NZS 3910 §14 and §13 Quote-Check for an Architect in the CA role — Mt Eden villa alterations

Steve Parker
May 30
6 min read

Updated: Jul 9

Mt Eden villa alterations put a NZIA architect in CA in the impartiality pinch — the same client who briefed the design now sees variations. The pre-award read is where the §14 determinations stay clean.

By Steve Parker · Trueworks · NZ construction estimation · 5 min

Mt Eden villa alterations are bread-and-butter work for NZIA architects, and the architect-in-CA role is common. The pinch point is impartiality — the same client who briefed the design now sees the §14 variations land. The pre-award read is where the determinations stay defensible and the client relationship stays intact.

By Steve Parker · Trueworks · NZ construction estimation · 5 min

What you'll learn in this post

The §14 and §13 clauses the architect-CA owns
Three Mt Eden patterns that produce most §14 determinations
A 5-line desk check before you recommend acceptance

Quick answer: A NZIA architect in the CA role under NZS 3910:2023 reads a Mt Eden villa-alteration tender against §14 (variations) and §13 (dispute resolution), against the impartiality requirement at §6.1.1, and against NZIA Practice Notes on the dual role. Three Mt Eden patterns dominate: basement-cut retaining, character-overlay front-elevation, and cross-lease party-wall scope. A 30-minute desk check pre-award keeps determinations defensible and the client relationship intact.

The architect-in-CA arrangement is common on Mt Eden villa alterations. The architect designs, contract-administers, and often holds the longest relationship with the client. The trade-off in that arrangement is the impartiality requirement at §6.1.1 of NZS 3910:2023 — the architect-CA writes §14 determinations that the contractor can dispute under §13, and those determinations need to read as fully reasoned for both sides.

NZIA Practice Notes on the dual role are explicit: the architect can fill both seats, but the determinations need a procedural file behind them.

What §14 and §13 load onto the architect-CA

NZS 3910:2023 names the Engineer to the Contract; the two clauses that surface most often on a Mt Eden architect-CA arrangement:

§14 variations — §14.2 instructs, §14.4 values, §14.5 deals with time, §14.6 administers PC sums. Every variation determination must name the sub-clause.
§13 dispute resolution — escalation pathway if the contractor disagrees with the CA's §14 determination. The architect-CA's reasoning at §14 is the file evidence at §13.

The NZIA Practice Notes on architect-as-CA reinforce that the architect's determinations need to be reasoned, written, and on file. The impartiality requirement at §6.1.1 isn't aspirational — it's the basis on which a §13 dispute will be assessed.

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Three Mt Eden patterns that produce most §14 determinations

1. Basement-cut retaining wall. Most Mt Eden basement additions or rear-extension cuts involve 1.5-2.5 m retaining against a neighbouring boundary. The MBRW/SED detail typically specifies 20-series UNO with 25-series at higher retained sections. Trade quotes priced off the foundation plan alone routinely under-price the 25-series — and the variation lands at first cut. The architect-CA's §14 determination needs to read whether the foundation plan was sufficiently clear, which sits at §6.2 documents hierarchy and feeds §14.2 sub-clause selection.

2. Character-overlay front-elevation cut-ins. Mt Eden's character overlay typically retains identified street-facing fabric — fascia, bargeboard, sash joinery, sometimes the corner-board profile. The carpentry and painting quotes price visible work; the substrate condition behind retained finishes (often rotted lath, sometimes structurally compromised) surfaces at month 3-4 as a §14.2.1.1.d "changed conditions" claim. The architect's design knowledge of the existing fabric is relevant; the impartiality requirement means the determination still needs to reason both sides.

3. Cross-lease party-wall and shared-driveway scope. Mt Eden's cross-lease titles frequently involve shared subfloor, shared rear driveway, and a party wall with the neighbour. Tender documents are often silent on restoration of neighbour-side disturbance. §14 captures the cost; the architect-CA writes the determination. The client relationship complicates this — the client paid for the design and may push back on a variation determination that goes against them.

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A 5-line desk check before recommending acceptance

| # | What to test | Test against | Failure cost | |---|---|---|---| | 1 | Drawing-revision integrity (architect + structural + heritage) | §6.2 documents hierarchy | $5-20k §14 variation | | 2 | Basement-cut retaining scope detailed (20-series vs 25-series) | NZS 4229 §3, MBRW detail | $10-40k §14.4 valuation | | 3 | Character-overlay cut-in and substrate allowance defined | Scope schedule + heritage conditions | $15-50k §14.2.1.1.d argument | | 4 | Cross-lease boundary-side restoration scope named | Scope schedule | $5-25k §14 variation | | 5 | Code references named (NZS 3604, 3404, 4229, E2/AS1) | Trade scope | $5-50k installation-standard dispute |

A 30-minute desk job pre-award.

The architect-CA-specific extras

Two conditions worth pricing into the architect-CA review on Mt Eden. First, the architect's design-stage relationship with the client means the principal often expects the architect to "fight their corner" on §14 determinations — the NZIA Practice Notes are explicit that this isn't the role, and a written client-onboarding memo at appointment time helps. Second, the architect's design knowledge of the existing fabric means a §14.2.1.1.d "changed conditions" determination can be more sharply reasoned — the architect knows what was visible at design stage and what wasn't, which informs whether the conditions are genuinely changed.

FAQ — Architect-CA quote-check for Mt Eden villa alterations

Q1: Does NZS 3910:2023 allow the architect to be both designer and CA on the same project? Yes — §6.1.1 names the Engineer to the Contract as a contractual role that can be filled by an architect, QS, engineer, or principal's representative. The impartiality requirement applies regardless of who fills the role.

Q2: How do NZIA Practice Notes apply to a §14 determination an architect-CA makes against their own design? The Practice Notes are explicit that the dual role is acceptable but requires reasoned, written determinations. If a §14 determination involves a design ambiguity the architect created, that's still the determination to write — and the §13 dispute pathway is the contractor's recourse.

Q3: What's the typical cost of a §14.2.1.1.d "changed conditions" determination on a Mt Eden character-overlay cut-in? $15-50k per cut-in surface, depending on the substrate condition and the visible reinstatement required. Repaints are lower-end; full substrate rebuild is upper-end.

Q4: How does the architect-CA handle a contractor §13 dispute notice on a §14 determination? §13 sets out the escalation — referral to mediation or expert determination depending on the special conditions. The architect-CA's file evidence (drawing revisions, scope schedule, written reasoning) is what gets reviewed.

Q5: What's the most common scope ambiguity on a Mt Eden villa alteration that produces a §14 dispute? The cut-in interface between retained fabric and new structure — particularly where the character overlay retains the street face but the new rear addition cuts into the existing roof and wall structure. The contractor priced the new work; the cut-in surfaces at month 3-4.

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