Before any site is worth designing for, one question decides everything: what constraints sit on it? Consultants call the answer a desktop study. This tool runs one instantly — a single postcode is tested against fourteen official datasets published to the government's planning data platform, from green belt and conservation areas to SSSIs, scheduled monuments, flood zones and AQMAs.
Run your site appraisal
The checker needs JavaScript. The datasets it queries are listed below, all on planning.data.gov.uk.
What gets checked
- Policy designations — green belt, National Landscapes (AONB), national parks, World Heritage Sites.
- Heritage — conservation areas, listed building outlines, scheduled monuments.
- Rights and restrictions — article 4 direction areas (where councils have withdrawn permitted development rights), tree preservation zones.
- Ecology and land — SSSIs, ancient woodland, provisional agricultural land classification.
- Technical triggers — Environment Agency Flood Zones 2/3 and Air Quality Management Areas, feeding straight into our flood and AQMA tools.
How to read the results honestly
Two limits matter. First, this is a point check at your postcode's coordinates — a large site can cross boundaries the point misses. Second, four of the datasets (conservation areas, article 4, listed building outlines, TPO zones) are fed by individual councils and do not yet cover every authority — the tool marks these with an asterisk, and "none found" there is evidence, not proof. National datasets (green belt, SSSI, monuments, flood zones) are effectively complete. For a decision you would spend money on, confirm against the council's own policies map — our council finder takes you straight there.
Why constraints decide applications
Each flag changes your submission list: a conservation area brings design scrutiny and removes PD rights; green belt shifts the burden of justification entirely (see the green belt checker); a flood zone triggers an FRA and the sequential test; an AQMA invites an air quality assessment; article 4 can turn a "no permission needed" extension into a full application (check with the extension PD checker). Knowing all of it in minute one is the difference between a scheme designed around its constraints and one refused by them.
How Fortress Associates can help
Every technical flag this tool raises maps to a report we generate free, in minutes: flood risk assessments, air quality assessments, energy statements and sustainability statements — plus daylight reports for tight urban sites. Build your document list with the checklist generator, or see all tools at /free-tools.
Sources & further reading
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