diff --git a/src/newgrf_house.cpp b/src/newgrf_house.cpp
--- a/src/newgrf_house.cpp
+++ b/src/newgrf_house.cpp
@@ -39,7 +39,7 @@ HouseOverrideManager _house_mngr(NEW_HOU
  * @param initial_random_bits Random bits during construction checks.
  * @param watched_cargo_triggers Cargo types that triggered the watched cargo callback.
  */
-HouseScopeResolver::HouseScopeResolver(ResolverObject *ro, HouseID house_id, TileIndex tile, Town *town,
+HouseScopeResolver::HouseScopeResolver(ResolverObject &ro, HouseID house_id, TileIndex tile, Town *town,
 			bool not_yet_constructed, uint8 initial_random_bits, uint32 watched_cargo_triggers)
 		: ScopeResolver(ro)
 {
@@ -78,8 +78,8 @@ HouseResolverObject::HouseResolverObject
 		CallbackID callback, uint32 param1, uint32 param2,
 		bool not_yet_constructed, uint8 initial_random_bits, uint32 watched_cargo_triggers)
 	: ResolverObject(GetHouseSpecGrf(house_id), callback, param1, param2),
-	house_scope(this, house_id, tile, town, not_yet_constructed, initial_random_bits, watched_cargo_triggers),
-	town_scope(this, town, not_yet_constructed) // Don't access StorePSA if house is not yet constructed.
+	house_scope(*this, house_id, tile, town, not_yet_constructed, initial_random_bits, watched_cargo_triggers),
+	town_scope(*this, town, not_yet_constructed) // Don't access StorePSA if house is not yet constructed.
 {
 }
 
@@ -352,7 +352,7 @@ static uint32 GetDistanceFromNearbyHouse
 		}
 
 		/* Land info for nearby tiles. */
-		case 0x62: return GetNearbyTileInformation(parameter, this->tile, this->ro->grffile->grf_version >= 8);
+		case 0x62: return GetNearbyTileInformation(parameter, this->tile, this->ro.grffile->grf_version >= 8);
 
 		/* Current animation frame of nearby house tiles */
 		case 0x63: {
@@ -362,7 +362,7 @@ static uint32 GetDistanceFromNearbyHouse
 
 		/* Cargo acceptance history of nearby stations */
 		case 0x64: {
-			CargoID cid = GetCargoTranslation(parameter, this->ro->grffile);
+			CargoID cid = GetCargoTranslation(parameter, this->ro.grffile);
 			if (cid == CT_INVALID) return 0;
 
 			/* Extract tile offset. */
@@ -400,7 +400,7 @@ static uint32 GetDistanceFromNearbyHouse
 			/* Information about the grf local classid if the house has a class */
 			uint houseclass = 0;
 			if (hs->class_id != HOUSE_NO_CLASS) {
-				houseclass = (hs->grf_prop.grffile == this->ro->grffile ? 1 : 2) << 8;
+				houseclass = (hs->grf_prop.grffile == this->ro.grffile ? 1 : 2) << 8;
 				houseclass |= _class_mapping[hs->class_id].class_id;
 			}
 			/* old house type or grf-local houseid */
@@ -408,7 +408,7 @@ static uint32 GetDistanceFromNearbyHouse
 			if (this->house_id < NEW_HOUSE_OFFSET) {
 				local_houseid = this->house_id;
 			} else {
-				local_houseid = (hs->grf_prop.grffile == this->ro->grffile ? 1 : 2) << 8;
+				local_houseid = (hs->grf_prop.grffile == this->ro.grffile ? 1 : 2) << 8;
 				local_houseid |= hs->grf_prop.local_id;
 			}
 			return houseclass << 16 | local_houseid;
@@ -440,7 +440,7 @@ uint16 GetHouseCallback(CallbackID callb
 	HouseResolverObject object(house_id, tile, town, callback, param1, param2,
 			not_yet_constructed, initial_random_bits, watched_cargo_triggers);
 
-	const SpriteGroup *group = SpriteGroup::Resolve(HouseSpec::Get(house_id)->grf_prop.spritegroup[0], &object);
+	const SpriteGroup *group = SpriteGroup::Resolve(HouseSpec::Get(house_id)->grf_prop.spritegroup[0], object);
 	if (group == NULL) return CALLBACK_FAILED;
 
 	return group->GetCallbackResult();
@@ -490,7 +490,7 @@ void DrawNewHouseTile(TileInfo *ti, Hous
 
 	HouseResolverObject object(house_id, ti->tile, Town::GetByTile(ti->tile));
 
-	const SpriteGroup *group = SpriteGroup::Resolve(hs->grf_prop.spritegroup[0], &object);
+	const SpriteGroup *group = SpriteGroup::Resolve(hs->grf_prop.spritegroup[0], object);
 	if (group != NULL && group->type == SGT_TILELAYOUT) {
 		/* Limit the building stage to the number of stages supplied. */
 		const TileLayoutSpriteGroup *tlgroup = (const TileLayoutSpriteGroup *)group;
@@ -615,7 +615,7 @@ static void DoTriggerHouse(TileIndex til
 	HouseResolverObject object(hid, tile, Town::GetByTile(tile), CBID_RANDOM_TRIGGER);
 	object.trigger = trigger;
 
-	const SpriteGroup *group = SpriteGroup::Resolve(hs->grf_prop.spritegroup[0], &object);
+	const SpriteGroup *group = SpriteGroup::Resolve(hs->grf_prop.spritegroup[0], object);
 	if (group == NULL) return;
 
 	byte new_random_bits = Random();