Digging Trenches- FAQs
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- How deep should I dig the trenches?
- This depends on how tall your sprinklers are. For most 4 inch pop-ups you will need to dig trenches about 9 inches deep at the sprinklers. To know for sure how deep to dig, assemble a sprinkler on a fitting and measure the height from the bottom of the fitting to the top of the sprinkler.
- What is the best way to dig the trenches, by hand or a with a machine?
- The easiest way to dig trenches is with a machine, but you can put the system in a section at a time by hand if you like exercise and you have a strong back. Even if you use a machine, you will need to dig some of the trench ends and tight places by hand. You will dig most of the backflow hole by hand, and will occasionally trim off corners and remove rocks the trencher couldn't dig out.
- If I rent a machine, should I rent a trencher or a vibratory plow?
- In areas with large rocks your choice is limited to the trencher, but in areas with soft or sandy soil, you may be able to use a vibratory plow which will not leave huge cuts in your yard.
- What if I run into roots or rocks?
- You can go over, around, under, or through them. You'll have to decide what is best in each case. Try to avoid cutting large tree roots.
- How long will I need to rent the trencher?
- Most people need a trencher for a full day if they are doing their entire lot. If your yard is especially large, you may need it for two days. Try to rent it on Friday at the end of the day and return it Monday morning for a one day rental fee.
- Where can I rent a trencher?
- Many tool rental stores rent trenchers. If you find one that does not, ask them if they know of one that does rent trenchers.
- Can I get someone to do the digging for me?
- You can hire day labor to help. You may find some landscaping firms who will do this for you. If you call an irrigator for help, you will get a skeptical person who knows they missed a sale, and they will probably spend time trying to convince you that you made a mistake by not having them do the whole job. It may bother them if you ask questions, since it will support their belief that you are trying to get their professional assistance at day labor prices. We suggest you hire people who dig for help with trenches, and hire an irrigator if you want someone to put your system in for you. If you hire an irrigator to install everything for you, they will probably take issue with your design (no two people design things the same way) and will be reluctant to stand by their work with a warranty. Most irrigators are reluctant to help do-it-yourselfers with their own installations.
- Do I need to tunnel under the driveway?
- Most jobs do not require this. For all the work involved, there is almost no advantage whatsoever to dig under the drive if the main line is sized properly. If you have to in order to reach an isolated area, that's another story.
- How do I tunnel under drives and walks?
- You can use a pipe on a hose to jab under the cement. Buy an appropriate adapter at the hardware store, and turn the water on when you start jabbing. It may go under easy, especially for a walkway, but drives can be much tougher. Look for an expansion joint that may be wide enough to drop a pipe into, a drain that runs under the drive that can be used to feed a pipe under, or a brick trim that can be pulled up and replaced after the pipe is laid.
- Can I tunnel under asphalt?
- Don't bother tunneling under asphalt. It will just collapse in time and have to be repaired anyway. Dig it up and repair the trench. You may want to use a saw to cut the edges of the asphalt to avoid an uneven cut.
- If I rent a trencher, can it do all of the digging?
- You'll still need to do some digging by hand in tight places or to trim trenches where the trencher didn't cut straight or in the right place.
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