Grit your teeth, get on your knees, and follow the b****rs. If not, try dusting all round the wall/carpet join in the area. They wouldn't normally be active at this time of year, so they've been disturbed by your roadworks probably. Do you have a solid floor or wooden floorboards? If the latter, they could be coming up almost anywhere under your carpet, if the former, they're probably in the wall cavity, and are coming in under the skirting board. Sorry, that's the best I can do!! Good luck.