How to Compare Architect Proposals Fairly

You've shortlisted three or four architects, had initial conversations, and now the fee proposals have arrived. They look completely different from one another — different formats, different fee structures, different levels of detail. How do you compare them fairly?

This is one of the most common challenges homeowners face, and getting it wrong can mean choosing on price alone, which rarely ends well. Here's how to read, understand, and compare architect proposals for residential projects in London.

Understand the Three Common Fee Structures

Architects in the UK typically charge in one of three ways, and you may receive proposals using different models, making direct comparison tricky.

Percentage of construction cost is the traditional approach. The architect's fee is calculated as a percentage of the final build cost — typically 8–15% for residential projects in London, depending on complexity and the extent of services. The advantage is simplicity. The disadvantage is that the fee rises if costs increase, which can feel like a misaligned incentive (though in practice, cost increases usually mean more work for the architect too).

Fixed (lump sum) fee is increasingly popular for residential work. The architect quotes a total fee for a defined scope of work, often broken into stages. This gives you cost certainty, but the scope must be clearly defined — if you change what you want midway through, expect the fee to be renegotiated.

Hourly or time-based charging is less common for full project commissions but sometimes used for initial feasibility studies or for work where the scope is genuinely uncertain. Rates for experienced residential architects in London typically range from £90 to £200 per hour, depending on seniority and practice overheads.

None of these structures is inherently better. What matters is that you understand which model each architect has proposed and what it includes.

Check What's Actually Included

This is where proposals diverge most — and where homeowners most frequently get caught out. An architect's fee can cover anything from a simple sketch scheme to full project management through construction. The RIBA Plan of Work defines eight stages (0–7), and not every proposal covers all of them.

At minimum, clarify whether each proposal includes:

• Feasibility and brief development (RIBA Stage 0–1) — initial studies, site analysis, and confirming what's possible.
• Concept and developed design (RIBA Stages 2–3) — the creative design work, iterating layouts, elevations, and materials.
• Planning application (typically within Stage 3) — preparing and submitting the statutory application, including any heritage or conservation area considerations.
• Technical design and specification (RIBA Stage 4) — the detailed construction drawings, structural coordination, and specification documents needed to build and to get competitive tender prices.
• Tender and contractor selection (RIBA Stage 4–5) — helping you find, evaluate, and appoint a builder.
• Construction stage services (RIBA Stages 5–6) — site visits, issuing instructions, reviewing work, certifying interim payments, and overseeing practical completion.
• Post-completion (RIBA Stage 7) — snagging inspections, final certification, and defects period monitoring.

A proposal that covers Stages 0–3 only will naturally be cheaper than one covering 0–7, but you'll need to appoint someone else (or pay extra) for the later stages. Make sure you're comparing like with like.

Look at What's Excluded

Exclusions deserve as much attention as inclusions. Common items excluded from architect fees include:

• Structural engineer's fees — almost always separate and typically £3,000–£8,000 for residential London projects depending on complexity.
• Party wall surveyor fees — required if your project affects shared walls with neighbours, common in terraced and semi-detached properties.
• Planning application fees — the statutory fee paid to the local authority (separate from the architect's fee for preparing the application).
• Building control fees — either local authority or approved inspector charges.
• Specialist consultants — energy assessors, acoustic engineers, arboriculturists, heritage consultants.
• CDM (Construction Design and Management) compliance — the principal designer role under health and safety regulations.

If one architect includes structural engineering coordination in their fee and another doesn't, that explains a significant price difference. Always list the exclusions side by side.

Examine the Payment Schedule

How and when you pay matters. Most architects break their fee into stage payments, typically invoiced monthly or at stage completion milestones. A reasonable structure might look like:

• 15–20% at appointment (covering initial feasibility and concept work)
• 25–30% through design development and planning
• 25–30% for technical design and tender
• 15–20% during construction administration
• 5–10% at practical completion

Be wary of proposals front-loading fees heavily — asking for 50% or more before any design work is presented. Equally, understand that architects have significant costs in early design stages, so expecting to pay nothing until planning approval is unreasonable.

Check whether VAT is included or excluded. Most architect practices in London are VAT-registered, so add 20% to any net figure quoted.

What's Normal for Residential London Projects?

Fees vary significantly depending on project scale, complexity, and the architect's experience. As a rough guide for north London residential projects:

• A rear extension and internal reconfiguration of a Victorian terraced house: £15,000–£35,000 for full services (Stages 0–7), on a construction budget of £150,000–£350,000.
• A full house renovation including loft conversion and basement: £40,000–£80,000 for full services, on a construction budget of £400,000–£800,000.
• A new-build house: typically 10–15% of construction cost for full services.

These figures are indicative. Practices with strong reputations, awards, and published work may charge more — and may deliver more value through better design and smoother project delivery.

Red Flags to Watch For

Certain characteristics in a fee proposal should raise concerns:

• No clear scope definition — if the proposal doesn't specify which RIBA stages are covered or what deliverables you'll receive, it's impossible to hold the architect accountable later.
• Unusually low fees — if one proposal is 40% cheaper than the others, something is probably missing. The architect may be underquoting to win the job and then charging extras, or they may simply be inexperienced with this type of project.
• No mention of insurance — professional indemnity insurance should be referenced, including the level of cover. For residential projects in London, a minimum of £500,000 is typical, with £1 million or more for larger schemes.
• Vague timeline — a proposal should include at least an indicative programme showing how long each stage will take. Without this, you have no basis for holding anyone to a schedule.
• No terms of engagement — the proposal should reference or include formal appointment terms (typically based on the RIBA Standard Conditions of Appointment or similar). A handshake agreement is inadequate for a project costing six figures.

Questions to Ask Before You Decide

Once you've reviewed the proposals on paper, go back to each architect with clarifying questions:

1. What specifically is included in your construction stage services? How many site visits? What happens between visits?
2. If the project scope changes during design, how is the fee adjusted?
3. Who in your practice will actually work on my project day-to-day? What's their experience?
4. Can you provide references from recent residential clients in this area?
5. What's your current workload? When could you realistically start?
6. How do you handle disagreements about fees or scope during a project?

The answers will tell you as much about how each architect works as the written proposal does.

Making Your Decision

Price should be a factor, but not the only one — or even the primary one. The architect's fee typically represents 8–15% of total project cost. Choosing a slightly more expensive architect who designs a better building, manages the planning process more effectively, or runs the construction phase more tightly can save multiples of the fee difference.

Look at the whole picture: scope, fee, timeline, experience with your type of project, communication style, and your gut feeling about who you'd trust to manage a complex, stressful, and expensive process on your behalf.

We help homeowners across Hampstead and north London connect with architects whose experience matches their project. Having clear, comparable proposals is one of the best ways to make that choice with confidence.