Extract the PasHub detailed room-in-roof block 🟩

_parse_room_in_roof captures the RdSAP §3.10 block (age range, floor area,
gables with Exposed/Party type, slopes, common walls, flat ceiling as
length x height) on main and extension roof spaces; both part builders now
carry it to sap_room_in_roof (issue #1590 bug 5 — closes the last #1590
subtask). Harness MAE 1.748 (754917 corrects to pashub's own pre-SAP; RIR
surfaces now billed per-surface instead of as insulated loft).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/documents_parser/extractor.py

@@ -19,6 +19,8 @@ from datatypes.epc.surveys.pashub_rdsap_site_notes import (
     MainHeating,
     PasHubRdSapSiteNotes,
     PvArrayDetail,
+    RoomInRoofDetail,
+    RoomInRoofSurfaceDetail,
     Renewables,
     RoomCountElements,
     RoofSpace,
@@ -672,6 +674,49 @@ class PasHubRdSapSiteNotesExtractor:
         except (ValueError, IndexError):
             return None, val
 
+    def _parse_rir_surface(
+        self, data: List[str], prefix: str, with_type: bool = False
+    ) -> Optional[RoomInRoofSurfaceDetail]:
+        """One room-in-roof surface's "{prefix} length/height[/type]" lines
+        ("6.64 m" → 6.64). None when the surface isn't lodged."""
+        length = self._get_in(data, f"{prefix} length:")
+        height = self._get_in(data, f"{prefix} height:")
+        if length is None and height is None:
+            return None
+        return RoomInRoofSurfaceDetail(
+            length_m=float(length.split()[0]) if length else None,
+            height_m=float(height.split()[0]) if height else None,
+            gable_type=self._get_in(data, f"{prefix} type:") if with_type else None,
+        )
+
+    def _parse_room_in_roof(self, data: List[str]) -> Optional[RoomInRoofDetail]:
+        """The RdSAP §3.10 detailed room-in-roof block lodged under "Are there
+        rooms in the roof? Yes" — dropped detail bills ~the whole RIR shell as
+        well-insulated loft (issue #1590 bug 5)."""
+        if not self._bool_in(data, "Are there rooms in the roof?"):
+            return None
+        area_raw = self._get_in(data, "Floor area of room in roof:")
+
+        def surfaces(
+            prefix: str, with_type: bool = False
+        ) -> Optional[List[RoomInRoofSurfaceDetail]]:
+            out = [
+                s
+                for n in (1, 2)
+                if (s := self._parse_rir_surface(data, f"{prefix} {n}", with_type))
+                is not None
+            ]
+            return out or None
+
+        return RoomInRoofDetail(
+            age_range=self._get_in(data, "Roof room age range:"),
+            floor_area_m2=float(area_raw.split()[0]) if area_raw else None,
+            gables=surfaces("Gable wall", with_type=True),
+            slopes=surfaces("Slope"),
+            common_walls=surfaces("Common wall"),
+            flat_ceilings=surfaces("Flat ceiling"),
+        )
+
     def _parse_roof_space_detail(self, data: List[str]) -> RoofSpaceDetail:
         thickness_mm, thickness_str = self._parse_insulation_thickness(
             self._get_in(data, "Roofs - Insulation Thickness:")
@@ -687,6 +732,7 @@ class PasHubRdSapSiteNotesExtractor:
             rooms_in_roof=self._bool_in(data, "Are there rooms in the roof?"),
             insulation_thickness_mm=thickness_mm,
             insulation_thickness=thickness_str,
+            room_in_roof=self._parse_room_in_roof(data),
         )
 
     def _parse_extension_roof_space(
@@ -707,6 +753,7 @@ class PasHubRdSapSiteNotesExtractor:
             rooms_in_roof=self._bool_in(data, "Are there rooms in the roof?"),
             insulation_thickness_mm=thickness_mm,
             insulation_thickness=thickness_str,
+            room_in_roof=self._parse_room_in_roof(data),
         )
 
     def _parse_floor_measurements(self, data: List[str]) -> List[FloorMeasurement]:

datatypes/epc/domain/mapper.py

@@ -6085,6 +6085,7 @@ def _map_extension_building_part(
     roof_location, roof_thickness = _map_roof(roof)
     return SapBuildingPart(
         identifier=BuildingPartIdentifier.extension(ext_c.id),
+        sap_room_in_roof=_pashub_room_in_roof(roof) if roof is not None else None,
         construction_age_band=_extract_age_band(ext_c.age_range),
         # PasHub surveys never lodge a basement wall; pin the flag so a
         # "System Build" wall (code 6, which doubles as the gov-API basement