Spiders ate nocturnal. Leave the lights on in that room and they WILL go away.
Spiders are the most difficult pest to control by standard methods. You cannot often spray them directly for a contact kill with pyrethrins, so you must use a residual systemic product. The problem with these are that pests must first walk through the residue, then they later ingest while cleaning themselves.
Spiders do not clean themselves often.
Shihan, scmeehan. I'm the bug man