Reading a Schedule of Quantities — How Civil Works Are Priced
Updated: Sep 4
A schedule of quantities is the spine of a civil works price. It's the line-by-line breakdown of every measured item on a job, from bulk earthworks down to the last metre of pipe, with a rate against each one. Read it well and you can tell, before a sod is turned, whether a tender is realistic, where the risk sits, and what you'll actually be billed for as the job runs. Read it badly and you sign up to surprises.
We price civil and drainage work across South Auckland and Franklin every week, and we've sat on both sides of the table: tendering to head contractors and developers, and pricing our own subcontract packages. So this isn't theory. It's how a schedule of quantities behaves once the diggers are on site and someone has to measure what was built against what was priced. If you're a developer, a builder, a project manager or a head contractor reading a civil price for the first time, this will help you understand what you're looking at.
The short version: a schedule of quantities turns a drawing into a number, item by item, so that everyone is pricing the same scope and you can compare tenders like for like. The detail is where it earns its keep.
What a schedule of quantities actually is
A schedule of quantities, often shortened to SOQ or just the schedule, is a structured list of the physical work in a contract, broken into discrete items. Each item carries a description, a unit of measure, an estimated quantity, a rate, and an extended total (quantity times rate). Add the totals and you have the contract sum for the measured work.
It does two jobs at once. First, it's a pricing document: every tenderer fills in the same blank schedule, so the developer can compare them on equal footing instead of guessing what each one included. Second, it's a measurement and payment tool: as the work proceeds, the quantities actually built are measured and valued against those same rates, which is how progress claims and variations get worked out. That dual role is why the schedule matters long after the contract is awarded.
On civil jobs the schedule usually follows a recognised method of measurement so that everyone counts the same way. Where a job is let by a large contractor or a council, the consultant will state the method up front. The point of a method of measurement is simple: it removes argument about whether, say, excavation is measured by volume in the ground or by the truckload removed.
How to read a line item
Every line in the schedule is doing more than naming a task. Take a typical drainage item: 'Supply and lay 225mm dia PVC sewer pipe in trench, including bedding and backfill, depth 1.5m to 3.0m, measured per linear metre.' Read it slowly and you can see exactly what's in the rate and what isn't.
Description
The description fixes the scope of the item. It tells you the material (225mm PVC), the use (sewer), the location (in trench), and the inclusions (bedding and backfill). Anything not named is either covered by a separate item or excluded. If 'bedding and backfill' weren't written there, you'd expect those to appear as their own lines, and a price that lumps them in would be reading the schedule differently from one that doesn't. That's how two tenders for the same drawing end up looking miles apart.
Unit of measure
The unit drives everything downstream. Pipework is usually per linear metre; excavation per cubic metre; pavement per square metre; manholes, valves and chambers per number (each); and a handful of items, like establishment or traffic management, as a lump sum or per week. The unit has to match how the work is genuinely controlled on site. Measuring imported fill by the tonne behaves very differently from measuring it by the compacted cubic metre, because of bulking and compaction, and a sharp estimator reads the unit before the rate.
Quantity and rate
The quantity is the consultant's estimate of how much of that item the job needs. The rate is what the contractor will charge per unit. Multiply them and you get the line total. Here's the part newcomers miss: in a remeasured contract, the quantity is provisional. You're paid for what you actually build, at the agreed rate, so if the ground throws up more pipe than the drawing suggested, the rate still holds and the quantity moves. That protects both sides, as long as the rates are honest.
The rates tell you more than the bottom line ever will. A tender can land on a sensible total while hiding a loaded rate on a provisional item the estimator expects to grow. Always read the rates against the quantities, not just the sum at the foot of the page.
Provisional, prime cost and lump sum items
Not every item in a schedule is a firm, measured quantity. Three categories behave differently, and mixing them up is where developers get caught.
Provisional quantities are best estimates that will be remeasured. They're common on civil work because you can't see the ground until you're in it: rock, soft spots, dewatering and unsuitable material are all hard to call from a borehole log. A provisional quantity says, in effect, we'll price the rate now and settle the volume later. The honest way to handle these is a fair rate and a transparent remeasure; we'd rather flag a likely overrun early than bury it.
Provisional sums are amounts the consultant inserts for work that isn't designed yet, a connection to an authority's main, say, where the final detail depends on a third party. The sum is a placeholder. When the scope firms up, it's priced properly and the provisional sum is adjusted out. A prime cost sum works similarly for a supplied item, like a specialist valve, where the supply price is carried as an allowance and the install is priced around it.
Lump sum items are fixed. Establishment, traffic management setup, a temporary works design: these are priced as one figure regardless of small movements in quantity. The risk on a lump sum sits with the contractor, which is why a serious civil firm prices them with its own plant rates and crew costs in mind, not a guess. We run our own traffic management, so when that line is in our schedule it reflects real crews and real signage, not a subcontractor's markup stacked on top.
What's hidden in the rates
A civil rate is never just labour plus material. Built into every unit rate, whether the schedule shows it or not, are plant, productivity, access, disposal, and a share of the contractor's overhead and margin. Understanding what loads a rate tells you whether a price is robust or whether someone has cut a corner that will surface later as a variation or a defect.
Plant and productivity
Earthworks and drainage rates live or die on plant. The size of excavator, the haul distance, whether a job needs a shield for deep trenching, whether dewatering pumps run around the clock: all of it sits inside the rate per cubic metre or per metre. A contractor with the right fleet on hand prices tighter because the machine is matched to the task. Our own fleet runs from 5-tonne to 35-tonne excavators, telehandlers, an articulated transporter for moving plant, a hydro-vac for locating services, and bypass and dewatering pumps, so the rate reflects the actual machine for the actual ground rather than whatever can be hired at short notice.
Disposal, services and safety
Where does the spoil go, and what does the tip charge for it? Are there live services in the corridor that need careful exposure by hydro-excavation before the digger goes near them? Deep trenches mean shoring, which means trench and manhole shields and the labour to set them. None of this always appears as its own line; often it's loaded into the excavation or pipe rate. A price that ignores these isn't cheaper, it's incomplete, and the gap shows up as a claim once work starts.
Compliance and overhead
Drainage that ties into a public network has to be built and tested to standard and signed off by a registered drainlayer. The cost of getting that right, the testing, the as-builts, the inspections, sits in the rates too. So does the contractor's overhead: insurances, supervision, the health and safety system that keeps a crew compliant on a head contractor's site. Our crews are Site Safe trained and competency-assessed to the Construction Safety Council Tier 1 framework, with documented safe operating procedures behind them, and that standard is part of what a credible rate carries.
Why the same drawing produces different prices
Put one set of drawings out to three contractors and you'll get three different totals, sometimes very different. That isn't always because one is dearer. More often it's because they've read the schedule differently, and reading the schedule is exactly the skill this article is about.
One tenderer might assume good ground and price thin excavation rates; another, having worked nearby, allows for rock and dewatering and prices accordingly. One might carry traffic management as a proper lump sum; another buries a token figure and intends to claim the rest later. One reads the pipe item as including bedding; another doesn't and leaves a gap. The cheapest total on the page is frequently the one with the most optimism baked in, and optimism on a civil job gets paid for eventually, usually by the developer through variations.
This is why comparing tenders means comparing the schedules item by item, not just the bottom lines. Look at where the rates cluster and where one is an outlier. Ask why a provisional item is loaded. Check that the same inclusions appear in each price. A contractor who's worked the local ground, as we have across Pukekohe, Papakura, Drury, Takanini, Karaka and out to Pokeno, will price what's really there, and that realism is worth more than a low headline number that won't survive contact with the site.
Reading the schedule before you sign
If you're a developer or builder evaluating a civil price, a short, disciplined read of the schedule will tell you most of what you need to know. Work through it in order.
Check the scope inclusions on the major items. Make sure bedding, backfill, disposal, testing and reinstatement are accounted for somewhere, either in the rates or as their own lines.
Identify every provisional quantity, provisional sum and prime cost sum, and understand what triggers each one. These are where the final cost moves.
Compare unit rates across tenders for the big-ticket items: bulk earthworks, pipework, pavement, manholes. Outliers, high or low, deserve a question.
Confirm the method of measurement is stated and consistent, so quantities are counted the same way by everyone.
Look for what's missing. No traffic management line on a job beside a live road, no dewatering allowance on a deep job near the water table, no establishment item: gaps like these are tomorrow's variations.
Read the lump sums against what they actually have to cover, and ask whether the contractor controls those activities in-house or is passing them down a chain.
Do that and a schedule of quantities stops being a wall of numbers and becomes a map of the job: where the work is, where the risk is, and where a price is honest. That's the whole point of measuring civil work this way.
Frequently asked questions
What's the difference between a schedule of quantities and a quote?
A quote is usually a single figure or a short breakdown for a defined piece of work. A schedule of quantities is a structured, line-by-line measurement of every item on a job, with a unit, quantity and rate against each. The schedule lets a developer compare tenders like for like and lets the work be remeasured and paid as it's actually built, which a one-line quote can't do.
What is a provisional quantity, and will it change my final cost?
A provisional quantity is the consultant's best estimate of an item, like excavation, that genuinely can't be known until work starts. In a remeasured contract you pay for what's actually built at the agreed rate, so yes, the final cost can move up or down as the quantity is measured against reality. The rate is fixed at tender; the volume settles on site. A good contractor flags likely movements early rather than springing them on you.
Why is the cheapest tender not always the best price?
Because a low total often means optimistic assumptions: thin ground, no dewatering, token traffic management, missing inclusions. Those assumptions don't make the work cheaper; they defer the cost to variations and claims once the job is underway. Reading the schedules item by item usually shows where a low price has left gaps that the developer ends up funding later.
Do I need a registered drainlayer for the drainage items?
Yes. Drainage that connects to a public sewer or stormwater network must be installed, tested and certified by a registered drainlayer, and the work has to meet the relevant standards before it's signed off. That cost sits inside the drainage rates. We carry registered drainlayers on our crews, so the certification and as-built side is handled as part of the work, not bolted on afterwards.
Can you price a schedule of quantities for a subdivision or infrastructure job?
Yes. We price and build civil, drainage, subdivision, infrastructure and energy works across South Auckland and Franklin, with a permanent crew in Queenstown as well. We've delivered measured civil packages for head contractors and developers on public and private jobs, so we're used to pricing a schedule, holding our rates through a remeasure, and standing behind the inclusions we've allowed.
Frequently asked questions footer
If you have a civil or drainage package out for pricing and want a schedule read by a contractor who'll actually build it, talk to us. Request a quote or call Darryn Muir on 021 271 0035.
