I notice my new deck boards tend to bow upwards when wet (looking like channels). Worried about making it worse by only sealing the top surface.
Do you seal the underside?
What do you use for application to underside and the railing? Regular paintbrush? Pad applicator?
Plamen, we typically don’t seal the undersides, but it’s not going to hurt if you do want to seal them. If you have a second story deck, then the undersides can be easily coated by using a paint sprayer or pump-up sprayer. If it’s not accessible, then sealing them really isn’t an option.