diff --git a/library/modules/Buildings.cpp b/library/modules/Buildings.cpp
index ab70944b7..f2312b05d 100644
--- a/library/modules/Buildings.cpp
+++ b/library/modules/Buildings.cpp
@@ -1114,18 +1114,21 @@ void Buildings::clearBuildings(color_ostream& out) {
     locationToBuilding.clear();
 }
 
-void Buildings::updateBuildings(color_ostream& out, void* ptr) {
-    //out.print("Updating buildings, %s %d\n", __FILE__, __LINE__);
+void Buildings::updateBuildings(color_ostream& out, void* ptr)
+{
     int32_t id = (int32_t)ptr;
-    
-    if ( corner1.find(id) == corner1.end() ) {
-        //new building: mark stuff
-        int32_t index = df::building::binsearch_index(df::global::world->buildings.all, id);
-        if ( index == -1 ) {
-            out.print("%s, line %d: Couldn't find new building id=%d.\n", __FILE__, __LINE__, id);
-            exit(1);
-        }
-        df::building* building = df::global::world->buildings.all[index];
+    auto building = df::building::find(id);
+
+    if (building)
+    {
+        // Already cached -> weird, so bail out
+        if (corner1.count(id))
+            return;
+        // Civzones cannot be cached because they can
+        // overlap each other and normal buildings.
+        if (!building->isSettingOccupancy())
+            return;
+
         df::coord p1(min(building->x1, building->x2), min(building->y1,building->y2), building->z);
         df::coord p2(max(building->x1, building->x2), max(building->y1,building->y2), building->z);
 
@@ -1135,18 +1138,24 @@ void Buildings::updateBuildings(color_ostream& out, void* ptr) {
         for ( int32_t x = p1.x; x <= p2.x; x++ ) {
             for ( int32_t y = p1.y; y <= p2.y; y++ ) {
                 df::coord pt(x,y,building->z);
-                locationToBuilding[pt] = id;
+                if (containsTile(building, pt, false))
+                    locationToBuilding[pt] = id;
             }
         }
-    } else {
+    }
+    else if (corner1.count(id))
+    {
         //existing building: destroy it
         df::coord p1 = corner1[id];
         df::coord p2 = corner2[id];
-        
+
         for ( int32_t x = p1.x; x <= p2.x; x++ ) {
             for ( int32_t y = p1.y; y <= p2.y; y++ ) {
                 df::coord pt(x,y,p1.z);
-                locationToBuilding.erase(pt);
+
+                auto cur = locationToBuilding.find(pt);
+                if (cur != locationToBuilding.end() && cur->second == id)
+                    locationToBuilding.erase(cur);
             }
         }