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.

Change order

What is a change order?

A change order is a written, signed agreement that changes the scope, the price or the schedule of work already under contract. Until it is signed by both sides it is a conversation, and a conversation is not something you can invoice.

Equipment cost per hour

How do you calculate equipment cost per hour?

Add your yearly ownership costs (depreciation, interest, insurance, storage) to your yearly operating costs (fuel, service, wear parts, repairs), then divide by the hours the machine actually works in a year. The last number is the one that catches people: the same machine costs far more an hour at 600 hours than at 1,000.

Certified payroll

What is certified payroll?

Certified payroll is a weekly record of what every worker on a public job was paid, submitted with a signed Statement of Compliance swearing the payroll is correct and that everyone got at least the prevailing wage. It is required on federally funded construction and on most state and local public work.

Directional drilling (HDD)

What is horizontal directional drilling?

Horizontal directional drilling, or HDD, installs pipe along a steerable underground path from one small pit to another, so nothing between the two ends gets dug up. It is how conduit and service lines get under roads, driveways and streams without cutting them open.

Frac-out

What is a frac-out on a directional bore?

A frac-out, also called an inadvertent return, is when drilling fluid escapes the borehole and surfaces somewhere it should not: a lawn, a road shoulder, a wetland or a creek. The fluid itself is usually bentonite clay and water, but a frac-out into a waterway is an environmental incident, not a housekeeping problem.

DR / SDR

What does DR mean on HDPE pipe?

DR, or dimension ratio, is the pipe's outside diameter divided by its wall thickness. A lower DR is a thicker wall. Because it is a ratio rather than a measurement, every size of pipe at the same DR carries the same pressure rating, which is the whole reason the number is printed on the pipe instead of a wall thickness.

Trench box

What is a trench box?

A trench box, also called a shield, is a steel or aluminum structure set in a trench so that if the walls collapse, the box holds the soil off whoever is working inside it. It does not hold the trench open; it protects the space the crew occupies.

Retainage

What is retainage?

Retainage, or retention, is a percentage held back from each progress payment and released after the work is accepted. Five or ten percent is common, so a contractor who has billed $100,000 may have $5,000 to $10,000 sitting unpaid until the end.

Time and materials

What is time and materials work?

Time and materials, or T&M, bills the hours worked, the equipment used and the materials installed at agreed rates, rather than a single fixed price. It moves the risk of the unknown from the contractor to the customer, which is exactly why customers resist it.

Scope of work

What is a scope of work?

A scope of work is the list of tasks on a build, each with a unit and a quantity and nothing about price. It says what gets done and how much of it, so the field, the office and the customer are all working from the same list.

Outside plant (OSP)

What is outside plant (OSP)?

Outside plant, or OSP, is everything in a fiber or telecom network that lives outside the walls of a building: the cable, conduit, poles, handholes, pedestals and splices in the ground and on the poles. It is the construction half of the network, as opposed to the electronics inside.

Pay item

What is a pay item?

A pay item is a single line of work that gets billed by the unit: a description, a unit such as foot, each, square foot or hour, and a quantity. You are paid the unit price times the quantity you actually install, so the count in the field is what decides the check.

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