diff --git a/src/game/rooms.js b/src/game/rooms.js
index f2bac2e1..2cda00f5 100644
--- a/src/game/rooms.js
+++ b/src/game/rooms.js
@@ -1068,7 +1068,7 @@ exports.make = function(_runtimeData, _intents, _register, _globals) {
             return C.ERR_INVALID_TARGET;
         }
 
-        if(_(runtimeData.userObjects).filter({type: 'constructionSite'}).size() + createdConstructionSites >= C.MAX_CONSTRUCTION_SITES) {
+        if (_.size(register['constructionSite']) + createdConstructionSites >= C.MAX_CONSTRUCTION_SITES) {
             return C.ERR_FULL;
         }