diff --git a/src/newgrf_commons.cpp b/src/newgrf_commons.cpp
index d0d1c1c5f8..59118a6ffe 100644
--- a/src/newgrf_commons.cpp
+++ b/src/newgrf_commons.cpp
@@ -141,6 +141,16 @@ uint16 OverrideManagerBase::AddEntityID(byte grf_local_id, uint32 grfid, byte su
 	return invalid_ID;
 }
 
+/**
+ * Gives the GRFID of the file the entity belongs to.
+ * @param entity_id ID of the entity being queried.
+ * @return GRFID.
+ */
+uint16 OverrideManagerBase::GetGRFID(uint16 entity_id) const
+{
+	return mapping_ID[entity_id].grfid;
+}
+
 /**
  * Gives the substitute of the entity, as specified by the grf file
  * @param entity_id of the entity being queried
diff --git a/src/newgrf_commons.h b/src/newgrf_commons.h
index d0e556fafb..e38111371c 100644
--- a/src/newgrf_commons.h
+++ b/src/newgrf_commons.h
@@ -185,6 +185,7 @@ public:
 	void Add(uint8 local_id, uint32 grfid, uint entity_type);
 	virtual uint16 AddEntityID(byte grf_local_id, uint32 grfid, byte substitute_id);
 
+	uint16 GetGRFID(uint16 entity_id) const;
 	uint16 GetSubstituteID(uint16 entity_id) const;
 	virtual uint16 GetID(uint8 grf_local_id, uint32 grfid) const;
 
diff --git a/src/newgrf_house.cpp b/src/newgrf_house.cpp
index 52eb7b286e..fd0281e4ea 100644
--- a/src/newgrf_house.cpp
+++ b/src/newgrf_house.cpp
@@ -344,7 +344,7 @@ static uint32 HouseGetVariable(const ResolverObject *object, byte variable, byte
 			if (house_id < NEW_HOUSE_OFFSET) return 0;
 			/* Checking the grffile information via HouseSpec doesn't work
 			 * in case the newgrf was removed. */
-			return _house_mngr.mapping_ID[house_id].grfid;
+			return _house_mngr.GetGRFID(house_id);
 		}
 	}