added landlord overrdies

docs/adr/0033-age-band-resolves-assumed-fabric-states.md

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+# Age band resolves the "(assumed)"/"as built"/"Unknown" fabric states
+
+ADR-0032 dec-4 **deferred** the `WallType` "(assumed) insulated" / "partial
+insulation (assumed)" states (and, transitively, flat roofs): their
+`wall_insulation_type` is "age-inferred in RdSAP, so the code is ambiguous and
+must be pinned against the Elmhurst accuracy harness rather than guessed." This
+ADR closes that deferral. The harness has now run. Terms in CONTEXT.md (Landlord
+Overrides, Effective EPC, Validation Cohort); supersedes ADR-0032 dec-4.
+
+## Status
+
+Accepted. Supersedes the deferral in ADR-0032 dec-4. Evidence:
+`scripts/hyde/uvalue_probe_{walls,roofs}.csv` (full A–M Elmhurst sweep, produced
+by `scripts/hyde/probe_uvalues.py`).
+
+## Context: what the Elmhurst sweep showed
+
+The SAP 10.2 spec defers RdSAP to "a separate document" (Appendix S, p.122), so
+the authoritative source for "what U-value does enum X at age Y produce" is the
+accredited Elmhurst RdSAP-10 entry tool itself. We drove it across all 13
+construction-age bands (A–M) for the two components Khalim flagged and read the
+tool's recomputed **Default U-value** for every option:
+
+* **Cavity wall, As Built** `[A–M]`:
+  `1.5, 1.5, 1.5, 1.5, 1.5, 1.0, 0.6, 0.6, 0.45, 0.35, 0.3, 0.28, 0.26`
+* **Cavity wall, Filled** `[A–M]`:
+  `0.7, 0.7, 0.7, 0.7, 0.7, 0.4, 0.35, 0.35, 0.45, 0.35, 0.3, 0.28, 0.26`
+* **Flat roof, As Built / Unknown** `[A–M]`:
+  `2.3, 2.3, 2.3, 2.3, 1.5, 0.68, 0.4, 0.35, 0.35, 0.25, 0.25, 0.18, 0.15`
+
+Two facts fall out:
+
+1. **Every value already lives in our tables.** As Built ≡ `(WALL_CAVITY, 0)`,
+   Filled ≡ `_CAVITY_FILLED_ENG`, flat As Built/Unknown ≡ `_FLAT_ROOF_BY_AGE`
+   (`domain/sap10_ml/rdsap_uvalues.py`) — exact match, all 13 bands. The U-value
+   layer was never the gap.
+2. **"Unknown" computes identically to "As Built"** at every band — confirming
+   Khalim's read that Unknown is handled like As Built.
+
+## Decisions
+
+### 1. The "(assumed)" qualifier is *not* a distinct insulation code — age band is
+
+ADR-0032 dec-4 worried that "partial insulation (assumed)" needs a
+`wall_insulation_type` code we couldn't name. The sweep shows why none exists:
+Elmhurst has **no "partial" enum**. "Partial insulation (assumed)" is simply
+*As Built (code 4) evaluated at band F (1976–1982)* → 1.0 W/m²K. Likewise
+"no insulation (assumed)" is As Built at an old band (A–E → 1.5) and "insulated
+(assumed)" is As Built at a newer band (G+ → ≤0.60). All three resolve to
+`wall_insulation_type = 4`; the **construction-age-band overlay** (already a
+separate, wired override component) supplies the U-value. This matches Khalim's
+bands: cavity ≤1975 uninsulated / 1976–82 partial / later insulated is exactly
+the As-Built-by-age curve above.
+
+### 2. Resolve to int codes, not a computed U-value override
+
+Because int codes + the existing age-band tables reproduce Elmhurst exactly,
+overlays keep emitting `wall_construction` / `wall_insulation_type` (walls) and
+`roof_construction` / `roof_insulation_thickness` (roofs) — no new
+`wall_u_value` / `roof_u_value` override path. This keeps the landlord overlay on
+the same code path as every Measure (ADR-0032 dec-1) and avoids a second way to
+move the wall/roof U-value. (Considered and rejected: writing a computed U-value
+override. It would duplicate the RdSAP tables already in the calculator and
+diverge the moment those tables are revised.)
+
+### 3. Walls — extend the state map; no new machinery
+
+`wall_type_overlay._STATE_INSULATION` gains the three "as built" variants
+("as built", "as built, insulated (assumed)", "as built, partial insulation
+(assumed)") → code 4, alongside the existing "no insulation (assumed)" → 4.
+These previously produced **no overlay** (silently dropping the landlord's
+correction). The age-band overlay does the rest.
+
+### 4. Flat roofs — the overlay must set `roof_construction_type`
+
+The calculator's flat-roof age-band path (`u_roof`, `_FLAT_ROOF_BY_AGE`) fires
+only when the roof is flat, which `heat_transmission.py` reads from the **string**
+`part.roof_construction_type` (`"flat" in roof_type_lower`, line 999) — *not* the
+int `roof_construction`. The roof overlay today sets only
+`roof_insulation_thickness`, so a flat-roof override can't reach that path. This
+ADR adds `roof_construction_type` to `BuildingPartOverlay` and has
+`roof_type_overlay` set it to `"Flat"` for the "Flat, …" family, alongside the
+existing `roof_insulation_thickness` (set when the description carries an explicit
+mm depth).
+
+The same shape-flag mechanism extends to pitched roofs with no clean depth:
+
+* `"Pitched, Unknown loft insulation"` → `roof_construction_type="Pitched"`,
+  thickness left `None` → the pitched age-band default (`_ROOF_BY_AGE`).
+* `"Pitched, no insulation*"` → `roof_construction_type="Pitched"` **plus**
+  `roof_insulation_thickness=0` → the uninsulated 2.30 (Table 16 row 0). Pitched
+  "no insulation" text is load-bearing in `u_roof` (§5.11 note) — it does NOT take
+  the age-band default, unlike flat. Setting `0` (not `None`) also lets this case
+  override a lodged numeric thickness, which the "Unknown" cases cannot.
+
+Constraint: the applicator only folds *non-None* overlay fields, so it cannot
+*clear* a lodged `roof_insulation_thickness` to `None`. For As Built / Unknown
+(no depth) the age-band default fires only when the baseline part carries no
+numeric thickness — true on the Hyde flow, where the landlord override IS the roof
+source and genuine As Built/Unknown lodgements carry `AB`/`ND`/None, not a number.
+A flat/pitched-Unknown override layered on a part that already has a numeric
+thickness keeps that thickness; that case is out of scope here and surfaced by the
+coverage audit (below) for the verify step.
+
+## Consequences
+
+* Previously-dropped Hyde rows now move the score: ~1,366 flat-roof overrides
+  (`Flat: As Built` + `Flat: Unknown`) and every cavity "as built/partial/
+  insulated (assumed)" wall. This is the point — a more accurate Effective EPC —
+  and (per ADR-0032 dec-5) such overlaid Properties stay excluded from the
+  Validation Cohort on the divergence signal.
+* `BuildingPartOverlay` gains a `roof_construction` field; `apply_simulations`
+  must fold it like `wall_construction`.
+* The decision is pinned by tests mirroring the probe CSVs (one row per
+  component × band), so a future RdSAP table revision that breaks parity trips a
+  regression rather than silently drifting from Elmhurst.
+* `scripts/hyde/probe_uvalues.py` stays as the re-runnable oracle: re-sweep to
+  re-confirm parity whenever the RdSAP tables or Elmhurst change.
+* A **coverage-audit pair** guards against the silent-no-op class this ADR fixes,
+  and is the reusable gate for every future portfolio (Hyde is the template):
+  - `scripts/hyde/audit_override_coverage.py` — enum-level: runs every override
+    value through its overlay mapper and flags those that produce no overlay or
+    only an inert field. Run it whenever an override enum or overlay changes.
+  - `scripts/hyde/audit_hyde_rows.py` — row-level: weights the verdict by actual
+    portfolio row counts and cross-checks that every "another/same dwelling above"
+    party-ceiling no-op is genuinely a Flat/Maisonette (a House/Bungalow with a
+    dwelling above is a data error, not a safe no-op — flagged to CSV for review).
+  Contradictory properties (party-ceiling roof on a non-flat type — Hyde had 50,
+  possibly houses split into flats) are **skipped entirely** by the `write` step:
+  no overrides are written for them and their org_refs are recorded to
+  `skipped_contradictory_properties.csv` for joint human review, rather than
+  guessing which of the two conflicting landlord fields is correct.
+  Known residue logged, not silently dropped: `PitchedWithSlopingCeiling: *`
+  (~272 Hyde rows, needs the col-3 path), `Roof room(s)` (needs `sap_room_in_roof`),
+  the `Renewables` column (no ComponentSpec — PV unmapped), and `Timber frame,
+  with additional insulation` (wall, ~7 rows).