_u_brick_thin_wall_age_a_to_e's `<= 280` check put an uninsulated solid-
brick wall of exactly 280mm in the "200 to 280mm -> 1.7" row; RdSAP 10
§5.7 Table 13 (spec PDF p.41) shares 280 as an unlabelled edge between
that row and "280 to 420mm -> 1.4", so the table text alone doesn't say
which row owns it.
Found by building cert 100031768368 (280mm exactly, band C) in Elmhurst
and comparing every worksheet line to the calculator: volume/ACH/floor/
doors matched exactly, but the wall didn't (1.70 vs Elmhurst's 1.40)
despite an identical input crosswalk. Initially reverted a first attempt
at this fix when it appeared to regress an already-pinned cert
(217091901, band A, also nominally 280mm, previously "confirmed" at
U=1.70) — but that cert's build script never actually set a wall
thickness field, so its shared Elmhurst assessment had silently
inherited a stale 260mm from an earlier build. Fixed that build script
and rebuilt with the correct 280mm entry: Elmhurst's worksheet now also
gives U=1.40, matching 100031768368 and confirming the fix rather than
contradicting it.
Both certs move to (near-)exact lodged matches: 100031768368 59.12 ->
61.21 (lodged 61, within 0.5); 217091901 60.82 -> 61.59 (lodged 62,
exact). Corpus gauge 77.8% -> 78.6% within-0.5, MAE 0.636 -> 0.627 (14
corpus certs lodge exactly 280mm solid brick). TDD'd, 46 pins + full
suite green (2310 passed).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Top-floor flat, solid brick uninsulated, uninsulated flat roof, gas combi,
SINGLE glazing (glazed_type 5). Built in accredited Elmhurst RdSAP10 and every
heat-loss element matches the engine EXACTLY: walls 53.18, flat roof 145.57,
floor 0, party 0, and — with the faithful single glazing — windows 34.7114 W/K
(8.62 m2 x eff U 4.0268). Confirms the mapper's glazed_type 5 -> single (raw U
4.8) is spec-correct per epc_codes.csv, not the double it superficially
resembles. Engine 61 vs lodged 62; the -1.18 is a cost-side residual, not a
fabric bug. Pinned to the observed engine 61.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
