Setting Fence Posts in Rock in Middle Tennessee: What It Really Costs

Rock is everywhere in Middle Tennessee: Davidson, Robertson, Wilson, Smith, DeKalb, every county around here. Some areas have more and some have less, but there's no telling where you'll hit it. A yard that looks like it couldn't possibly have rock can turn up limestone 3 inches down. Nobody can know until we start digging the hole, not me and not any other fence company.

Here's how we handle it so neither of us gets surprised.

What happens when we hit rock

1. Most holes go in fine. Lots of jobs never hit rock that matters.
2. Small rock and chunks we break out with a bar and keep going. No extra charge.
3. A big rock in the way? Sometimes we can shift the post a few inches to one side or the other and miss it. That saves you money and saves us a lot of labor, and if shifting the post works, there's no rock charge.
4. Solid ledge rock means bringing in a rock drill or core bit. That takes extra equipment, fuel and time.

Our rock clause: shown at $0, capped in writing

Some contractors pad every bid for rock "just in case," so everybody pays for rock whether they have it or not. Others leave it off and hit you with a surprise bill. We do neither.

• Your estimate shows rock at $0.00.
• If we hit solid rock that has to be drilled, it's $350 (equipment, fuel, transport) plus $25 a hole.
• It's capped in writing for your job before we start, so you know the worst case on day one.
• We show you and get your OK before we drill.
• Any rock charge is settled at the end of the job, on the final invoice.

That way you only pay for rock if you actually have it, and you never pay more than the cap.

Two things to watch for

When a contractor says they don't charge extra for rock, that should be a red flag. Any company that has more labor put on its business has to charge for it. Use common sense. If they aren't charging extra for rock, one of two things is happening:

1. They dig until they hit rock, then set your post shallow. That means your fence is going to lean.
2. They're rolling the price of rock into your fence and hiding it from you.

Every company has to charge for rock to stay in business.

Why it's worth doing right

A post sitting on top of rock with 8 inches of dirt around it will lean the first time a storm hits a privacy fence. Drilling into the rock and setting the post in concrete gives you a fence that's still straight in 15 years.

Got a rocky yard, or wondering if you have one? Call me. I've been digging in this ground for 34 years.