said by garys_2k:
I think he just wants to seal the raw edges, but allow water that finds itself under his floor to be able to flow to the sump. Also, presumably, water ON the floor should be able to flow through the slots and into the sump, too.
Yes, seal the raw edges.
A PT would trim could work, that's another idea to contemplate.
said by robbin:
Go to a good sheet metal shop and have some custom pieces made to protect and reinforce the edges.
Here everything custom is exceedingly expensive.
The edges don't need reinforcing anyway, so the PT wood is a simpler material if I make a trim. Thanks though.
Overall, the idea of a trim/frame is pretty good. I'd cut a bigger sized hole to accomodate the extra width added by the trim of whatever material I end up using. The final floor can still extend over that trim so it's not visible.