Can I use caulk instead of mud?

if you use caulking on it you will regret it. first of all you can't level evenly level the caulking so the crack is not noticeable and even though the caulking is flexable it will crack again. also even if you prime the caulking it will be shiny after you apply your finish coat of paint and if you are using a low sheen paint it will look terrible.

the only thing to do is tape and mud it. alot of people use the fibre glass mesh tape because it is easier but i like paper tape myself. i like to thin down a small amount of joint compound and soak the tape in it. then apply to your wall and smooth it out. once that has dried apply 2 - 3 thin coats of joint compound. if you want you can sand between each coat depending on your finishing ability. on the final coat have a spritzer bottle with water in it and as you are smoothing out the joint compound give it a light spray of water. it will stop your mud from drying so fast and give you a nice smooth finish with very little sanding. just make sure you feather the edges out well, a sanding sponge works great for that.. then apply your primer and finish coat. i would hate to see the work of that one professional painter that would use just caulking. he would never work on a job with me.

I just did a wall in a bathroom where the man put ina shower. The wall had a crack in it that was big.I used the caulk and a damp sponge to do the job. The crack was big enough that I had to do it again the second day with the same tools.It is painted now and you could call it a no show Jones.

Go with the mud and sand it. The result will be less noticeable than using caulk.

Actually, paintable caulk is EXACTLY what you should use because it flexes. You can spackle a hundred times and the crack will keep coming back.

You might be OK using caulk as long as the gap doesn't continue to move. Just to be sure use an "elastomeric" caulk. DAP makes one.

tape and mud