Q&A / 

Tunnel Under Sidewalks and Driveways

Tunneling Tips for Sidewalks and Driveways

DEAR TIM: I'm installing some low-voltage lighting in the planting beds in front of my home. But a sidewalk is blocking me from running the cable from bed to bed.

I don't want to have to break apart the concrete or saw cut a small groove through it. Is there an easy way to go under the sidewalk with disturbing it? Surely you had to do this once or twice as a builder and can share your secret tools and tricks. Mike S, Kalamazoo, MI

DEAR MIKE: How right you are. I can't think of the number of times I had to extend a drain pipe, cable, irrigation line, gas line, etc. under a driveway, sidewalk or retaining wall without disturbing the finished surface material.

Sometimes, the task was easy; other times it was a nightmare. But you're correct in thinking, I learned some creative solutions to the different challenges.

CLICK HERE to get FREE & FAST BIDS from local handymen that can create a tunnel for you.

Giant Pushed Pipe

My first inspiration for creating invisible pathways came from my fantastic backhoe operator Jimmy Rolfes, Sr. We had to extend a pipe under a six-foot-wide sidewalk and digging a tunnel by hand with a duckbill shovel gave me a headache just thinking about it much less from doing it.

Jimmy showed up at the job site with a large 16-foot-long six-inch diameter steel pipe that had a coned-shaped metal end. He dug a two-foot deep trench perpendicular to the sidewalk and laid the pipe into the trench with the pointed end towards the sidewalk.

He positioned his backhoe and used the hydraulic power of the machine to push the pipe under the sidewalk. The entire operation took about five minutes.

Sleeve It

After he pulled the long pipe back out with a chain, a perfect 6-inch-diameter hole was there under the sidewalk. I immediately installed a 4-inch PVC pipe that extended on either side of the sidewalk about 6 inches.

This sleeve would allow someone in the future to get more cables under the sidewalk. I marked the location of the sleeve on the edge of the sidewalk with a grinder cut.

Smaller Secret

You don't need this type of machine or tool to solve your problem, but the point is, there are creative ways to tunnel under the surface. I learned another fantastic trick from a fellow plumber that might work for you.

We had to extend a new 4-inch diameter sewer line from an existing house to a new detached garage / pool house that was seven feet away. There was a sidewalk between the house and the new room addition that could not be disturbed.

We drilled a six-inch diameter hole through the concrete foundation of the house so a 4-inch PVC pipe could be inserted and tilted at a slight upward angle for drainage purposes.

4-Inch PVC Hypodermic Needle

This plumber used a reciprocating saw to cut a chisel point on a scrap piece of 4-inch PVC pipe. The tip of the pipe looked like a giant hypodermic needle.

This is what the end of the PVC pipe looked liked before we started to tap it in the ground under the sidewalk. It worked GREAT. © 2017 Tim Carter

We inserted the pipe into the hole and tapped a block of wood fitted against the end of the pipe with a sledge hammer until it pierced into the clay soil about 4 inches.

Using a large pipe wrench we rotated the pipe so that the chisel point end cut out a soil plug. We pulled the pipe back into the basement, removed the soil from the inside and repeated the operation.

Within an hour, we had a perfect pathway created that passed from the existing basement under the footer of the new building.

CLICK HERE to get FREE & FAST BIDS from local handymen that can create a tunnel for you.

1 1/2-Inch PVC Works

You can do this exact same thing to create your pathway, but use a smaller one and one-half inch diameter PVC pipe. You'll have to hand dig a trench as my backhoe operator did so that the pipe you are using is parallel with the top surface of the sidewalk.

If your soil is rocky, you'll probably have to use a steel pipe with the chisel cut instead of the more-fragile plastic piping.

PVC Tunnel Tool Video

Watch this video showing how to use a small-diameter PVC pipe to create one of these magic tunnels.

Use Water

Another ingenious method that's somewhat messy, yet effective, is cutting a pathway using a pressure washer. If your wand has a 0 degree tip, you'll be in business.

A 0 degree tip creates a powerful narrow stream of water not much wider than a pipe cleaner. You'll have to dig a similar trench perpendicular to the sidewalk so you can get the wand parallel with the top surface of the sidewalk.

Here's a pressure washer and the wand has a 0-degree tip. You also can see the business end of a duck-billed trenching shovel. © 2017 Tim Carter

Protect Your Eyes

Wear goggles as the high-pressure stream of water will blast out mud, small stones, etc. back towards you as you point the wand directly into the dirt. This method is very effective and depending upon your soil type, you can create a pathway in a matter of minutes.

Stop the spray every few minutes to inspect the size of the pathway you are creating. A 2-inch diameter pathway one foot under the sidewalk should not create any type of structural problem for the sidewalk.

Sleeve It Same Time

If you use a pressure washer, you can actually use a pipe to help control the size of the tunnel. As you start to cut the soil with the water insert a pipe that is a little longer than the sidewalk is wide.

Slide the pressure washing wand into the pipe and start to tap the pipe under the sidewalk as the water cuts the channel. As you remove mud and rocks, tap the end of the pipe with a sledge hammer to drive the pipe. Do this every two inches or so. Protect the end of the pipe with a block of wood to prevent cracking it with the sledge hammer.

If the end of the pipe is always in contact with the soil as the water blasts away, you'll only remove as much soil as the outer diameter of the pipe that is surrounding the wand. Leave the pipe in place once the pathway is created to eliminate settlement problems.

Always Sleeve It

Once your tunnel is created, always install some sort of PVC sleeve. You'll never regret doing this in case you need to run another cable or irrigation line at a future time. Be sure to mark where the sleeve is.

If you want to minimize or eliminate any settlement problems, fill the cavity with sand after the electric cable is installed. Pour sand into the hole and use water from a garden hose to help move it under the sidewalk.

Hand Dig

You can dig pathways by hand with a special duck-billed shovel. These tools have 16-inch long narrow blades that will create a 6 or 7-inch diameter hole.

But the limit of the digging is limited to about half the length of the shovel. It's also very hard to drive the shovel into soil when you're on your knees or twisted like a pretzel in a larger trench.

PVC Needles The Best

The chisel-point pipe method works very well if your soil is primarily clay or a sandy clay. The twisting motion of the pipe cuts a crisp soil plug each time. Use a smaller diameter pipe shoved into the pointed pipe to remove the soil plug.

CLICK HERE to get FREE & FAST BIDS from local handymen that can create a tunnel for you.

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12 Responses to Tunnel Under Sidewalks and Driveways

  1. I have a home in Mich. woodchucks burrowed a tunnel underneath concrete drive right outside garage.Assuming if it goes a the way across to other side,how can I best fill this end so no infiltration of water etc thru winter? I thought of some kind of gophergoo.com or pvc pipe and plug it.Sand is they only other cheap way to fill that I know of. Any suggestions? Thank you very much for responding!

  2. Hello,

    This is some interesting information. I'm wondering if I could do it to make a tunnel for an egress window drainage system. I have no experience in this stuff, but what people tell me is to use a drain tile to carry the water away from the house. I've been trying to think of ways to do that without digging a trench because it would have to be about 5 feet deep and that's too much work. The problem I think I'll run into with this method is that the egress well is only about 3 feet wide, which would only allow me to use 3 feet of pipe for the drilling method. I don't know if that would be a sufficient length to install the tile. Could you offer any suggestions? Do I even need to use drain tile or is there something else I can do.

    Thanks!
    Jon

    • Jon, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!

  3. Okay, my mom is home owners of a neighborhood. We don't have much money or income. And we need to replace electrical wiring under ground due to a mistake by verizon, they cut the line and they are not replacing it, because there is no evidence that they did it. The problem is how can we get under the road without stopping people from getting into and out of the neighborhood without being to expensive. Like cheap. If you can figure this situation out, then please email me at

    [email protected]

    Thanks,
    Zachary HInski

    I wish verizon would just take ownership of making a mistake but, there not, so yeah we need an answer, because we can only have half of the front entrance lit up.

  4. Is it possible to tunnel under a sidewalk made with pavers that are on compacted gravel over a sandy soil (Florida). The pavers are held in place with cement that was placed along the entire edge of the sidewalk. The walk is about 3' wide. I need to get a drain pipe underneath. Thanks for your help.

  5. Had a question about the chisel method above. It appears the plumber drove the pipe under the sidewalk/patio from the basement being the origin. Is that method also acceptable for electrical feeds between two structures?

  6. Hi, I have a plastic gas pipe (poly) which I want to put under my driveway. Do you think the pipe over time will get a lot of stress? Should I use other type of pipes or is it going to work with the astm d2513

  7. I can imagine that having to be detoured because of construction would be a pain. I can see how boring under the road, or sidewalk is better and causes fewer delays. Would need to find a professional that knows how to do it, and do it right.

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