Last updated: 03/September/2026
Because three separate things depend on it — compliance, the quality of the inspection, and your own exposure.
Compliance is the blunt one: it's mandatory. The RICS Home survey standard lists it among the things members "must" do — "undertake appropriate pre-inspection research to support the service" — and requires that you "must be familiar with the type of property to be inspected and the area in which it is situated". Skip it and you're outside the standard, which is the first thing that gets examined when a complaint lands.
The inspection itself is the practical reason. Knowing before you arrive that the property sits on made ground, in a former mining area, in a surface-water flood zone or inside a conservation area changes what you look at and how hard you look. Cracking in a rear extension reads differently when you already know the ground conditions; a run of unauthorised-looking alterations reads differently when you know there's an Article 4 direction. Desktop research turns a general walk-round into a targeted one, and it's what lets you set findings in the context of the area rather than the four walls.
Then there's risk — yours, both kinds. Professionally, the environmental risks in Appendix C are exactly the ones that surface as claims years later, and a documented research trail is your evidence that a reasonably competent surveyor would have flagged what you flagged. Physically, Surveying safely asks you to "carry out a pre-assessment of the hazards and risks that are likely to be encountered on the visit" before you go — derelict property, contaminated land, lone working — which is desktop research wearing a health-and-safety hat.
And the client sees the difference. A report that explains why this property, in this location, has these specific vulnerabilities is worth paying for; a generic condition list isn't.
Sources: RICS, Home survey standard, 1st edn, November 2019, ss.3, 3.1 and Appendix C; RICS, Surveying safely, 2nd edn, November 2018, s.6.1.