diff --git a/src/app/db/schema/property.ts b/src/app/db/schema/property.ts
index fdf01a18..309e3470 100644
--- a/src/app/db/schema/property.ts
+++ b/src/app/db/schema/property.ts
@@ -711,7 +711,7 @@ export const epcBuildingPart = pgTable(
     buildingPartNumber:     integer("building_part_number"),
     wallDryLined:           boolean("wall_dry_lined"),
     wallThicknessMm:        integer("wall_thickness_mm"),
-    wallInsulationThickness: text("wall_insulation_thickness"),
+    wallInsulationThickness: jsonb("wall_insulation_thickness"),
     // age band source
 
     // Floor