CCDC 4 unit price: quantities and remeasurement

A unit price contract fixes the rate, not the total. The owner's consultant estimates how much fill, pipe or asphalt the job needs, bidders price each unit, and the owner pays for the quantity actually installed. That puts quantity risk with the owner and makes measurement the owner's main control. This lesson walks through CCDC 4-2023, the current unit price form, with a focus on the 15% quantity variation rule and how remeasurement really works on site.

Learning outcomes

• Explain how CCDC 4-2023 turns a Schedule of Prices into an estimated Contract Price and then into a final Contract Price based on measured quantities.
• Apply the quantity variation rule in GC 6.7 to overruns and underruns of more than 15%.
• Describe the measurement and payment cycle under GC 2.2, GC 2.3, GC 5.2 and GC 5.3, including who verifies quantities.
• Spot unbalanced unit prices and set the measurement rules an owner needs before tender.

The lesson

Which edition?

CCDC published CCDC 4-2023, Unit Price Contract, on November 29, 2023, alongside CCDC 2MA-2023 and CCDC 18-2023, replacing CCDC 4-2011. The 2023 edition brings in the CCDC 2-2020 changes: a Ready-for-Takeover milestone (GC 12.1), early occupancy by the owner (GC 12.2), and payment terms aligned with provincial prompt payment law. If your organization still has Supplementary Conditions written for CCDC 4-2011, review them before using them with the 2023 form; the numbering and the takeover provisions have changed. Lesson 7 covers Ready-for-Takeover in detail; it works the same way here.

From Schedule of Prices to Contract Price

The Schedule of Prices lists each item of work, its unit of measure, an estimated quantity and the bidder's Unit Price. Under Article A-4, the quantities are estimates, so the Contract Price written in the Agreement is only an estimated Contract Price: the total of the extended amounts. The definition of Contract Price tells you what the owner really pays: the actual final quantities incorporated in or made necessary by the Work, times the Unit Prices, plus any lump sums and allowances. Figure 1 shows the two calculations side by side.

Two consequences follow. The owner carries the quantity risk: if the estimate is short, the owner pays for the extra quantity at the bid rate. The contractor carries the rate risk: if the unit cost of placing fill turns out higher than it priced, that is its problem, within limits. Unit price contracts therefore suit work whose type is known but whose amount is not: earthworks, site servicing, paving, piling, and other civil work. They are less common for buildings, where a stipulated price on complete drawings is the norm.

The 15% rule in GC 6.7

Big quantity swings break the logic of a unit rate. A rate priced for 18,000 m³ of fill spreads mobilization and fixed costs over that quantity; at 25,000 m³ the contractor earns a windfall on those fixed costs, and at 9,000 m³ it loses money. GC 6.7, Quantity Variations, deals with this. Either party may ask to adjust a Unit Price when the actual quantity differs from the estimate by more than 15%. Figure 2 shows how the adjustment works in each direction.

Three details matter. The adjustment is not automatic: one party has to ask, and the parties negotiate in good faith and record the result in a Change Order. If they cannot agree, the dispute goes to Part 8, and progress payments continue at the unrevised price in the meantime. And the rule protects both sides: the owner can ask for a lower rate on a large overrun, just as the contractor can ask for a higher rate on a large underrun.

How measurement and payment work

CCDC 4-2023 spreads the measurement duties across several general conditions, summarized in Figure 3. The Consultant visits the site to verify quantities wherever Unit Prices are the basis of payment (GC 2.2.2.3). The contractor must tell the Consultant when work is ready to be measured, before it is covered up (GC 2.3.2). Each monthly application values Unit Price work at actual quantities times Unit Prices, and lump sum items in proportion to a schedule of values the contractor submits at least 15 days before the first application (GC 5.2). With each application, the contractor provides the measurements and evidence the Consultant asks for.

The Consultant certifies within 10 days of receiving an application, and the owner pays on or before 28 days after receipt (GC 5.3). Quantities in progress payments are estimates until all the work under that item is finished (GC 5.3.2), so an early overpayment can be corrected later. Late payment carries interest under Article A-5 at 2% above the prime rate for the first 60 days and 4% above prime after that.

Changes, allowances and the method of measurement

A Change Order can be priced from the Unit Prices that apply, or from unit prices derived from them (GC 6.2.2.1). A Change Directive is valued on the actual net change in the contractor's cost plus the fee stated in the contract (GC 6.3). CCDC 4-2023 also keeps a contingency allowance (GC 4.2) alongside cash allowances (GC 4.1); spending from it is authorized and valued through the change provisions.

The form does not tell you how to measure. That belongs in the specifications. Each item needs a stated unit, a method (in place or loose, by survey or by weigh ticket, net or gross of overlaps) and a basis of payment that says what the rate includes. Ontario municipal and provincial specifications are written this way, with separate measurement and payment clauses. A Schedule of Prices with no method of measurement invites a dispute on every invoice.

Unbalanced bids

Because the total is only an estimate, bidders can game it. A bidder who thinks an item is under-estimated prices it high and lowers other items to stay competitive; if it is right, it earns more when the true quantity is paid. Another loads early items to improve its cash flow. Before award, the owner's consultant should compare each unit price with the other bids and its own estimate, and ask the low bidder to explain any outliers. GC 6.7 limits the damage only on swings beyond 15%.

Northgate worked example

Northgate Distribution Centre (fictional) is a 12,000 m² tilt-up warehouse on a 2.6 ha site in Vaughan, owned by Northgate Logistics Inc. (fictional). In reality its site work sits inside the CCDC 2-2020 stipulated price contract with Halvorsen Builders Ltd. (fictional). See the Northgate fact sheet.

What if Northgate's site works had been let under CCDC 4?

Suppose, as a hypothetical, the owner had split the earthworks, storm sewers and paving into a separate CCDC 4-2023 contract, with Ridgeline Architects Inc. (fictional) and its civil subconsultant administering it. The illustrative Schedule of Prices has six items and an estimated Contract Price of $2,770,700. Figure 4 compares the measured quantities with the estimates.

View the data

Item (unit)	Estimated qty	Unit Price	Extended (est.)	Measured qty	% of est.
Topsoil strip (m³)	7,800	$9.00	$70,200	7,600	97%
Engineered fill (m³)	18,000	$28.00	$504,000	22,500	125%
Unsuitable soil removal (m³)	4,000	$45.00	$180,000	2,800	70%
Granular base (t)	21,000	$32.00	$672,000	21,900	104%
Asphalt paving (m²)	26,000	$38.00	$988,000	25,400	98%
Storm sewer (m)	1,150	$310.00	$356,500	1,190	103%
Total			$2,770,700

Applying GC 6.7

Fill overrun. The estimate was 18,000 m³; 115% of it is 20,700 m³. The measured 22,500 m³ leaves 1,800 m³ above the band. The owner asks for a lower rate on that excess, because the contractor's mobilization and compaction set-up are already paid for. The parties agree $24.50 for those 1,800 m³ (illustrative). The first 20,700 m³ stay at $28.00. Fill is paid at $579,600 + $44,100 = $623,700, a $6,300 saving against $630,000 at the bid rate.

Unsuitable soil underrun. The estimate was 4,000 m³ for $180,000; only 2,800 m³ was needed. The contractor asks for a higher rate, because its excavator and trucks were committed for the larger quantity. Under GC 6.7, the new extended amount cannot exceed the original $180,000, so the rate cannot go above $180,000 ÷ 2,800 = $64.29. The parties agree $52.00 (illustrative), so the item is paid at $145,600 instead of $126,000.

Result. At bid rates, the measured quantities total $2,859,300. After the two GC 6.7 adjustments, the final Contract Price is $2,859,300 − $6,300 + $19,600 = $2,872,600, which is $101,900 or 3.7% above the estimate. The owner's representative reports that variance against the owner's contingency, explains it by item, and checks that the fill overrun was a real quantity, not a measurement change: the specification measures fill in place, by survey, not by truck count.

Owner's move

• Invest in the quantity estimate. The owner carries quantity risk; better geotechnical data and a careful take-off pay for themselves.
• Write a method of measurement for every item. Unit, method, and what the rate includes, in the specifications.
• Check bids for unbalanced rates. Compare unit prices across bidders and against the estimate before award.
• Staff the measurement. Make sure the Consultant's fee and site presence cover verifying quantities before work is covered.
• Track the 15% band as the job runs. Flag items heading outside it early, and raise GC 6.7 before the final account, not after.

Common mistakes

1. Reading the A-4 figure as a fixed price. It is an estimate; the owner pays measured quantities.
2. Measuring after the work is buried. Without the GC 2.3.2 notice and a site check, quantities become arguments.
3. Assuming GC 6.7 adjusts automatically. A party has to ask, and the result goes in a Change Order.
4. Repricing the whole overrun. On an overrun, only the quantity above 115% of the estimate gets a new rate.
5. Reusing CCDC 4-2011 Supplementary Conditions. The 2023 form changed takeover and payment provisions.

Quick quiz

1. In CCDC 4-2023, what is the Contract Price written in Article A-4?

   1. A fixed lump sum
   2. An estimate based on the Schedule of Prices quantities
   3. A guaranteed maximum price
   4. The Consultant's budget

2. Estimated quantity 10,000 m³; actual 12,000 m³. Under GC 6.7, how much quantity can get a new Unit Price?

   1. 12,000 m³
   2. 2,000 m³
   3. 500 m³
   4. None

3. An item estimated at 5,000 units at $20 comes in at 3,000 units. What is the highest new Unit Price GC 6.7 allows?

   1. $20.00
   2. $23.00
   3. $33.33
   4. No limit

4. Who verifies quantities where Unit Prices are the basis of payment?

   1. The owner's lender
   2. The contractor alone
   3. The Consultant
   4. The municipality

5. If the parties cannot agree a revised price under GC 6.7, how are progress payments made meanwhile?

   1. They stop
   2. At the unrevised Unit Price
   3. At the contractor's proposed price
   4. At 50% of the Unit Price

Show answers and explanations

1. B. The quantities are estimates, so the A-4 figure is the total of the extended amounts, subject to measurement.
2. C. 115% of 10,000 is 11,500; only the 500 m³ above that can be repriced.
3. C. The new extended amount cannot exceed the original $100,000, so the rate is capped at $100,000 ÷ 3,000 = $33.33.
4. C. GC 2.2.2.3 has the Consultant verify quantities of Unit Price work.
5. B. The dispute goes to Part 8 and progress payments continue at the unrevised price.

Key terms

Unit Price

The amount payable for one unit of an item of Work, as stated in the Schedule of Prices.

Schedule of Prices

The list of items, units of measure, estimated quantities and Unit Prices that forms part of a CCDC 4 contract.

Extended amount

Estimated quantity times Unit Price for one item; the sum of all items is the estimated Contract Price.

Remeasurement

Measuring the actual quantity of each item installed, so payment reflects real quantities rather than estimates.

Quantity variation

Under GC 6.7, a difference of more than 15% between actual and estimated quantity that lets either party ask for a new Unit Price.

Unbalanced bid

A bid that loads some unit prices and lowers others to gain from expected quantity errors or early cash flow.

Method of measurement

The specification rule that says how each item is measured and what its rate includes.

References

1. CCDC, Documents (current editions list: CCDC 4-2023).
2. Ontario Association of Architects, New CCDC contract updates: launch of CCDC 2MA, 4 and 18 (January 2024).
3. WeirFoulds LLP, CCDC 2MA, 4 and 18 (2023): what's new (September 2024).
4. Municipality of Southwest Middlesex, tender Section 5: CCDC 4-2023 Unit Price Contract (September 2024; used to read Articles A-4 and A-5 and GC 2.2, 2.3, 4.2, 5.2, 5.3, 6.2, 6.3 and 6.7).
5. CCDC, CCDC 4 table of contents (earlier edition structure).
6. RAIC, Canadian Handbook of Practice for Architects, chapter 4.1 (unit price contracts and verification of quantities).
7. Consolidated Construction Act, industry-hosted consolidation (prompt payment; check against e-Laws).

Verified on November 6, 2026.

Next lesson in this trackWriting Supplementary Conditions owners need