Curing Conflict: Drawings, Specifications, and a Friday Pour
Your firm is the general contractor on a four-story, 1,150-space cast-in-place post-tensioned parking structure. Division 01 Section 01 11 00 establishes this order of precedence: (1) Modifications, (2) Agreement, (3) Addenda, (4) Drawings, (5) Specifications, (6) Schedules. Structural General Note 3 on S-001 reads "Cure all concrete per ACI 308, minimum 7 days." Specification Section 03 30 00 §3.4 requires moist curing of elevated slabs for 7 days. Drawing S-501, Note 4 states "Curing compound permitted on elevated slabs." The post-tensioning supplier has told you that curing compound residue will interfere with the bonded topping the owner's traffic coating requires, and the traffic coating manufacturer will not warrant its product over a compound-cured surface. The concrete subcontractor has priced moist curing as an extra and wants a change order before Friday's pour; the superintendent wants to spray compound and stay on schedule.
1. Apply the order of precedence and determine, with reasoning, which curing requirement governs Friday's pour. Identify any ambiguity the precedence clause does not resolve.
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Start with the precedence clause, then recognize what it does not solve.
By the stated order, Drawings (4) outrank Specifications (5), so S-501 Note 4 - compound permitted - would appear to govern over 03 30 00 §3.4. That is the superficial answer, and it is wrong to stop there.
The real conflict is drawing-to-drawing. S-001 General Note 3 requires curing per ACI 308, minimum 7 days, and ACI 308 governs curing method; it does not authorize compound as a substitute for moist curing on a slab receiving a bonded topping. Two drawing notes at the same precedence level conflict, and the clause is silent on that tie.
Second, cure selection cannot be read in isolation from the finish system. If the traffic coating manufacturer will not warrant over compound residue, permitting compound creates a latent failure in Division 09 that the curing note was never written to address. A conflict "resolved" by precedence that produces a non-conforming finished assembly is not resolved.
Conclusion: do not pour under the compound interpretation. Require moist curing, or a method the topping manufacturer accepts in writing, until the architect answers an RFI. The cost of an RFI is days; the cost of a failed topping warranty is the deck.
2. Write the RFI: state the question, your recommended resolution, and the schedule impact you should disclose. Who must the answer come from and why?
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The RFI must be closed-ended and schedule-aware.
Subject: conflict between S-001 Note 3, S-501 Note 4, and 03 30 00 §3.4 - curing method, elevated slabs.
Question: S-501 Note 4 permits curing compound; S-001 requires curing per ACI 308 and 03 30 00 requires 7-day moist cure. The specified traffic coating manufacturer states it will not warrant over compound-cured concrete. Confirm the required curing method for elevated slabs and confirm compatibility with the topping and traffic coating system.
Recommended resolution: moist cure per 03 30 00 §3.4, or a curing method accepted in writing by the traffic coating manufacturer.
Schedule impact disclosed: elevated deck pour is scheduled Friday; each day of delay pushes the post-tensioning sequence and the topping. State the last date on which an answer preserves the schedule. Do not inflate it; do not hide it.
Who answers: the architect/engineer of record, in writing, through the formal process - not the superintendent, not the concrete subcontractor, not a field verbal. The architect may need to consult the coating manufacturer, so say that in the RFI to keep the review period realistic. Copy the owner's representative so the potential cost is visible before it becomes a claim.
3. The subcontractor says it will proceed with compound under protest. Explain how you protect the owner's and your firm's position, and what cost exposure exists if the interpretation is later reversed.
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Convert a dispute into a controlled record before the concrete goes in the forms.
Do this: issue a written direction stating the curing method the contract requires, reference the RFI, and state that proceeding with compound is the subcontractor's election and at its risk for rework. That sentence is the difference between a change order and a back-charge. Confirm receipt. Notify the owner's representative in writing the same day - the owner must know design intent is unconfirmed. Expressly reserve the owner's right to deduct and your right to back-charge.
Do not: sign a change order for moist curing before entitlement is resolved; allow the pour without a written directive; or accept a verbal "we'll fix it later."
Exposure if the interpretation is reversed in the sub's favor: the moist-curing premium, plus any delay to post-tensioning and topping, plus - if compound was used and the coating later delaminates - scarifying and re-topping an elevated deck. That last number dwarfs the curing premium by an order of magnitude, which is precisely why you hold the pour rather than accept the change order. Recognize that assumption of risk language does not automatically make a disputed direction enforceable; it preserves the record that lets a court or arbitrator decide who carried the risk.