Should painted stair treads be stripped before repainting?

Question

I would like to paint my staircase black (treads) and white (risers). I would like it to look something like this:

When I bought the house the staircase was carpeted. After removing the carpet and underlay there was quite a bit of old glue residue that the carpet fitters used. There were also a lot of staples, which I have removed. From what I can tell it looks like it originally had a carpet running just up the middle, with gaps at the sides which were painted white:

There is also a mini landing, which I want to paint black. Is there anything special I should do here ? I wondered about laying plywood over the whole area first ?

So far I have done quite a bit of sanding and filling, but I am not sure how to proceed from here.

My questions are:

Should I sand (or strip?) it all back to the wood?

How should I prepare this staircase for painting?

Answer 1

You don't need to strip to bare wood for painting. You do need to sand well enough that old paint lines are gone. They will make an appearance in your fresh coat, otherwise. This will likely expose some bare wood, so you'll need to prime properly per the instructions on the paint of your choice.

Other prep mostly involves filling or sanding out defects, scuffing remaining glossy paint, and removing any oils or other problematic substances from the wood. Basic paint stuff. As KMJ suggests, take appropriate precautions if you suspect the presence of lead paint.