diff --git a/src/hooks/roofcover/useAuxiliaryDrawing.js b/src/hooks/roofcover/useAuxiliaryDrawing.js
index c854ae77..7b8c2596 100644
--- a/src/hooks/roofcover/useAuxiliaryDrawing.js
+++ b/src/hooks/roofcover/useAuxiliaryDrawing.js
@@ -887,7 +887,7 @@ export function useAuxiliaryDrawing(id, isUseEffect = true) {
           line.attributes = {
             ...line.attributes,
             roofId: roofBase.id,
-            actualSize: line.attributes?.actualSize ?? 0,
+            actualSize: line.attributes?.actualSize ?? line.getLength(),
             planeSize: line.getLength(),
           }
           line.isAuxiliaryFixed = true