Our new (to us) house has a damp foundation, it’s not an underground basement, it’s more like a first floor. We ripped out the drywall and flooring, had a perimeter drain and sump pump put in. Water is worse now, but I’m hoping the people who installed the drain and sump pump will fix it. Fingers crossed. Im not doing anything until it’s mitigated, but when I reinstall the drywall, I’d like to take extra measure against mold. Surprisingly, it wasn’t moldy when I pulled it out. But can I paint the back side of the drywall and with like drylok or similar before installing it? Or is this a terrible idea. Or just unnecessary? I’m using foam board insulation and a vapor barrier on the foundation walls. I know there is waterproof gypsum board you can buy, but it expensive.