The short answer
An architect designs the project and, on many jobs, also administers the building contract — issuing instructions, checking the work against the drawings, and certifying payments. A project manager coordinates the delivery: the programme, the budget, the different trades and consultants, and the day-to-day running of the job. The roles overlap, because architects often perform contract administration and informal project oversight under the RIBA Plan of Work, while project managers focus on time, cost and coordination rather than design. On a small domestic project the architect (or the builder) usually covers the management informally and a separate project manager isn't needed. On a large or complex build, a dedicated project manager can add value alongside the architect — they're complementary, not interchangeable.
On bigger projects you'll hear both titles, and it's not always clear where one ends and the other begins. Here's what each role really covers and when you'd want a separate project manager rather than relying on the architect.
Architect vs PM
- ArchitectDesign + contract admin
- Project managerProgramme, cost, coordination
- OverlapBoth manage delivery
- Small projectsArchitect/builder covers it
- Large projectsDedicated PM helps
What the architect's role covers
An architect's job runs from design into delivery, especially on a traditional contract. Beyond designing the building, an architect commonly:
- Produces tender and construction drawings the builder works from.
- Helps you select and appoint a contractor.
- Acts as contract administrator — issuing instructions, inspecting the work for conformity with the drawings, valuing progress and certifying payments, and issuing the certificate of completion.
- Coordinates other consultants such as the structural engineer.
This is all set out in the later stages of the RIBA Plan of Work. So an architect already does a meaningful amount of project oversight — which is why, on smaller jobs, a separate project manager often isn't necessary. What the architect's role does not centre on is the minute-by-minute logistics of the site, which is more the builder's or a project manager's domain.
What a project manager does
A construction project manager focuses on delivery: time, cost and coordination. On a project large enough to warrant one, they typically:
- Develop and police the programme — the sequence and timing of works.
- Manage the budget and cost reporting, often alongside a quantity surveyor.
- Coordinate the many parties — contractors, sub-trades, consultants and suppliers — so the right people are doing the right thing at the right time.
- Handle risk, procurement and reporting back to the client.
The project manager is generally not the designer — they make the agreed design happen efficiently. On complex jobs with many moving parts, that coordination is a full-time role in itself, which is why it gets separated from the architect.
| Aspect | Architect | Project manager |
|---|---|---|
| Primary focus | Design + contract admin | Time, cost, coordination |
| Designs the building | Yes | No |
| Runs the programme | Partly / informally | Yes |
| Certifies payments | Often (as CA) | Sometimes |
| When essential | Most projects | Large/complex builds |
Indicative comparison for guidance only. Sources: RIBA and APM guidance.
Do you need both?
It comes down to the size and complexity of your project:
- On a typical domestic extension, loft or refurbishment, you usually don't need a dedicated project manager. The architect handles design and contract administration, and a competent main contractor coordinates the trades on site. Adding a separate PM can be an unnecessary cost.
- On a large, complex or multi-consultant project — a substantial new build, a project with many specialist trades, or a tight programme — a dedicated project manager can genuinely add value by keeping cost, time and coordination under tight control, freeing the architect to focus on design and contract administration.
The honest bottom line: the roles overlap but aren't the same. An architect already provides design and a good deal of delivery oversight, so for most home projects you don't need a separate project manager. Reserve a dedicated PM for the larger, more complicated builds where coordinating many parties is a job in its own right. If you do use both, agree clearly who is responsible for what — particularly contract administration and cost — so nothing falls between the two.
Frequently asked questions
Does an architect project manage the build?
An architect often acts as contract administrator and provides design-stage oversight under the RIBA Plan of Work — inspecting work, issuing instructions and certifying payments. That's not the same as full construction project management, but on smaller jobs it usually covers what's needed.
Do I need a project manager for a house extension?
Usually not. For a typical extension, the architect handles design and contract administration and the main contractor coordinates the trades. A dedicated project manager is more relevant to large, complex builds with many parties to coordinate.
Can a project manager design my project?
Generally no. A construction project manager focuses on programme, budget and coordination, not design. The design comes from an architect, technologist or designer; the project manager makes the agreed design happen efficiently on time and on budget.
Sources & further reading
Figures on this page are typical UK ranges drawn from published sources and depend on your specific project. They are guidance, not a quotation.