diff --git a/backend/documents_parser/extractor.py b/backend/documents_parser/extractor.py
index 334cf08cc..767e8c731 100644
--- a/backend/documents_parser/extractor.py
+++ b/backend/documents_parser/extractor.py
@@ -685,10 +685,19 @@ class PasHubRdSapSiteNotesExtractor:
         height = self._get_in(data, f"{prefix} height:")
         if length is None and height is None:
             return None
+        # "{prefix}: Are you able to provide details of the insulation …?" —
+        # the question wraps onto a second PDF line, so the Yes/No sits at
+        # offset 2 from the stable first-line key. Absent on legacy forms.
+        known_raw = self._get_in(
+            data, f"{prefix}: Are you able to provide details of the", offset=2
+        )
         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,
+            insulation_known=(
+                None if known_raw is None else known_raw.lower() == "yes"
+            ),
         )
 
     def _parse_room_in_roof(self, data: List[str]) -> Optional[RoomInRoofDetail]: