raised flower bed could also lead to flowers in the back yard. I wanted to keep the pipe in the ground, so I had to tunnel under the sides of the flower bed. I had two choises:

1. Turn 90 degrees and tunnel out the front of the raised flower bed and then run the pipe all the way around the rock-bed surrounding the AC unit, or contine strait and tunnel under the raised flower bed AND the rock-bed surrounding the AC unit.

In the end, I decided to try under the AC unit beause...
1. Over-all pipe length and number of elbows is reduced.
2. Trenching to allow the tunnelling was done in backyard (seeded with I don't know what kind of grass) rather than in the sodded bermuda grass in the side yard.
3. Practice to attempt to treach the 11' under my drive way.

However, the point about wiring does remind me that I'm going to have to tunnel under the drive way at least twice: once to get my 1" mainline from one side to the other, and a 2nd time to run wires for valves I expect to install on the far side of the driveway (rather than running latterals back under the driveway).

I could either tunnel out the front and run the pipe all the way around the rock garden surrounding the AC unit, or tunnel under the
My current plans call for a sprinkler system for the grass (using 1" PVC) and a low-pressure sytem for flowers and bushes (using 3/4" PVC). I wanted the pipe supplying the new flower bed to also lead to the back yard for more flowers back there. Once I reached the end of this new raised flower bed, I could either come out the side (b

What I was trying to accomplish with the pipe for the flower bed was to keep the pipe in the dirt and allow it to feed water to the back of the o

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