AIA C401 Architect–Consultant Agreement: flow-down, standard of care, and fee structure

One-line orientation

C401 is the agreement between the architect and a consultant. It aligns the consultant’s duties with the architect’s B101 duties for that discipline. This alignment is called flow-down.

Key points

• Contractual relationship — consultant is bound to the architect:
  • The consultant’s contract is with the architect, not the owner.
  • The owner has no direct contract with the architect’s consultants. Project communication usually follows the architect-consultant chain unless the agreements allow another route. A consultant may still face direct liability to an injured third party.
  • The consultant is an independent contractor (not an employee of the architect).
• Flow-down / incorporation of B101:
  • C401 incorporates the prime agreement (B101) by reference.
  • The consultant’s obligations toward the architect mirror the architect’s obligations toward the owner in the relevant discipline.
  • The consultant must coordinate with the architect and other consultants on the project.
• Standard of care:
  • Consultant must apply professional skill and care at the level of competence ordinarily exercised by professionals in the same field under similar circumstances — the same peer standard as B101.
  • Insurance requirements and service schedules are specified alongside the standard-of-care provisions.
• Scope of services:
  • Aligns the consultant’s work with the phases and standards in the prime agreement (SD through CA).
  • Consultant must respond to RFIs in their discipline and participate in owner-contractor dispute resolution where their scope is involved.
• Additional Services:
  • Consultant notifies the architect when additional services are needed; mirrors the B101 Additional Services mechanism.
• Cost of the Work:
  • Consultant provides cost estimates for their portion of the project and advises on adjustments to scope, quality, or budget.
• Instruments of Service:
  • Grants the architect a license to use the consultant’s work product.
• Compensation:
  • Fee options mirror B101: fixed sum, hourly rates, or percentage-based.
  • Consultant fees are negotiated as part of the architect-consultant agreement.
  • Pay-when-paid:
    • Timing: architect pays promptly after receiving owner payment.
    • Collection duty: architect makes reasonable and diligent collection efforts.
    • Partial payment: consultant receives the same proportional share.
    • Not pay-if-paid: it shifts timing, not ultimate entitlement. C401 itself contains no “reasonable time / pay even if the owner has not paid” override; state law may limit contingent-payment clauses.
• Dispute resolution:
  • Aligns with the prime agreement’s dispute resolution process; includes mediation and arbitration for disputes not involving the owner.

Confusions / comparison

	Prime agreement (B101)	Consultant agreement (C401)
Parties	Owner ↔ Architect	Architect ↔ Consultant
Standard of care	Architect meets peer-level standard	Consultant meets same peer-level standard (flowed down)
Phases covered	SD, DD, CD, Bidding, CA	Same phases, within consultant’s discipline
RFIs	Architect responds to all RFIs	Consultant responds to RFIs in their discipline
Fee basis	Negotiated in B101	Negotiated in C401; payment timing follows the agreement
Dispute resolution	Mediation first, then arbitration/litigation	Mirrors B101; mediation/arbitration for non-owner disputes
Flow-down	Prime document — no flow-up	Incorporates B101; consultant’s duties mirror architect’s

Related

→ pp-aia-document-families (this module): C-series overview and where C401 sits · pp-aia-b101-owner-architect (this module): the prime agreement whose terms flow down into C401 · pp-basic-vs-additional-services (this module): how Additional Services notifications flow through consultant scope.