How Much Does an Architect Cost in Sussex, Surrey & Kent in 2026?

If you're planning a home renovation, extension, or new build in Sussex, Surrey or Kent, one of the first questions you'll want answered is: how much does an architect actually cost? Fees vary considerably depending on the scale and complexity of the project, the fee structure used, and the level of service provided. In this guide, we break down what to expect from architect fees in the South East in 2026, so you can budget with confidence.

How Architect Fees Are Structured

Architects in the UK typically charge in one of three ways: a percentage of the construction cost, a fixed fee, or an hourly rate. Percentage-based fees are common on larger or more complex projects and usually range from around 8% to 15% of the build cost, depending on the scope of service. Fixed fees are often used for smaller, well-defined projects such as single-storey extensions or loft conversions, giving clients cost certainty from the outset. Hourly rates tend to be reserved for smaller advisory pieces of work, such as a planning feasibility study or a single consultation.

Detailed floor plans are produced during the design stage, a key driver of architect fees

What Influences the Cost of an Architect

Several factors affect how much you'll pay for architectural services. The size and complexity of the project is the most obvious driver, but the level of service you require also matters. A full service, from initial concept through to overseeing the build on site, will cost more than a project where the architect is only engaged for planning drawings. The condition of the existing building, whether the property is listed or in a conservation area, and how many design revisions are needed can all add to the overall fee.

Detailed technical drawings prepared for Building Regulations approval form part of an architect's fee

Average Architect Fees by Project Type in 2026

While every project is different, it helps to have a sense of typical costs. A single-storey rear extension might see architect fees ranging from roughly £2,500 to £6,000, depending on the size and whether a full planning application is required. A double-storey extension or significant reconfiguration is likely to fall between £5,000 and £12,000. Loft conversions, which are often simpler in scope, typically range from £1,500 to £4,000. For a full self-build or substantial new-build project, percentage-based fees can mean architect costs of anywhere from £15,000 upwards, reflecting the far greater level of design and oversight involved.

These figures are a general guide rather than a fixed price list. The best way to get an accurate cost for your project is to arrange an initial consultation, during which an architect can assess your brief and provide a tailored fee proposal.

Build costs and material choices directly affect the overall project budget, including architect fees

What's Included in an Architect's Fee

Architect fees are usually broken down into work stages, following the RIBA Plan of Work. This typically includes an initial feasibility study, concept design, developed design, and the preparation of drawings for a planning application. Many clients choose to engage an architect for these early stages only, then bring in a separate professional or use a design-and-build contractor for construction. Others prefer a full service that includes technical drawings for Building Regulations approval and contract administration during the build itself.

Contract administration during the build phase is often charged as a separate service

Additional Costs to Budget For

Architect fees are only one part of the overall project budget. You should also allow for planning application fees payable to your local authority, a structural engineer's fee if the project involves removing walls or adding significant loads, and Building Regulations application fees. If your project needs Party Wall Act consent, a Party Wall surveyor's fee should also be factored in. Depending on the complexity of the site, you may also need a topographical survey or a soil investigation.

Regional Considerations Across Sussex, Surrey and Kent

Planning requirements and typical costs can vary between local authorities, even within a relatively small geographic area. Sussex, Surrey and Kent each include a mix of conservation areas, Areas of Outstanding Natural Beauty, and green belt land, all of which can affect the complexity, and therefore the cost, of a planning application. Working with an architect who understands the specific planning policies of your local council can help avoid delays and unnecessary revisions, which in turn helps keep costs under control.

A West Sussex extension project — local planning requirements can affect overall costs

Getting the Best Value from Your Architect

The cheapest quote isn't always the best value. A well-briefed architect who understands your goals from the outset can save you money in the long run, by designing a scheme that's more likely to gain planning permission first time, and by producing clear, buildable drawings that reduce the risk of costly changes once construction is underway. When comparing quotes, ask exactly what's included at each stage, so you can compare like for like.

Existing and proposed drawings are essential for a planning permission application

Ready to find out what your project might cost? Contact Karenna Wilford Architects for a tailored fee proposal for your home in Sussex, Surrey or Kent.