diff --git a/app/src/frontend/building/data-containers/age.tsx b/app/src/frontend/building/data-containers/age.tsx
index 914f059b..fb50f751 100644
--- a/app/src/frontend/building/data-containers/age.tsx
+++ b/app/src/frontend/building/data-containers/age.tsx
@@ -18,7 +18,7 @@ const AgeView: React.FunctionComponent<CategoryViewProps> = (props) => {
     const currentYear = new Date().getFullYear();
     if (props.building.date_source == "Expert knowledge of building" ||
         props.building.date_source == "Expert estimate from image" ||
-        props.building.date_source == ""
+        props.building.date_source == null
        ){
       return (
           <Fragment>