
@DietCanesSauce Also, if there’s not too many steps you might want to have the tops of the stringers covered with a waterproof membrane. This would require taking all the treads off so maybe not feasible. Water can sit on stairs for long periods and make its way into the wood which will eventually rot. The membrane reduces that penetration. A lot. You only put it on the top horizontal surfaces, basically under the treads. Never on the bottom surfaces.

@DietCanesSauce @merde
You’d still have to remove the treads.
To be clear, stairs have been built for a long, long time without a membrane, which I’m pretty sure is a somewhat new practice.
I wouldn’t do it as a retrofit unless it was only a few steps. I did it on mine after my last stringers rotted.