I'm over at my grandparents house and they have 2 large protruding cracks in what I guess is butt between two drywall pieces. I scraped the crack a bit with a paint scraper and to my surprise pieces of 'plaster' came off and behind it is what seems to be drywall but no tape and no butt.
They said there might have been wallpaper painted over, however that does not seem to be the case as I didn't 'see' any wallpaper in my scraping.
So to continue with the fix I widened the cracks to the point where none of the 'plaster' was falling off. In one location it was slightly less than the width of a piece of drywall tape, and in the other it was slightly more at one part.
I filled the cracks thus far with joint compound with a slight feather, and will most likely sand this so its entirely flat after it finishes drying so what we are left with is a filled crack area with no protrusions. Then I will most likely apply another coat of joint compound this time feathering it out wider so that it is not noticeable.
My question is, after I sand the first and currently drying coat, should I apply tape or mesh (normally I would do this if it were a small no protruding crack and I didn't have to widen it, or if there was a butt)? There is no seam in the drywall behind it, and I think with adequate feather I can hide the crack seams. I suppose if I did have to mesh or tape it on one I would have to use two pieces of mesh side by side to cover the entirety of the area.