How do I deal with rocks and other underground obstructions?

By far the most frustrating part of installing a fence is running into unforeseen obstacles under the ground. It doesn’t matter if you go the WamBam way or the traditional way- a big rock or tree root is going to cause you grief.

Large Rocks?

If the rock is large and stable enough it may be the perfect foundation to support your fence. We would recommend a technique called core drilling to mount your anchors (illustrated below) or using our surface mount.

B. Excavate dirt to determine how large of a rock you have hit.

C. Use a core drill (a powerful drill designed to drill holes in solid rock). Create a 1-5/8in. to 1-7/8in. diameter hold, anywhere from 6in. to 12in. deep.

D. Fill hole with liquid concrete, or wedge the anchor directly into the hole if it is tight enough to create solid compression.

A. B. Purchase our surface mounts for either vinyl fence or ornamental aluminum fence. Using a hammer drill, create the holes necessary for the anchors. You may want to enlarge the holes on the base plate and use expanding bolts to create a stronger connection than the regular fasteners included.

C. Level surface mount with galvanized washers.

E. For vinyl posts, use the leveling donuts to compensate for any crookedness that still exists in the anchor shaft.

Small Rocks?

Your anchor will penetrate smaller intermittent stones (less than 1 inch) with relative ease. For larger rocks, dig them out of the way much in the same way if you were installing a traditional fence footing. Depending how far they are under the surface will determine if you can backfill with granular material (gravel that will compact) and re-drive your anchor into the ground.

A & B. You may need to excavate and dig out the small rocks to gain penetration.

C. Backfill with material (dirt or gravel) that will compress tightly around the anchor and provide adequate stabilization.

Tree Roots?

The wedge welded on the bottom of the pipe anchor (vinyl only, aluminum pipe anchors do not have this) is designed to slice through tree roots up to about 2in. in diameter. For larger tree roots either relocate the anchor (if possible) or excavate and cut out the section of the offending root.