Index: src/newgrf.cpp
===================================================================
--- src/newgrf.cpp	(revision 19055)
+++ src/newgrf.cpp	(working copy)
@@ -2325,6 +2325,8 @@
 									grfmsg(2, "IndustriesChangeInfo: Attempt to use industry tile %u with industry id %u, not yet defined. Ignoring.", local_tile_id, indid);
 								} else {
 									/* Declared as been valid, can be used */
+									itt[k].ti.x = (int8)GB(itt[k].ti.x, 0, 8);
+									itt[k].ti.y = (int8)GB(itt[k].ti.y, 0, 8);
 									itt[k].gfx = tempid;
 									size = k + 1;
 									copy_from = itt;
Index: src/industrytype.h
===================================================================
--- src/industrytype.h	(revision 19055)
+++ src/industrytype.h	(working copy)
@@ -84,6 +84,7 @@
 enum IndustryTileSpecialFlags {
 	INDTILE_SPECIAL_NONE                  = 0,
 	INDTILE_SPECIAL_NEXTFRAME_RANDOMBITS  = 1 << 0, ///< Callback 0x26 needs random bits
+	INDTILE_SPECIAL_DONT_BUILD            = 1 << 1, ///< Tile is not actually built (intended for checking clearance on layouts)
 };
 DECLARE_ENUM_AS_BIT_SET(IndustryTileSpecialFlags);
 
Index: src/industry_cmd.cpp
===================================================================
--- src/industry_cmd.cpp	(revision 19055)
+++ src/industry_cmd.cpp	(working copy)
@@ -1288,43 +1288,47 @@
 				return false;
 			}
 		} else {
-			if (!EnsureNoVehicleOnGround(cur_tile)) return false;
-			if (MayHaveBridgeAbove(cur_tile) && IsBridgeAbove(cur_tile)) return false;
+			const IndustryTileSpec *its = GetIndustryTileSpec(gfx);		
+			if (!(its->special_flags & INDTILE_SPECIAL_DONT_BUILD) && ((it->ti.x < 0) || (it->ti.y < 0))) {
+				return false;  // The newgrf author has specified negative offset without setting prop 12 bit 1.  Wrong.
+			} else {
+				
+				if (!EnsureNoVehicleOnGround(cur_tile)) return false;
+				if (MayHaveBridgeAbove(cur_tile) && IsBridgeAbove(cur_tile)) return false;
 
-			const IndustryTileSpec *its = GetIndustryTileSpec(gfx);
+				IndustryBehaviour ind_behav = GetIndustrySpec(type)->behaviour;
 
-			IndustryBehaviour ind_behav = GetIndustrySpec(type)->behaviour;
+				/* Perform land/water check if not disabled */
+				if (!HasBit(its->slopes_refused, 5) && (IsWaterTile(cur_tile) == !(ind_behav & INDUSTRYBEH_BUILT_ONWATER))) return false;
 
-			/* Perform land/water check if not disabled */
-			if (!HasBit(its->slopes_refused, 5) && (IsWaterTile(cur_tile) == !(ind_behav & INDUSTRYBEH_BUILT_ONWATER))) return false;
+				if (HasBit(its->callback_mask, CBM_INDT_SHAPE_CHECK)) {
+					custom_shape = true;
+					if (!PerformIndustryTileSlopeCheck(tile, cur_tile, its, type, gfx, itspec_index)) return false;
+				} else {
+					Slope tileh = GetTileSlope(cur_tile, NULL);
+					refused_slope |= IsSlopeRefused(tileh, its->slopes_refused);
+				}
 
-			if (HasBit(its->callback_mask, CBM_INDT_SHAPE_CHECK)) {
-				custom_shape = true;
-				if (!PerformIndustryTileSlopeCheck(tile, cur_tile, its, type, gfx, itspec_index)) return false;
-			} else {
-				Slope tileh = GetTileSlope(cur_tile, NULL);
-				refused_slope |= IsSlopeRefused(tileh, its->slopes_refused);
-			}
+				if ((ind_behav & (INDUSTRYBEH_ONLY_INTOWN | INDUSTRYBEH_TOWN1200_MORE)) || // Tile must be a house
+						((ind_behav & INDUSTRYBEH_ONLY_NEARTOWN) && IsTileType(cur_tile, MP_HOUSE))) { // Tile is allowed to be a house (and it is a house)
+					if (!IsTileType(cur_tile, MP_HOUSE)) {
+						_error_message = STR_ERROR_CAN_ONLY_BE_BUILT_IN_TOWNS;
+						return false;
+					}
 
-			if ((ind_behav & (INDUSTRYBEH_ONLY_INTOWN | INDUSTRYBEH_TOWN1200_MORE)) || // Tile must be a house
-					((ind_behav & INDUSTRYBEH_ONLY_NEARTOWN) && IsTileType(cur_tile, MP_HOUSE))) { // Tile is allowed to be a house (and it is a house)
-				if (!IsTileType(cur_tile, MP_HOUSE)) {
-					_error_message = STR_ERROR_CAN_ONLY_BE_BUILT_IN_TOWNS;
-					return false;
-				}
+					/* Clear the tiles as OWNER_TOWN to not affect town rating, and to not clear protected buildings */
+					CompanyID old_company = _current_company;
+					_current_company = OWNER_TOWN;
+					bool not_clearable = DoCommand(cur_tile, 0, 0, DC_NONE, CMD_LANDSCAPE_CLEAR).Failed();
+					_current_company = old_company;
 
-				/* Clear the tiles as OWNER_TOWN to not affect town rating, and to not clear protected buildings */
-				CompanyID old_company = _current_company;
-				_current_company = OWNER_TOWN;
-				bool not_clearable = DoCommand(cur_tile, 0, 0, DC_NONE, CMD_LANDSCAPE_CLEAR).Failed();
-				_current_company = old_company;
+					if (not_clearable) return false;
+				} else {
+					/* Clear the tiles, but do not affect town ratings */
+					bool not_clearable = DoCommand(cur_tile, 0, 0, DC_AUTO | DC_NO_TEST_TOWN_RATING | DC_NO_MODIFY_TOWN_RATING, CMD_LANDSCAPE_CLEAR).Failed();
 
-				if (not_clearable) return false;
-			} else {
-				/* Clear the tiles, but do not affect town ratings */
-				bool not_clearable = DoCommand(cur_tile, 0, 0, DC_AUTO | DC_NO_TEST_TOWN_RATING | DC_NO_MODIFY_TOWN_RATING, CMD_LANDSCAPE_CLEAR).Failed();
-
-				if (not_clearable) return false;
+					if (not_clearable) return false;
+				}
 			}
 		}
 	} while ((++it)->ti.x != -0x80);
@@ -1598,8 +1602,11 @@
 
 	do {
 		TileIndex cur_tile = tile + ToTileIndexDiff(it->ti);
-
-		if (it->gfx != GFX_WATERTILE_SPECIALCHECK) {
+		/* it->gfx is stored in the map. But the translated ID cur_gfx is the interesting one */
+		IndustryGfx cur_gfx = GetTranslatedIndustryTileID(it->gfx);
+		const IndustryTileSpec *its = GetIndustryTileSpec(cur_gfx);
+		
+		if (it->gfx != GFX_WATERTILE_SPECIALCHECK  && !(its->special_flags & INDTILE_SPECIAL_DONT_BUILD) && (it->ti.x >= 0) && (it->ti.y >= 0)) {
 			i->location.Add(cur_tile);
 
 			WaterClass wc = (IsWaterTile(cur_tile) ? GetWaterClass(cur_tile) : WATER_CLASS_INVALID);
@@ -1613,9 +1620,6 @@
 				SetIndustryConstructionStage(cur_tile, 2);
 			}
 
-			/* it->gfx is stored in the map. But the translated ID cur_gfx is the interesting one */
-			IndustryGfx cur_gfx = GetTranslatedIndustryTileID(it->gfx);
-			const IndustryTileSpec *its = GetIndustryTileSpec(cur_gfx);
 			if (its->animation_info != 0xFFFF) AddAnimatedTile(cur_tile);
 		}
 	} while ((++it)->ti.x != -0x80);