diff --git a/src/viewport.cpp b/src/viewport.cpp
index 78dc2a0bf9..dce5424d20 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -1259,7 +1259,7 @@ static void ViewportAddWaypoints(DrawPixelInfo *dpi)
 
 void UpdateViewportSignPos(ViewportSign *sign, int left, int top, StringID str)
 {
-	char buffer[128];
+	char buffer[256];
 	uint w;
 
 	sign->top = top;
diff --git a/src/viewport_type.h b/src/viewport_type.h
index 98f56b8852..09bf2dcf3d 100644
--- a/src/viewport_type.h
+++ b/src/viewport_type.h
@@ -27,7 +27,7 @@ struct ViewPort {
 struct ViewportSign {
 	int32 left;
 	int32 top;
-	byte width_1, width_2;
+	uint16 width_1, width_2;
 };
 
 enum {