How to Locate & Mark Boundary Markers Before Building a Fence

A line from a famous Robert Frost poem says, "good fences make good neighbors", but it is equally true that a bad fence can make angry neighbors. That's why if you are interested in building a fence, then you should be extra cautious to locate and mark the boundary lines before starting the project. Otherwise, you may end up having to tear down and rebuild a misplaced fence, which is a costly hit to your pocketbook.

Fortunately, it's a fairly simple process of locating and marking fencing boundary lines; below is how you can inexpensively and easily do it yourself:

Tools and materials needed

  • Metal detector
  • Shovel
  • Wooden stakes
  • Fluorescent flagging tape
  • Mallet or sledge hammer
  • Plot plan for your property

Locate and mark boundary lines

1. Obtain a property plot plan. Plot plans are available from your provincial authority, which is often a tax assessing organization, and may even be available online depending on your province of residence.

A plot plan contains a lot of useful information for homeowners, most importantly the borders of their property. The plan may also include legal descriptions of the property as well as information about adjacent properties. Keep in mind that boundary lines as marked on a plot plan may not be accurate, so never rely on a visual representation of your property line when building a fence.

2. Buy or rent your supplies and tools. Once you have your plot plan in hand, you can obtain the necessary tools and materials for the job. Below are a few considerations to keep in mind when obtaining certain items:

  • Metal detector—You don't need an expensive or sophisticated metal detector for locating boundary markers; a simple machine is usually more-than-capable of finding the marker. A detector with discrimination features may speed up the process by eliminating trash finds such as nails, aluminum cans and other buried wastes, though it isn't a requirement to have one.
  • Wooden stakes—The specific length of the stake isn't particularly vital, though a 50-centimeter stake is an ideal size. Try to choose a length that permits you to hang your flagging tape high enough to avoid being a trip hazard.
  • Flagging tape—This thin plastic material is used for a variety of purposes in construction and can be purchased from hardware and home improvement stores. It is made in various colors, but the best choice for your needs is fluorescent orange, yellow or green. You probably won't need more than one or two rolls unless your property's area is large.

3. Search for boundary markers and mark them with stakes. With your plot plan in hand, use your metal detector to search for the boundary markers. The plot plan should guide you to within a meter or so of the markers, and the metal detector will help you locate the exact spot.

Boundary markers consist of long, metal pins driven into the soil. These pins are often a meter in length, and they will usually not be visible at the surface. Once you obtain a possible "hit" on a boundary marker with the detector, dig into the soil until you can visualize the object. As soon as you confirm the object's identity as a boundary marker, drive a wooden stake into the soil directly above or adjacent to the pin. Continue searching for boundary markers with your detector and drive wooden stakes at all pin locations.

4. Flag the stakes. After locating all of the boundary markers and staking them, the next step is to flag the stakes with your flagging tape. Attach the the flagging tape to the first step with a square knot, and string it to the adjacent stake; tie-off the tape to each stake with a square knot.

Keep the tape taut as you pull it from stake to stake, and elevate it above the ground at least 50 centimeters so that it can be easily seen. Be sure not to pull the tape too tight, however, or you may dislodge or move the stakes.