Site Appraisal Support for Architects: RIBA Stage 0 / Stage 1 Briefing (2026 UK Guide)

A desktop site appraisal is a fixed-fee, 48-hour evidence pack covering planning policy, designations, flood, ground, ecology, heritage, access, and policy levies for a defined red line. It is the constraint layer that sits underneath RIBA Stage 0 (Strategic Definition) and Stage 1 (Preparation and Briefing), before the architect commits to concept design.

For the architect, the value is appointment protection. A constraint-led brief means concept design starts inside a known envelope, the client conversation at Stage 1 is evidenced rather than aspirational, and Stage 2 rework risk on the architect's fee margin drops sharply. It also gives the architect a quotable site appraisal output to attach to the Stage 0 / Stage 1 deliverables under the RIBA Plan of Work 2020.

PF & Co Site Intelligence provides that desktop layer across eight constraint domains, with overlay maps, traffic-light flags, an indicative scheme envelope, and a costed schedule of any specialist studies the evidence triggers. Architects can commission on the client's behalf as a disbursement, or refer the client to order directly.

Order a Site Appraisal or see a sample Site Intelligence report.

The RIBA Plan of Work 2020 is explicit about what each early stage produces. Stage 0 (Strategic Definition) calls for the client business case, project risks, a site appraisal, and a project programme outline. Stage 1 (Preparation and Briefing) calls for the project brief, feasibility studies, site information, and the project execution plan.

The site appraisal at Stage 0, and the site information at Stage 1, are evidence-led documents. Architects often contribute to or produce parts of this material depending on appointment scope, but the underlying constraint evidence (designations, flood, ground, ecology, heritage, infrastructure, policy levies) is sourced from public datasets and specialist databases. The architect's design judgement is added on top.

Where this evidence is missing or thin, the architect has two options. Move into Stage 2 concept design carrying scope risk for whatever surfaces later. Or ask the client to commission a series of specialist desktop studies serially across four to eight weeks, often £1,500 to £3,000 in aggregate before any design conversation begins. A single integrated desktop pack consolidates that evidence into a 48-hour turnaround.

See our site feasibility study guide for how that feeds Stage 1 feasibility output.

This is a commercial argument. Designing into untested constraints carries three real costs that often fall on the architect's fee margin.

First, rework. Concept design produced before constraint evidence has to be re-cut when constraints surface at pre-app or validation. Most appointments allow some additional services or variations, but recovering the full cost of a re-issued concept package is rarely clean, and the downstream coordination effort moves with it.

Second, scope creep. The client comes back at Stage 2 asking why nobody flagged the Coal Authority CMRA trigger, the Flood Zone 3a position, or the Conservation Area issue. The architect inherits a planning conversation that was never in the appointment, and from the client's seat it looks like something the design team should have surfaced.

Third, brief drift. Without policy and constraint evidence, the brief drifts toward what the client wants rather than what the site allows. The corrective conversation at Stage 1 or Stage 2 erodes trust. The architect ends up renegotiating the brief instead of designing into it.

The fix in each case is the same. Front-load the desktop site evidence at Stage 0, brief the client off it, and design Stage 2 onward into a known envelope. That envelope addresses the tilted balance position at NPPF paragraph 11(d), the grey belt tests at NPPF paragraphs 154 to 155 where Green Belt is in play, and sequential test triggers under NPPF paragraph 174 on flood, before a single line is drawn.

Eight constraint domains, each formatted for direct use in the Stage 0 / Stage 1 brief.

Each domain comes with overlay maps, a constraint flag (none, watch, material, critical), and a costed line for any specialist study the evidence triggers. See what is included in our 48-hour desktop pack for the full deliverable list.

The desktop appraisal does not produce drawings. It produces the evidence base the architect uses to brief their own concept design and feasibility work.

Public datasets used include Land Registry, the Environment Agency long-term flood risk service via GOV.UK flood guidance, Defra MAGIC, Historic England, Coal Authority, BGS, Ordnance Survey, and the LPA policies map. Bespoke consultancy may layer additional paid datasets, professional judgement, and site-specific modelling on top.

The desktop pack does not replace MRTPI representation, chartered specialist sign-off under PI, or the architect's own design work. It is the evidence layer beneath the architect's design and the planning consultant's submission. Where any specialist study is triggered, the report names it, gives an indicative cost range, and a typical timeline.

For wider context on desktop versus full report costs see our planning report cost benchmark for 2026, and for the buyer-stage workflow see our development land due diligence guide. For the planning-side reports list see what reports you need for planning permission. General planning context is set out at GOV.UK planning permission guidance.

Two practical routes.

Route A: the architect orders on the client's behalf as a disbursement, billed onward at cost or with a small handling margin. The architect manages the brief, controls timing, and the appraisal lands in their inbox alongside the client's fee proposal. This works well where the architect is lead consultant and wants to set the evidence agenda before any other design team member is appointed.

Route B: the architect refers the client to the order page. The client pays directly and the appraisal output reaches the architect via the client. This works well where the architect prefers a clean fee structure with no disbursements on their invoice, or where the client has a procurement preference for paying suppliers directly.

> Disbursement, Stage 0 site appraisal evidence pack: £199 to £399 plus VAT, payable to PF & Co Site Intelligence and recharged at cost. Deliverable: 48-hour desktop site appraisal across eight constraint domains, used to inform the Stage 0 site appraisal and Stage 1 project brief deliverables under the RIBA Plan of Work 2020. The evidence pack is a desktop screening only. It does not constitute MRTPI planning advice, chartered specialist sign-off under PI, or the architect's own feasibility study. Where the pack identifies a triggered specialist study, the cost and timeline of that study is indicative and additional.

Before commissioning, the architect confirms in writing: red-line boundary, intended use, dwelling count or floorspace, client approval to proceed at the quoted fee, and acknowledgement of the desktop scope limits above. This is the architect's professional duty under the ARB Code and RIBA Code of Professional Conduct: identify the brief, scope it, evidence it, and disclose limits.

The architect is not the author of the desktop pack and does not adopt its conclusions under their own PI. The pack is third-party desktop evidence used to inform the architect's brief and feasibility output. Architects relying on the pack should record this position in the appointment correspondence.

The buying flow is straightforward. Postcode and red-line boundary, intended use, dwelling count or floorspace, fixed quote at scope confirmation, payment, 48-hour delivery. See the architect site appraisal main page for the architect-specific brief format.

The dual-page workflow has two parts. The architect-facing page (this one) sets out the briefing logic, the RIBA mapping, and the appointment-protection argument. The order page (/for-developers) handles the commercial transaction. The architect uses this page to brief the client; the client (or the architect on their behalf) uses the order page to commission. Five scenarios where the desktop pack carries the most weight in the architect's appointment.

One, heritage-sensitive infill. Conservation Area position and listed building setting issues need evidence in the architect's brief before any concept design begins. Two, Green Belt or grey belt sites where the planning route is the question, not the design. Three, brownfield or coal-impacted sites where ground conditions can change scheme economics. Four, Flood Zone 2 / 3 sites where the sequential test or exception test affects layout and finished floor levels. Five, multi-site portfolio briefs where the client is comparing 3 to 5 sites and needs the architect to advise on which to pursue.

Across all five, the desktop appraisal at £199 to £399 sits ahead of architect concept design fees of £20,000 to £50,000. Front-loading the constraint evidence is cheap insurance against rework on the architect's appointment.

For architects briefing concept design at RIBA Stage 0 or Stage 1 on UK projects, the desktop site appraisal at £199 to £399 in 48 hours is the constraint-led evidence layer. It briefs the design start, sharpens the client conversation and protects the architect's appointment scope from rework.

Four-pack price ladder: £199 to validate the brief. £895 for the feasibility upgrade. £1,995 for pre-app preparation. Tailored to submit alongside the architect drawings.

Order a Site Appraisal · See a sample report