Thank you for your answer, it helped me to find that I wanted to do var sources = Game.spawns[NomSpawner].room.find(FIND_SOURCES); for (var j = 0; j < sources.length; j++) { var chemin = Game.spawns[NomSpawner].pos.findPathTo(sources[j].pos); for (var i = 0; i < chemin.length; i++) { Game.spawns[NomSpawner].room.createConstructionSite(chemin[i].x,chemin[i].y, STRUCTURE_ROAD); } } Now everything works