diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index a5ea618c..d8262869 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -1,5 +1,5 @@
 from datetime import date
-from typing import List, Sequence, Union
+from typing import List, Optional, Sequence, Union
 
 from datatypes.epc.domain.epc_property_data import (
     EnergyElement,
@@ -55,9 +55,11 @@ from datatypes.epc.surveys.pashub_rdsap_site_notes import (
     BuildingMeasurements,
     ExtensionConstruction,
     ExtensionMeasurements,
+    ExtensionRoofSpace,
     FloorMeasurement,
     HeatingAndHotWater,
     PasHubRdSapSiteNotes,
+    RoofSpaceDetail,
     Ventilation,
     Window,
 )
@@ -91,13 +93,15 @@ class EpcPropertyDataMapper:
         renewables = survey.renewables
         room_counts = survey.room_count_elements
 
-        sap_building_parts = [_map_main_building_part(construction, measurements)]
+        roof_space = survey.roof_space
+        sap_building_parts = [_map_main_building_part(construction, measurements, roof_space.main_building)]
         if construction.extensions and measurements.extensions:
             for ext_c in construction.extensions:
-                matching = [m for m in measurements.extensions if m.id == ext_c.id]
-                if matching:
+                matching_m = [m for m in measurements.extensions if m.id == ext_c.id]
+                matching_r = [r for r in (roof_space.extensions or []) if r.id == ext_c.id]
+                if matching_m:
                     sap_building_parts.append(
-                        _map_extension_building_part(ext_c, matching[0])
+                        _map_extension_building_part(ext_c, matching_m[0], matching_r[0] if matching_r else None)
                     )
 
         total_floor_area = round(
@@ -1428,11 +1432,20 @@ def _map_floor_dimensions(floors: List[FloorMeasurement]) -> List[SapFloorDimens
     ]
 
 
+def _map_roof(roof: Optional[Union[RoofSpaceDetail, ExtensionRoofSpace]]) -> tuple[Optional[str], Optional[Union[str, int]]]:
+    if roof is None:
+        return None, None
+    thickness: Optional[Union[str, int]] = roof.insulation_thickness_mm if roof.insulation_thickness_mm is not None else roof.insulation_thickness
+    return roof.insulation_at or None, thickness
+
+
 def _map_main_building_part(
     construction: BuildingConstruction,
     measurements: BuildingMeasurements,
+    roof: RoofSpaceDetail,
 ) -> SapBuildingPart:
     main = construction.main_building
+    roof_location, roof_thickness = _map_roof(roof)
     return SapBuildingPart(
         identifier="main",
         construction_age_band=_extract_age_band(main.age_range),
@@ -1442,13 +1455,17 @@ def _map_main_building_part(
         party_wall_construction=main.party_wall_construction_type,
         sap_floor_dimensions=_map_floor_dimensions(measurements.main_building.floors),
         wall_thickness_mm=main.wall_thickness_mm,
+        roof_insulation_location=roof_location,
+        roof_insulation_thickness=roof_thickness,
     )
 
 
 def _map_extension_building_part(
     ext_c: ExtensionConstruction,
     ext_m: ExtensionMeasurements,
+    roof: Optional[ExtensionRoofSpace],
 ) -> SapBuildingPart:
+    roof_location, roof_thickness = _map_roof(roof)
     return SapBuildingPart(
         identifier=f"extension_{ext_c.id}",
         construction_age_band=_extract_age_band(ext_c.age_range),
@@ -1458,6 +1475,8 @@ def _map_extension_building_part(
         party_wall_construction=ext_c.party_wall_construction_type,
         sap_floor_dimensions=_map_floor_dimensions(ext_m.floors),
         wall_thickness_mm=ext_c.wall_thickness_mm,
+        roof_insulation_location=roof_location,
+        roof_insulation_thickness=roof_thickness,
     )