My ant problem (catch 22)

Hello everyone, I pulled up a wooden raised garden border and in the process stirred up a carpenter ant colony inside. I drag the wood as far away as I can and a couple days later I sprayed the lawn with Bayer insect killer. Just over the weekend I found about 10 ants in m bathroom. And last night another 6-7. Now I know I'm supposed to seal off the point of moisture and then bait/poison them. The moisture is from the shower water seeping through the tub walls (they haven't been caulked yet). I want to seal it up but then I won't have a way to get to baiting them.
Any suggestions?
Thanks in advance.

My ant problem (catch 22)