Attaching PVC trim to metal studs

Factual Questions
1

Every once in a while (used to be monthly, now its every few years), I have a water problem in my basement. Usually its a sump pump failure or something along those lines. I’m pretty confident I have fixed the water problem for good, but Mr. Murphy visits every so often and ruins my plans.

Now that the water problem is (mostly) taken care of, I am putting up walls in the basement to section off a workshop and utility room. My plan is to use 8" x 1" PVC boards for baseboards, with metal studs and sheet rock. I’m anticipating a 0.5" x 1.0" rabbet in the back of the PVC, and resting the sheet rock in that rabbet. My highest water has been 6", so I’m not concerned about the sheet rock getting wet at that height. The PVC can tolerate being wet, as can the metal studs. I’m happy with my water-resistant wall plan.

My problem is how to attach the PVC to the metal studs. I have used PVC over wood - using Coretex screws with plugs - with wonderful results. Those screws won’t go into metal studs. I could use long, fine drywall screws, but that will leave the screw heads exposed in the PVC, and the head of a drywall screw isn’t the best thing to hold PVC. There may be some sort of adhesive, but I’d prefer not to glue the boards if I can help it.

Is there some sort of solution that I’m not seeing here?

2

Trim screws are the usual solution for something like this. They’ll go into the metal studs, and you can cover the screw with wood putty.

3

Just use the hard point screws made for steel studs. Countersink the holes, and then fill them with silicone caulk, or if you don’t countersink just cover the head with the caulk. Those screws are very corrosion resistant. Also run a bead of caulk along the bottom of the trim and/or steel plate for the studs, you don’t want moisture collecting under the plate.