ECN Forum

pvc pipe under driveway

Posted By: tdezo

pvc pipe under driveway - 10/16/05 04:21 PM

hello! I'm wiring a curbside sign and I need to cross a driveway , 15ft wide.I heard about a waterhose trick where you can push a pvc pipe undreground with a gardenhose attached to it but I dont know how to do it "properly" ? Or what water pressure needed? Thanks for any help . Dan
Posted By: renosteinke

Re: pvc pipe under driveway - 10/16/05 05:17 PM

The first, and most important, thing is to bury the pipe deep enough. For a driveway, that means at least two feet deep.
This, in turn, means you will need a hole on either side of the drive at least three foot deep, two foot wide, and four feet long (extending away from the edge of the drive. At the end away from the drive you should dig an additional bucket-sized "sump" for the water to drain into.

For the actual bore, I use 24" lengths of black pipe (3/4"), joined with electrical couplings (sure, the leak some, but are easy on/easy off). At the end of the first pipe is a simple brass nozzle, the type that looks like an old fashioned fire hose nozzle, and makes a sharp stream of water. The last section of pipe has a fitting that fits on the garden hose. Last- but certainly not least- I screw a ball valve on the end of the hose.

Ordinary water hose pressure is enough.

The procedure is simple....bore, stop, add another length of pipe, repeat as needed.

You will get wet and dirty. I usually work from one side untill too much water accumulates- then I move to the other side, and so on. This is also a good time to shovel out the mud that has flowed from your bore.

I say dig deep for two reasons. The first is that the drive actually shifts every time it is used, and this will eventually damage your pipe.
The other is that you will undermine the ground that supports the drive....which will lead to the drive cracking there.
So please do yourself a favor and resist the temptation to run the pipe just under the drive. The holes on either side of the drive- well, the bigger they are, the easier your job will be. If there was a hole specifically designed to be dug with a Bobcat, this would be it!

It will also probably be easier to run the pipe if it is cut into shorter pieces, and assembled as you push it in. Forget tape- glue a pipe plug on the leading end, and cut it off after you're through. Use as large diameter pipe as you can- even if this part is larger than the main pipe run- for your ease of pulling (as well as filling the bore you made).

Where your pipe exits the drive, use a sweep (elbow) to come up into an "in the ground" type of box. These boxes are usually round, grey, plastic, and about the size of a 5 gallon bucket. Your other pipe can enter the box from the side.
Posted By: dmattox

Re: pvc pipe under driveway - 10/16/05 05:21 PM

You can buy a water drill for pretty cheap. You hook it onto a drill moter and use a garden hose. I have done it a few times, its not fun. But it does work.

You need a trench on the side you are feeding the conduit from and a big hole where you are trying to "catch" it. So if its a small area you are probably out of luck.

Also, you don't have a lot of control exactly where you end up. Though my dad likes to tell the story of the time he did it under a schools parking lot that was 150'. He was only a few feet off.

Unless you feel really lucky or the driveway is an expensive material, I would lean towards cutting the pavement. Its hard work, messy and not fun having an electric drill down in a water soaked trench.
Posted By: Dnkldorf

Re: pvc pipe under driveway - 10/16/05 07:28 PM

I've done this trick before:

Take a stick of 3/4" rigid, smash down one end like a point. Using a Hilti and a ground rod driver bit, I was able to "hammer" the rigid under a driveway. I did use duct tape on the threads of the end you are hammer drilling for fear of not getting the next piece screwed on. It worked fine with a little muscle behind it.

Once you get it through, cut off the end you smashed down, I put a rigid compression connector on it.

Posted By: gfretwell

Re: pvc pipe under driveway - 10/17/05 02:00 AM

I shot a 2" PVC 20 feet and hit a foot wide hole in my garage floor.
Use a round plumbing cap. Make a drill head with one big hole in the center ~3/8" and 3 smaller holes ~3/16" near the edge. Glue an elbow and a couple feet of pipe on the far end and use it as a lever to twist the pipe while you push. The hose fitting goes on the end of the lever.
When you find the end, cut off all the plumbing parts and glue on your sweeps.
You will see the target hole filling with water when you get close.
Posted By: electure

Re: pvc pipe under driveway - 10/17/05 02:47 AM

I've always had pretty good luck by doing the same as gfretwell, but by cutting the end of a piece of rigid like an "apple corer", with little triangular pieces taken out.

[This message has been edited by electure (edited 10-16-2005).]
© 2020 ECN Electrical Forums