The dirt world, explained

Short, straight answers to the questions this work runs on. No jargon, no fluff, written by people who dig for a living.

As-built

What is an as-built?

An as-built is the record of what was actually installed, as opposed to what the plan called for: real depths, real offsets, real materials, captured before the trench is backfilled.

811 / One Call

What is 811, and what happens when you call?

811 is the free national "call before you dig" service. You report where you plan to dig, member utilities send locators to mark their buried lines with paint and flags, and only then is it legal to dig.

Markout colors

What do the utility markout paint colors mean?

Utility marks follow the APWA uniform color code: red for electric, yellow for gas and oil, orange for communications, blue for potable water, green for sewer and drains, purple for reclaimed water, pink for temporary survey, and white for your proposed excavation.

Spoil vs. fill

What's the difference between spoil and fill?

Spoil is the material excavated out of the ground. Fill is material placed and compacted to build grade back up. Spoil can sometimes be reused as fill, but it swells 20 to 30 percent when dug and never all fits back in the hole.

Bank vs. loose yards

What's the difference between bank, loose, and compacted yards?

A bank yard is soil measured undisturbed in the ground. A loose yard is the same soil fluffed up in a pile or truck, roughly 1.2 to 1.3 times bigger. A compacted yard is soil compacted in place, often 0.9 times the bank volume or less.

Markout

What is a utility markout?

A markout is the marking of underground utility lines with paint and flags before digging, performed by utility locators after you open an 811 ticket. Digging legally requires valid, unexpired marks.

Rock clause

What is a rock clause?

A rock clause is contract language that excludes rock removal from the base price and sets a unit price for it if encountered, protecting the contractor from eating an unknowable cost and giving the customer a number instead of a dispute.

Mobilization

What is mobilization?

Mobilization is the cost of getting to work before the work starts: loading and hauling machines to the site, crew travel, setup, and permits. It's a real cost of every job and belongs in every bid, either as its own line or built into the price.

Compaction

What does 95 percent compaction actually mean?

"95 percent compaction" means the fill has been compacted to 95 percent of the soil's maximum dry density as determined by a Proctor test in a lab. An inspector verifies it in the field, usually with a nuclear density gauge.

Select fill

What is select fill?

Select fill is fill material that meets a specification, typically screened or imported granular soil with limited fines and no organics, chosen because it compacts predictably. Common fill is whatever suitable material is available, usually reused native soil.

Pipe bedding

What is pipe bedding?

Bedding is the prepared layer of stone or sand a pipe is laid on, typically 4 to 6 inches, giving the pipe uniform support instead of point loads. The material packed alongside the pipe (haunching) and the layer above it (initial backfill) complete the pipe zone.

Undercut

What is undercutting?

Undercutting means digging deeper than the planned subgrade to remove unsuitable material, soft, wet, organic, or otherwise unstable soil, and replacing it with compactable fill or stone so what's built above doesn't settle.

Frost line

What is the frost line?

The frost line (frost depth) is the maximum depth the ground freezes in a given area. Footings, water lines, and anything that can't tolerate movement or freezing must be placed below it; local code sets the number, roughly 36 to 48 inches in the Northeast.

Toolbox talk

What is a toolbox talk?

A toolbox talk is a short safety meeting, usually five minutes at the truck before work starts, covering one hazard relevant to that day's work. Logged consistently, the talks add up to a documented safety program.

Job costing

What is job costing?

Job costing is tracking every cost, labor hours, materials, equipment time, subs, against a specific job, then comparing the total to what the job billed. It answers the only question that matters at year end: which work actually made money.

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