diff --git a/code/controllers/subsystem/mapping.dm b/code/controllers/subsystem/mapping.dm
index ceb2fae998..29762338fb 100644
--- a/code/controllers/subsystem/mapping.dm
+++ b/code/controllers/subsystem/mapping.dm
@@ -444,7 +444,7 @@ GLOBAL_LIST_EMPTY(the_station_areas)
 		GLOB.the_gateway.wait = world.time
 
 /datum/controller/subsystem/mapping/proc/RequestBlockReservation(width, height, z, type = /datum/turf_reservation, turf_type_override, border_type_override)
-	UNTIL(reservation_ready["[z]"] && !clearing_reserved_turfs)
+	UNTIL((!z || reservation_ready["[z]"]) && !clearing_reserved_turfs)
 	var/datum/turf_reservation/reserve = new type
 	if(turf_type_override)
 		reserve.turf_type = turf_type_override