Who is responsible for co-ordinating design, and can a main contractor be given that responsibility?

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Legal and contractual solutions - Design

Who is responsible for co-ordinating design, and can a main contractor legitimately be given that responsibility even though it has no design responsibility?

The default designer duty and shifting coordination to the contractor

Coordinating the design so its parts fit together is a duty in itself. Whether it rests with the architect or engineer or can be placed on a main contractor turns on the words of the contract.

Quick answer

By default the architect or engineer coordinates the design, and a main contractor takes on coordination only where a full and descriptive clause clearly says so; absent an express design obligation a main contractor does not readily become liable for a subcontractor design or its coordination

By default the architect or engineer is responsible for coordinating the design, because an employer that appoints a designer is entitled to expect it to be responsible for all the design work. A main contractor can be given the coordination role, but only by clear words: a specification that names a subcontractor as coordinator does not relieve the designer, and a brief statement that the contractor coordinates everyone is not enough. To place coordination on a main contractor the contract needs a full clause identifying the trades and stating that the costs of a failure to coordinate fall on the contractor. Absent an express design obligation, a main contractor does not readily pick up liability for a subcontractor's design, particularly where the design was developed between the subcontractor and the design team without the contractor's involvement. On design and build the contractor carries both the design and its coordination.

DefaultThe architect or engineer coordinates the design
Specification naming a subcontractorDoes not relieve the designer of its duty
Shifting to the contractorNeeds a full clause naming the trades and the costs
Main contractorNo implied design or coordination duty absent express words
Design and buildThe contractor carries the design and its coordination
Section 1

The problem

Design coordination, making the many parts of a design work together, is a task in its own right. When specialist subcontractors design parts of the works, someone must ensure the pieces fit. Who is responsible: the architect or engineer, or the main contractor? And can a main contractor be given the job even though it does no design itself?

Section 2

The default designer duty

The default is that the architect or engineer coordinates the design. An employer that appoints a designer is entitled to expect it to be responsible for all the design work, and coordination goes with that, unless the contract clearly says otherwise. The principle that a designer is responsible for the design it was engaged to provide comes from Moresk Cleaners Ltd v Thomas Henwood Hicks. Coordination is part of the designer's duty by default.

Section 3

Shifting coordination takes clear words

Shifting coordination to the contractor takes clear words. A specification that names a subcontractor as responsible for coordination does not, by itself, relieve the architect of its own duty. If a main contractor is to carry coordination, the main contract needs a full and descriptive clause: it should identify the trades involved and state expressly that all costs and losses from a failure to coordinate the subcontractors' design and drawings fall on the main contractor. A brief statement that the contractor coordinates all subcontractors, including design, is not enough.

Section 4

The main contractor's position

Absent an express design obligation, a main contractor does not readily pick up liability for a subcontractor's design.

Norta Wallpapers (Ireland) Ltd v John Sisk & Son (Dublin) Ltd(1977) 14 BLR 49

Roof lights designed by a nominated subcontractor leaked after completion. The employer sought to recover from the main contractor, although the main contract said nothing about the contractor having any design responsibility. On the claim, the Irish Supreme Court held that no design obligation could be implied into the main contract, so the main contractor had no liability. Where design is developed between a subcontractor and the design team without the main contractor's involvement, an implied coordination or design duty on the main contractor is hard to establish.

Section 5

Design and build and modelling

Two modern points shift the picture. On a design-and-build contract the main contractor takes responsibility for the design, and coordination goes with it. And on larger projects, building information modelling gives a three-dimensional model that makes coordination easier and clashes between services less likely, though the contractual responsibility for coordination still rests where the contract puts it, not with the software.

Section 6

Practical steps

1

Start from the default: the architect or engineer coordinates the design unless the contract clearly moves it.

2

To place coordination on the contractor, use a full descriptive clause naming the trades and the costs and losses it covers.

3

Do not rely on a specification naming a subcontractor as coordinator to relieve the designer. It usually will not.

4

On design and build, expect the contractor to carry coordination with the design.

5

As an employer, take a design warranty from a subcontractor whose coordination or design you are relying on.

6

Use a coordinated model where the project justifies it, but keep the contractual responsibility for coordination clearly allocated.

Section 7

Authorities

AuthorityCitationWhat it decides
Moresk Cleaners Ltd v Thomas Henwood Hicks(1966)A designer is responsible for the design it was engaged to provide, including coordination, unless the contract says otherwise
Norta Wallpapers (Ireland) Ltd v John Sisk & Son (Dublin) Ltd(1977) 14 BLR 49No design or coordination obligation is implied on a main contractor for a nominated subcontractor design absent an express term
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Note
This page states the position on the authorities named, as at 13 July 2026. Responsibility for design coordination always depends on the appointment and the contract. This material is provided for educational and professional development purposes only and does not constitute legal advice. Always consult qualified professionals before acting. SCCSI and its contributors accept no liability for reliance on this material.