diff --git a/domain/modelling/scoring/overlay_applicator.py b/domain/modelling/scoring/overlay_applicator.py
index 9c83724a..961f4e02 100644
--- a/domain/modelling/scoring/overlay_applicator.py
+++ b/domain/modelling/scoring/overlay_applicator.py
@@ -19,6 +19,7 @@ from datatypes.epc.domain.epc_property_data import (
 )
 from domain.modelling.simulation import (
     EpcSimulation,
+    GlazingOverlay,
     HeatingOverlay,
     LightingOverlay,
     SecondaryHeatingOverlay,
@@ -53,6 +54,8 @@ def apply_simulations(
             )
         if simulation.lighting is not None:
             _fold_lighting(result, simulation.lighting)
+        if simulation.glazing is not None:
+            _fold_glazing(result, simulation.glazing)
         if simulation.heating is not None:
             _fold_heating(result, simulation.heating)
         if simulation.secondary_heating is not None:
@@ -202,6 +205,21 @@ def _fold_window(window: SapWindow, overlay: WindowOverlay) -> None:
         details.solar_transmittance = overlay.solar_transmittance
 
 
+def _fold_glazing(epc: EpcPropertyData, overlay: GlazingOverlay) -> None:
+    """Expand a whole-dwelling `GlazingOverlay` across every window: set each
+    window's `glazing_type` to the corrected SAP10 code AND clear its lodged
+    transmission U, so `heat_transmission`'s Table-24 cascade re-derives U from
+    the new type (the lodged U was for the old, mis-recorded glazing). A landlord
+    glazing override carries no per-window geometry, so it applies uniformly —
+    the expansion lives here because the baseline window list is known only at
+    fold time."""
+    if overlay.glazing_type is None:
+        return
+    for window in epc.sap_windows:
+        window.glazing_type = overlay.glazing_type
+        window.window_transmission_details = None
+
+
 def _fold_ventilation(
     baseline: Optional[SapVentilation], overlay: VentilationOverlay
 ) -> SapVentilation: