Writing Supplementary Conditions owners need

Every CCDC contract an owner signs is the standard form plus the owner's Supplementary Conditions. The standard form is balanced and familiar to bidders; the Supplementary Conditions are where the owner's own risks get dealt with, or get missed. Many owners inherit a 40-page set from an old project and attach it unread. This lesson shows a better way: start from the owner's risks, put each requirement in the right document, write it in the format the industry expects, and test it against the statute before tender.

Learning outcomes

• Decide whether an owner requirement belongs in the Agreement, a Supplementary Condition, Division 01 or the technical specifications.
• Write a Supplementary Condition in the standard amend, delete-and-replace or add format, keeping the CCDC numbering intact.
• Test a draft against the Construction Act, the rest of the contract and the tender market.
• Outline a short, defensible set of owner Supplementary Conditions for Northgate.

The lesson

Fewer, better conditions

Lesson 5 showed where Supplementary Conditions sit in a CCDC contract and how they rank. Lesson 6 showed which old conditions the 2020 edition made obsolete. This lesson is about writing them.

The Ontario Association of Architects gives the starting principle: the standard forms are generally balanced, so use as few Supplementary Conditions as possible, because bidders react badly to many departures from accepted standards. Every condition that shifts risk to the contractor has a price, paid in higher bids, fewer bidders or a fight later. A good owner set is short, aimed at real project risks, and easy for the Consultant to administer.

Start from the owner's risks, not a precedent file

List what the owner actually needs from this project: the dates that matter, the money it can and cannot absorb, the operations it has to protect, the lender's or insurer's requirements. For each item, ask three questions. Does the standard form already handle it? If yes, leave it alone. Is the form silent? Then add something. Does the form handle it in a way that does not fit this project? Then amend it, as narrowly as possible.

The silent spots are often the most important. McLennan Ross points out three in CCDC 2-2020: the 2008 contract security condition was removed, so an owner that wants bonds must ask for them; the form does not deal with non-statutory holdbacks such as a deficiency holdback; and it does not require the contractor to tell subcontractors when a payment application is rejected or reduced. Each is a gap an owner may need to close.

Put each requirement in the right place

Not every owner requirement is a Supplementary Condition. Figure 1 is a simple sorting test. Changes to the Agreement articles or the Definitions should be issued as amendments under their own titles: the OAA notes that a change to an article or a definition buried in the Supplementary Conditions takes only Supplementary Conditions priority, which can create conflicts. Procedures, such as submittal formats, meeting cadence or scheduling software, belong in Division 01. Technical requirements belong in the specifications.

Division 01 needs a word of caution. CCDC 2-2020 does not assume that Division 01 is part of the contract. If the owner's Division 01 is not incorporated, matters the form expects it to cover may need to come back through Supplementary Conditions. If it is incorporated, read it against the conditions so nothing is said twice in different words.

Write it in the format people expect

Consultants, contractors and lawyers read Supplementary Conditions in a familiar format, used by the OAA and Ontario General Contractors Association's recommended set for CCDC 2-2020. Each item is keyed to the Article or GC it touches. Each starts with an operative instruction: amend, delete and replace, or add. Deleted paragraphs keep their numbers, marked as not used, so every cross-reference in the form still points to the right place. New paragraphs take the next free number. Figure 2 dissects one example: a new contract security condition, which CCDC 2-2020 no longer has.

Plain drafting habits help too. Use the form's defined terms exactly; a "General Contractor" or "Architect" in a CCDC 2-2020 condition is a term the contract does not define. Write one obligation per paragraph. Say who acts, what they deliver, and by when. Avoid "to the satisfaction of the Owner" where an objective test is possible, because the Consultant has to administer the clause and a court may have to apply it.

The statute sets the floor

Some things no Supplementary Condition can do in Ontario. Section 4 of the Construction Act makes void any agreement that the Act does not apply to a supplier, or that its remedies are not available. Under the prompt payment rules, a contract cannot make the giving of a proper invoice depend on prior certification by a payment certifier or prior owner approval. The 10% holdback in section 22 is mandatory. The Act lists the matters a party may refer to adjudication, and the parties can add to that list but should not try to remove it. Conditions that still require consultant certification before an invoice counts, or that try to delete adjudication, need a construction lawyer's review before they go out again. Since January 1, 2026, an invoice is also deemed proper unless the owner gives written notice of what is missing within seven days, and adjudication can start up to 90 days after the contract is completed.

The 2026 amendments raised the stakes again. Contracts entered into on or after January 1, 2026 need annual holdback release, as lesson 7 explained. Any payment condition drafted before then needs a fresh look.

Test every draft before tender

Run each condition through six questions:

1. Need. Does the standard form already do this?
2. Law. Does it conflict with the Construction Act, the Occupational Health and Safety Act or another statute?
3. Fit. Does it break a definition, a cross-reference or the insurance requirements in CCDC 41?
4. Administration. Can the Consultant administer it, and is that in the Consultant's agreement? CCDC's Bulletin 29 makes the point for tariff adjustments: if the owner wants the Consultant to process them, the Consultant's fee should reflect it.
5. Market. Will bidders price it, qualify it or walk away?
6. Proof. If it is breached, can the owner prove it from site records?

Two sources make good starting points. The OAA-OGCA Recommended Supplementary Conditions for CCDC 2-2020, issued in September 2021 and revised in March 2024, are an industry consensus baseline that contractors already accept. Public owners' published sets show the range of what owners ask for. One Ontario school board's 2022 set, for example, requires the schedule in native Oracle Primavera P6 or Microsoft Project format with a critical path analysis on request, and bonds of at least 50% of the Contract Price. Use precedents for ideas, but draft for your project.

Northgate worked example

Northgate Distribution Centre (fictional) is a 12,000 m² tilt-up warehouse in Vaughan, built for Northgate Logistics Inc. (fictional) under CCDC 2-2020 with the owner's Supplementary Conditions. Halvorsen Builders Ltd. (fictional) is the contractor, and Ridgeline Architects Inc. (fictional) is the Consultant under OAA 600. The Contract Price is $34,950,000 and Ready-for-Takeover is planned for Friday January 14, 2028 (M9), with the owner's racking contractor starting Monday January 17, 2028 (M10). See the Northgate fact sheet.

The fact sheet says the owner's Supplementary Conditions exist but not what they contain. Figure 3 is an illustrative outline built from Northgate's risks, using the sorting test and the six questions. It is deliberately short.

Drafting one item: the schedule

Northgate's owner keeps its master schedule in Microsoft Project desktop; Halvorsen schedules in Oracle Primavera P6 and submits XER files. The owner's real risk is not that Halvorsen lacks a schedule. It is that the owner's representative cannot rely on what it receives. So the Supplementary Condition stays short: it amends the construction schedule condition in Part 3 to require a critical path schedule, monthly updates as of an agreed status date, and native files with each update, and it points to Division 01 for the detail. Division 01 (Section 01 32 16, Construction Progress Schedule) then sets the procedure: calendars matching the Mon–Fri, 8-hour, Ontario-holiday work week, the XER file and a PDF with each update, a narrative of changes to logic, and the turnaround time for the owner's review. The legal obligation is in the condition; the procedure is in Division 01; neither says the same thing twice.

One item left out

The owner was tempted to add a condition requiring Ridgeline to certify each invoice before it counts as received. It failed question 2: under Ontario's prompt payment rules a contract cannot make a proper invoice conditional on prior certification. The owner instead adds a Proper Invoice definition that lists the backup each invoice must include, and has Ridgeline check each invoice for completeness within seven days and review its content within the 14-day notice window.

Owner's move

• Write a one-page risk list first. Every condition should trace back to a line on it.
• Start from the OAA-OGCA set. Adopt it where it suits you, then add only what your project needs.
• Keep law in the conditions and procedure in Division 01. Then check the two do not overlap.
• Have a construction lawyer review the set. Especially payment, holdback and adjudication, which the statute controls.
• Brief bidders. Issue the set with the tender, and review significant changes again at the pre-construction meeting.

Common mistakes

1. Attaching an old set unread. Conditions written for CCDC 2-2008 can point to clauses that no longer exist.
2. Changing a definition inside the conditions. It takes only Supplementary Conditions priority and can conflict with the Definitions.
3. Contracting out of the Construction Act. Prompt payment, holdback and adjudication rules apply regardless.
4. Using terms the form does not define. "Architect", "GC" or "Substantial Completion" create ambiguity.
5. Writing duties nobody can administer. If the Consultant's agreement does not cover it, it will not be done.

Quick quiz

1. An owner wants weekly three-week look-ahead schedules in a set format. Where does this belong?

   1. Agreement
   2. Definitions
   3. Division 01
   4. A new GC

2. Why is adding contract security a common owner Supplementary Condition for CCDC 2-2020?

   1. The 2020 form requires 100% bonds
   2. The 2008 contract security condition was removed
   3. The Construction Act requires bonds
   4. CCDC 41 covers bonds

3. When a Supplementary Condition deletes a paragraph, what happens to its number?

   1. The following paragraphs are renumbered
   2. It is kept and marked as not used
   3. It moves to Division 01
   4. It is reused for the next new paragraph

4. Which of these can an Ontario owner validly add by Supplementary Condition?

   1. A requirement that invoices count only once certified
   2. A deletion of adjudication
   3. A Proper Invoice definition listing the backup required
   4. A 5% holdback instead of 10%

5. According to OAA guidance, what is the risk of many departures from the standard form?

   1. The contract becomes void
   2. Bidders react poorly to them
   3. The Consultant must re-seal the form
   4. Liens expire sooner

Show answers and explanations

1. C. It is a procedure, so it belongs in Division 01.
2. B. CCDC 2-2020 dropped the contract security condition, so owners who want bonds must add it.
3. B. Keeping the number, marked as not used, preserves every cross-reference in the form.
4. C. The Act lets the contract specify proper invoice content; it does not allow prior certification as a condition, removal of adjudication or a lower holdback.
5. B. The OAA notes that bidders react poorly to many departures from accepted standards, so use as few as possible.

Key terms

Supplementary Conditions

The owner's project-specific amendments and additions to a standard form's General Conditions.

Operative instruction

The opening words of a condition that say whether it amends, deletes and replaces, or adds text.

Division 01

The General Requirements section of the specifications, for procedures and administration; CCDC publishes a master specification for it.

Contract security

Bonds or other security the contractor gives the owner, such as performance and labour and material payment bonds.

Proper invoice

An invoice that meets the Construction Act's content rules plus any further content the contract requires; it starts the payment clock.

Precedent set

An existing set of conditions used as a starting point, such as the OAA-OGCA recommended set.

References

1. Ontario Association of Architects, Supplementary Conditions (practice advisory, May 2020).
2. OAA and OGCA, Recommended Supplementary Conditions for CCDC 2-2020 (September 2021, revised March 2024).
3. McLennan Ross LLP, The new CCDC 2: Part II, Supplementary Conditions (January 2022).
4. Thompson Dorfman Sweatman LLP, Building success: the importance of legal review of CCDC contracts (October 2024).
5. Toronto District School Board, Supplementary Conditions for CCDC 2 (2020) (July 2022; example of a public owner set).
6. CCDC, Bulletin 29: Adjustments in Contract Price due to tariffs (August 2025).
7. Consolidated Construction Act, industry-hosted consolidation (ss. 4, 13.5, 22 and the prompt payment rules; check against e-Laws).
8. CCDC, Documents (CCDC 01-2020 Division 01 master specification, CCDC 41-2020 and bond forms).
9. Fasken, Ontario's amendments to the Construction Act take effect January 1, 2026 (December 2025).

Verified on November 6, 2026.

Next lesson in this trackCCDC 5A-2025: CM for services