diff --git a/src/resizer/room.js b/src/resizer/room.js
index 94c8a11484..51bd0d82d8 100644
--- a/src/resizer/room.js
+++ b/src/resizer/room.js
@@ -65,8 +65,9 @@ class RoomDistributor {
 
     _contentSize(item) {
         const scrollItem = item.domNode.querySelector(".mx_RoomSubList_scroll");
-        const headerHeight = item.size() - scrollItem.offsetHeight;
-        return headerHeight + scrollItem.scrollHeight + 4;
+        const header = item.domNode.querySelector(".mx_RoomSubList_labelContainer");
+        const headerHeight = item.sizer.getItemSize(header);
+        return headerHeight + scrollItem.scrollHeight;
     }
 
     resize(size) {