diff --git a/backend/magic_plan/audit_script.py b/backend/magic_plan/audit_script.py
index 2eccdb27..deea7b8d 100644
--- a/backend/magic_plan/audit_script.py
+++ b/backend/magic_plan/audit_script.py
@@ -17,7 +17,11 @@ _BOLD = Font(bold=True)
 _TOTAL_COLS = 25  # A–Y
 _BLANK_SEPARATOR_COLS = {5, 21}
 _MEDIUM_RIGHT = Border(right=Side(style="medium"))
+_MEDIUM_LEFT = Border(left=Side(style="medium"))
+_MEDIUM_BOTTOM = Side(style="medium")
 _SECTION_BOUNDARY_COLS = {4, 11, 15, 20}
+_SECTION_START_COLS = {6, 22}
+_FLOOR_MERGE_SEGMENTS = [(1, 4), (6, 20), (22, 25)]
 
 
 @dataclass
@@ -35,6 +39,7 @@ class AuditRow:
     window_opening_type: Optional[str] = None
     door_location: Optional[str] = None
     door_width_mm: Optional[float] = None
+    is_last_room_row: bool = False
     opening_count: Optional[int] = None
     opening_width_m: Optional[float] = None
     opening_height_m: Optional[float] = None
@@ -80,6 +85,9 @@ def _build_rows(plan: Plan) -> list[AuditRow]:
                     row.door_location = room.name
                     row.door_width_mm = door.width_mm
 
+                if i == n_rows - 1:
+                    row.is_last_room_row = True
+
                 rows.append(row)
 
     return rows
@@ -88,6 +96,19 @@ def _build_rows(plan: Plan) -> list[AuditRow]:
 def _apply_section_borders(ws: Worksheet, row: int) -> None:
     for col in _SECTION_BOUNDARY_COLS:
         ws.cell(row=row, column=col).border = _MEDIUM_RIGHT
+    for col in _SECTION_START_COLS:
+        ws.cell(row=row, column=col).border = _MEDIUM_LEFT
+
+
+def _apply_room_bottom_border(ws: Worksheet, row: int) -> None:
+    medium = Side(style="medium")
+    for col in range(1, _TOTAL_COLS + 1):
+        if col in _SECTION_BOUNDARY_COLS:
+            ws.cell(row=row, column=col).border = Border(right=medium, bottom=medium)
+        elif col in _SECTION_START_COLS:
+            ws.cell(row=row, column=col).border = Border(left=medium, bottom=medium)
+        else:
+            ws.cell(row=row, column=col).border = Border(bottom=medium)
 
 
 def _write_headers(ws: Worksheet) -> None:
@@ -137,15 +158,13 @@ def _write_data_rows(ws: Worksheet, rows: list[AuditRow]) -> None:
     xl_row = 3
     for row in rows:
         if row.floor_level is not None:
-            cell = ws.cell(row=xl_row, column=1, value=f"Floor {row.floor_level}")
-            cell.font = _BOLD
-            cell.fill = _FLOOR_FILL
-            ws.merge_cells(
-                start_row=xl_row,
-                start_column=1,
-                end_row=xl_row,
-                end_column=_TOTAL_COLS,
-            )
+            for idx, (c1, c2) in enumerate(_FLOOR_MERGE_SEGMENTS):
+                ws.merge_cells(start_row=xl_row, start_column=c1, end_row=xl_row, end_column=c2)
+                label = f"Floor {row.floor_level}" if idx == 0 else None
+                cell = ws.cell(row=xl_row, column=c1, value=label)
+                cell.fill = _FLOOR_FILL
+                if idx == 0:
+                    cell.font = _BOLD
         else:
             ws.cell(row=xl_row, column=1, value=row.room_name)
             ws.cell(row=xl_row, column=2, value=row.room_width_m)
@@ -159,7 +178,9 @@ def _write_data_rows(ws: Worksheet, rows: list[AuditRow]) -> None:
             ws.cell(row=xl_row, column=11, value=row.window_opening_type)
             ws.cell(row=xl_row, column=22, value=row.door_location)
             ws.cell(row=xl_row, column=23, value=row.door_width_mm)
-        _apply_section_borders(ws, xl_row)
+            _apply_section_borders(ws, xl_row)
+            if row.is_last_room_row:
+                _apply_room_bottom_border(ws, xl_row)
         xl_row += 1
 
 
diff --git a/backend/magic_plan/tests/test_audit_script.py b/backend/magic_plan/tests/test_audit_script.py
index fea487a5..e56b6977 100644
--- a/backend/magic_plan/tests/test_audit_script.py
+++ b/backend/magic_plan/tests/test_audit_script.py
@@ -273,9 +273,10 @@ def test_apply_section_borders_sets_medium_right_border_on_boundary_columns() ->
     # Assert — medium right-border on last col of each subtable
     for col in (4, 11, 15, 20):
         assert ws.cell(row=1, column=col).border.right.style == "medium", f"col {col}"
-    # Assert — non-boundary columns are untouched
+    # Assert — non-boundary columns have no medium right-border
     for col in (1, 6, 12, 22):
-        assert ws.cell(row=1, column=col).border.right.style is None, f"col {col}"
+        right = ws.cell(row=1, column=col).border.right
+        assert right is None or right.style != "medium", f"col {col}"
 
 
 def test_write_data_rows_places_door_data_at_cols_22_to_25() -> None: