diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index ee440aa464..4ec1f05dc3 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -945,40 +945,40 @@ void FinaliseCargoArray()
  * @param filename The filename of the newgrf this house was defined in.
  * @return Whether the given housespec is valid.
  */
-static bool IsHouseSpecValid(HouseSpec *hs, const HouseSpec *next1, const HouseSpec *next2, const HouseSpec *next3, const std::string &filename)
+static bool IsHouseSpecValid(HouseSpec &hs, const HouseSpec *next1, const HouseSpec *next2, const HouseSpec *next3, const std::string &filename)
 {
-	if ((hs->building_flags.Any(BUILDING_HAS_2_TILES) &&
+	if ((hs.building_flags.Any(BUILDING_HAS_2_TILES) &&
 				(next1 == nullptr || !next1->enabled || next1->building_flags.Any(BUILDING_HAS_1_TILE))) ||
-			(hs->building_flags.Any(BUILDING_HAS_4_TILES) &&
+			(hs.building_flags.Any(BUILDING_HAS_4_TILES) &&
 				(next2 == nullptr || !next2->enabled || next2->building_flags.Any(BUILDING_HAS_1_TILE) ||
 				next3 == nullptr || !next3->enabled || next3->building_flags.Any(BUILDING_HAS_1_TILE)))) {
-		hs->enabled = false;
-		if (!filename.empty()) Debug(grf, 1, "FinaliseHouseArray: {} defines house {} as multitile, but no suitable tiles follow. Disabling house.", filename, hs->grf_prop.local_id);
+		hs.enabled = false;
+		if (!filename.empty()) Debug(grf, 1, "FinaliseHouseArray: {} defines house {} as multitile, but no suitable tiles follow. Disabling house.", filename, hs.grf_prop.local_id);
 		return false;
 	}
 
 	/* Some places sum population by only counting north tiles. Other places use all tiles causing desyncs.
 	 * As the newgrf specs define population to be zero for non-north tiles, we just disable the offending house.
 	 * If you want to allow non-zero populations somewhen, make sure to sum the population of all tiles in all places. */
-	if ((hs->building_flags.Any(BUILDING_HAS_2_TILES) && next1->population != 0) ||
-			(hs->building_flags.Any(BUILDING_HAS_4_TILES) && (next2->population != 0 || next3->population != 0))) {
-		hs->enabled = false;
-		if (!filename.empty()) Debug(grf, 1, "FinaliseHouseArray: {} defines multitile house {} with non-zero population on additional tiles. Disabling house.", filename, hs->grf_prop.local_id);
+	if ((hs.building_flags.Any(BUILDING_HAS_2_TILES) && next1->population != 0) ||
+			(hs.building_flags.Any(BUILDING_HAS_4_TILES) && (next2->population != 0 || next3->population != 0))) {
+		hs.enabled = false;
+		if (!filename.empty()) Debug(grf, 1, "FinaliseHouseArray: {} defines multitile house {} with non-zero population on additional tiles. Disabling house.", filename, hs.grf_prop.local_id);
 		return false;
 	}
 
 	/* Substitute type is also used for override, and having an override with a different size causes crashes.
 	 * This check should only be done for NewGRF houses because grf_prop.subst_id is not set for original houses.*/
-	if (!filename.empty() && (hs->building_flags & BUILDING_HAS_1_TILE) != (HouseSpec::Get(hs->grf_prop.subst_id)->building_flags & BUILDING_HAS_1_TILE)) {
-		hs->enabled = false;
-		Debug(grf, 1, "FinaliseHouseArray: {} defines house {} with different house size then it's substitute type. Disabling house.", filename, hs->grf_prop.local_id);
+	if (!filename.empty() && (hs.building_flags & BUILDING_HAS_1_TILE) != (HouseSpec::Get(hs.grf_prop.subst_id)->building_flags & BUILDING_HAS_1_TILE)) {
+		hs.enabled = false;
+		Debug(grf, 1, "FinaliseHouseArray: {} defines house {} with different house size then it's substitute type. Disabling house.", filename, hs.grf_prop.local_id);
 		return false;
 	}
 
 	/* Make sure that additional parts of multitile houses are not available. */
-	if (!hs->building_flags.Any(BUILDING_HAS_1_TILE) && (hs->building_availability & HZ_ZONALL) != 0 && (hs->building_availability & HZ_CLIMALL) != 0) {
-		hs->enabled = false;
-		if (!filename.empty()) Debug(grf, 1, "FinaliseHouseArray: {} defines house {} without a size but marked it as available. Disabling house.", filename, hs->grf_prop.local_id);
+	if (!hs.building_flags.Any(BUILDING_HAS_1_TILE) && (hs.building_availability & HZ_ZONALL) != 0 && (hs.building_availability & HZ_CLIMALL) != 0) {
+		hs.enabled = false;
+		if (!filename.empty()) Debug(grf, 1, "FinaliseHouseArray: {} defines house {} without a size but marked it as available. Disabling house.", filename, hs.grf_prop.local_id);
 		return false;
 	}
 
@@ -1040,7 +1040,7 @@ static void FinaliseHouseArray()
 			const HouseSpec *next2 = (i + 2 < num_houses ? file.housespec[i + 2].get() : nullptr);
 			const HouseSpec *next3 = (i + 3 < num_houses ? file.housespec[i + 3].get() : nullptr);
 
-			if (!IsHouseSpecValid(hs, next1, next2, next3, file.filename)) continue;
+			if (!IsHouseSpecValid(*hs, next1, next2, next3, file.filename)) continue;
 
 			_house_mngr.SetEntitySpec(hs);
 		}
@@ -1054,7 +1054,7 @@ static void FinaliseHouseArray()
 
 		/* We need to check all houses again to we are sure that multitile houses
 		 * did get consecutive IDs and none of the parts are missing. */
-		if (!IsHouseSpecValid(hs, next1, next2, next3, std::string{})) {
+		if (!IsHouseSpecValid(*hs, next1, next2, next3, std::string{})) {
 			/* GetHouseNorthPart checks 3 houses that are directly before
 			 * it in the house pool. If any of those houses have multi-tile
 			 * flags set it assumes it's part of a multitile house. Since