diff --git a/src/newgrf_house.cpp b/src/newgrf_house.cpp
--- a/src/newgrf_house.cpp
+++ b/src/newgrf_house.cpp
@@ -22,6 +22,7 @@
 #include "functions.h"
 #include "player_func.h"
 #include "animated_tile_func.h"
+#include "date_func.h"
 
 #include "table/strings.h"
 #include "table/sprites.h"