diff --git a/src/hooks/roofcover/useRoofAllocationSetting.js b/src/hooks/roofcover/useRoofAllocationSetting.js
index a8caf5ce..6d573ff0 100644
--- a/src/hooks/roofcover/useRoofAllocationSetting.js
+++ b/src/hooks/roofcover/useRoofAllocationSetting.js
@@ -273,7 +273,7 @@ export function useRoofAllocationSetting(id) {
     const roofs = canvas.getObjects().filter((obj) => obj.name === POLYGON_TYPE.ROOF)
 
     for (let i = 0; i < roofs.length; i++) {
-      if (roofs[i].roofMaterial.index === idx) {
+      if (roofs[i].roofMaterial?.index === idx) {
         swalFire({ type: 'alert', icon: 'error', text: getMessage('roof.material.can.not.delete') })
         return
       }