Barn conversion (Class Q)

Class Q PDR up to 10 dwellings, 150sqm cap. Unknown-structure conversions justify 15 percent contingency.

Preset defaults

  • Units: 2
  • GIA per unit: 1,400 sqft
  • NIA ratio: 92%
  • Build cost: 1,950 £/sqm
  • Professional fees: 9%
  • Contingency: 15%
  • s106 / CIL / BNG per unit: £0
  • Finance rate: 10.5%
  • Duration: 12 months
  • Target PoC: 25%

What this preset is for

Class Q PDR up to 10 dwellings, 150sqm cap. Unknown-structure conversions justify 15 percent contingency.

Class Q post-2024

  • Class Q now permits up to 10 dwellings, with a 150 sqm cap per dwelling.
  • 1.5 metre dwelling extension permitted in some cases; check the latest amendment in force.

Build cost realism

  • Barn conversion £1,800 to £2,200/sqm BCIS is a thin band; treat as a floor.
  • Unknown-structure work justifies 15 percent contingency, not 7.5.

Open in workbench

Inputs
MAX LAND BID£245,976At 25% profit on cost, 2 units, 1400 sqft GIA each.
MARGINAL
GDV£1,094,800
Build cost£507,250
Prof fees£45,653
s106/CIL/BNG£0
Contingency£82,935
Finance interest£33,382
Target profit£167,305
Total costs (excl land)£669,220
Senior debt @ LTGDV£711,620
PoC19.6%
PoGDV16.4%
LTC77.8%
Sensitivity (PoC %)
Build -5%Build +5%Build +10%Build +15%Build +20%
GDV -15%22%24%25%21%16%
GDV -10%21%22%23%24%23%
GDV -5%20%21%22%23%24%
GDV 0%19%20%21%22%23%
GDV +5%18%20%20%21%22%

Cells show profit-on-cost percentage at each GDV stress / build-cost shock pair. Cells below your target PoC turn amber-warm; cells below 10 percent abort.

Permitted Development Rights· Class MA and Q currentAppraisal model reviewed by Oliver Wakefield-Smith (data integrity) with chartered-surveyor (MRICS) and CTA tax review. No affiliate links.