Finding new-build comparables: the evidence developers actually need

Appraising a new-build scheme with resale evidence alone systematically understates what your homes will achieve — new-build typically carries a premium. But finding genuine new-build comparables is harder than it sounds, and getting it wrong flows straight into your GDV.

The authoritative source: the Land Registry new-build flag

Every sale registered with HM Land Registry carries an Old/New flag — an official Y/N recorded at registration, marking the first sale of a newly built home (and major conversions). This is not inferred or guessed; it's the definitive public record of new-build transactions. A later resale of the same home correctly reads as resale. Filtering evidence to flag = new gives you a clean new-build comp set.

The new-build premium — measure it, don't assume it

Industry rules of thumb put the new-build premium anywhere from 5% to 20%, which is another way of saying rules of thumb are useless. The premium is local: it depends on the resale stock's age and condition, buyer demographics and how much new supply the area has seen. The robust approach: compare HPI-indexed £/sqft of new-build sales vs resale sales within your radius, and use that local ratio. Where new-build evidence is thin, fall back to a conservative default — and say so.

When new-build comps are thin

• Widen the time window and index older sales to today with the UK HPI, rather than widening the radius into a different market.
• Use resale evidence as the base and apply the measured local premium.
• Check neighbouring schemes' sales rates — the pace at which nearby sites sold tells you about depth of demand, not just price.
• Be honest about confidence. A prediction from 12 comps is not as trustworthy as one from 120 — an appraisal that hides this is a liability in front of a lender.

What a complete comp record looks like

Address, sold price, sold date, property type, floor area (so you can compute £/sqft), bedrooms, new-build/resale flag, tenure and distance from your site. Floor areas come from joining Land Registry sales to EPC certificates — the join Threshold has already done for 4.6 million sales across England and Wales.

Data referenced in Threshold is displayed under the Open Government Licence (HM Land Registry Price Paid Data, EPC Register, ONS, UK HPI). All figures produced by Threshold are statistical estimates for site appraisal, not RICS valuations.