How testing firms price the work
Every construction materials testing proposal is built from the same three components. Field technician time is billed by the hour, portal to portal or from a set dispatch point, with a minimum charge per visit, often two to four hours, so that a fifteen-minute slump test still covers the technician's trip. Laboratory tests are billed per specimen or per sample at a unit price: one price per concrete cylinder break, one per Proctor curve, one per sieve analysis, one per set of Atterberg limits. Engineering and project management time, for report review, special inspection sign-offs, and meetings, is billed by the hour at a higher rate.
Rates vary by market and by the certifications the technician holds. A field technician certified to ACI Grade I and NICET Level II is a different rate than an uncertified sampler, and specifications that require the former get billed for the former. Nuclear gauge work carries the cost of licensed gauge ownership and is priced accordingly. Travel outside the normal service radius, per diem for out-of-town assignments, and overtime for night pours or Saturday placements are line items, not surprises, on a well-written proposal.
What actually drives the total
The rate sheet gets the attention, but the specification drives the number. Two projects with identical rates can differ by a factor of three in testing cost because one specification requires a set of cylinders per 100 cubic yards and the other per 150, or because one requires a density test per lift per 2,500 square feet and the other per 5,000. A specification that requires full-time special inspection during all concrete placement is a fundamentally different scope than one that requires periodic inspection.
Schedule drives it too. A pad that is placed in four large lifts on consecutive days costs less to test than the same pad placed in ten thin lifts over three weeks, because each lift is a technician visit. Concrete placed in one 400-yard pour costs less to test than the same volume placed in eight 50-yard pours. Testing agencies do not control the schedule, but a contractor who understands this can sequence work to keep testing efficient.
Finally, geology and material quality drive rework testing. A fill source that fails qualification means another round of laboratory tests on the replacement. A lift that fails density is retested. A cylinder that breaks low triggers reserve breaks and, in the worst case, a coring program. None of that is in the base proposal, and a contractor with good material and good compaction practice spends less on testing than one without.
Typical line items and what they cover
The table below is the shape of a materials testing proposal, not a price list — rates vary by market and by year, and anyone quoting a flat number without seeing the specification is guessing. Use it to read a proposal, or to check that one is complete.
| Line item | Billed as | What it covers |
|---|---|---|
| Field technician — concrete | Per hour, minimum per visit | Sampling (C172), slump, air, temperature, unit weight, cylinder casting (C31), cure box pickup |
| Field technician — soils | Per hour, minimum per visit | Nuclear density and moisture (D6938), lift acceptance, daily field report |
| Compressive strength | Per cylinder | Laboratory curing, capping, break (C39), report |
| Flexural strength | Per beam | Laboratory curing and break (C78) |
| Proctor (standard or modified) | Per curve | Moisture-density relationship (D698 / D1557), one per fill source |
| Atterberg limits | Per sample | Liquid limit, plastic limit, PI (D4318) |
| Sieve analysis / minus 200 | Per sample | Gradation (C136 / D6913) and wash (C117 / D1140) |
| Special inspection | Per hour, by inspector certification | Reinforcing steel, formwork, embeds, bolting, welding, masonry — per IBC Chapter 17 schedule |
| Engineering review | Per hour | Report review, low-break evaluation, final letter to the building official |
| Mobilization / travel | Per trip or per mile | Outside normal service area; per diem on out-of-town assignments |
Spot testing versus full-time project testing
Spot testing is what a small project buys: a technician visit per pour, a laboratory test per sample, billed as it happens against a rate sheet. It is the right model when the work is intermittent and the total is small. The risk is that nobody is watching the specification's frequency requirements, and the building official's pre-pour inspection is where the gaps get found.
Full-time project testing is proposed from the plans. The agency reads the specification, counts the concrete quantities and fill lifts, applies the required frequencies, and produces a lump sum or a not-to-exceed number with a schedule of assumed quantities. If the project grows, the proposal has unit rates for the change. This is the right model for anything with structural concrete placed on a schedule, because it puts the testing plan in writing before the first pour and it makes proposals comparable.
When comparing proposals, compare the assumed quantities, not the bottom line. Two proposals at similar rates with a 30 percent difference in price almost always differ in how many tests they assumed, and the lower one will come back as change orders.
How to get a number you can rely on
Send the specification section for testing, usually Division 01 quality requirements plus the concrete and earthwork sections, the geotechnical report, and the plans or at least the concrete and fill quantities. With those, a testing agency can produce a written proposal with a scope, a frequency table, a schedule of rates, and a total. Without them, the most an agency can honestly offer is a rate sheet, and a rate sheet is not a budget.
Ask what certifications the technicians hold and whether they match what the specification and the owner require. Ask how reports are delivered and how fast. Ask what happens on a failed test and whether retesting is included. Those questions separate a testing agency from a body shop, and the answers matter more than a dollar an hour on the rate.
Common questions about testing costs
Who pays for testing, the owner or the contractor?
Under IBC Chapter 17 the owner employs the testing agency for quality-assurance testing and special inspection. Contractor quality-control testing, where the contract requires it, is the contractor's cost. Many contracts assign the owner's testing cost to the contractor as an allowance; read the general conditions.
Is retesting included?
Usually not. A failed density test or a low cylinder generates retests, and those are billed at the unit rates. A proposal should say so.
Can testing be done cheaper with a mobile lab on site?
For large, remote, or high-volume projects, a mobile laboratory on site reduces transport time and speeds results, and the cost is a mobilization fee plus a monthly rate. It rarely pays on a small project; it often pays on a plant, a data center, or a highway job.
Why does the proposal have a minimum per visit?
Because the technician's trip is most of the cost. A fifteen-minute test with an hour of drive each way is a three-hour event, and the minimum reflects that.
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