In my bathroom remodel, there are two small windows where the shower will be that I will be removing. On the exterior is hardiboard siding. I have not removed any siding yet to see what is underneath.

When I remove a window, what should I be using as part of the interior and exterior cladding. Tar paper, Tyvek, vapor barrier?

Any advice on making sure that it is water tight?

Thanks, Dave

I'm assuming there are no new windows or window going back in?

Before you tear out those windows you need to make sure you can get the same Hardi siding.

I can only guess as to the type of weather barrier that may have been used. Just cover the outside with the product that was originally used once you do tear out those windows.

Same for the interior. Not knowing your geographic region makes any advise unreliable.