What exactly does Appendix B require me to photograph?

Appendix B of Approved Document L Volume 1 requires photographs of six detail categories, per plot:

1. Foundations / substructure — including ground-floor insulation details.
2. External walls — insulation and continuity at key junctions.
3. Roof — insulation at the roof, including at the eaves and any room-in-roof details.
4. Openings — windows and doors: fitting and insulation around them.
5. Airtightness — the details relied on for the dwelling's air permeability.
6. Building services — the installed plant and services evidence.

The rules that apply across all six:

• One photograph per required detail, per plot — a photo of plot 1's wall junction does not evidence plot 2's, however identical the house types.
• Taken before closing up. This is the requirement that catches people out: once a detail is boarded, buried or covered, it can no longer be photographed. Industry reviews of the regime flag details being closed up unphotographed as a known, recurring failure — the practical answer is to photograph as you build, not at the end.
• Geo-located, dated and timed. Location services on, so each image confirms where and when it was taken.
• Filed traceably — clear which plot and which detail each image shows; Approved Document L's example filename format is 'P1/3b'.

The photographs go to your energy assessor and building control, and a copy of the evidence accompanies the signed BREL to the dwelling owner at handover. From March 2027, plots built under the Future Homes Standard have additional details to photograph — see what the 2026 edition adds.

Verified against primary sources 13 July 2026.