Crack In plaster

[diycooper]

A crack appeared in the plaster by my stairs. I scrimmed it and went over with Easyfill. Then sanded and painted. However the crack has come back. There is nothing below the wall and its not supporting but there must be movement somewhere. Need to get rid . What is best way to try and solve this from coming back. Smash out fill with caulk ?

 

[zenonithus]

did you cut out the crack in a v style and did you cut it real deep? Try cutting deeper and wider.

 

[misterhelpful]

Out of interest, was there originally some kind of cupboard under the stairs that has been removed at some point?
I've seen this happen in a few houses where some framing, not really considered as structural, is removed from under the stairs. This can lead to a lot of movement in the stair strings and result in a lot of localised cracking. If this is the case, you may need to bolt through the underside of the strings into the side wall to reduce movement. (That may be necessary, in any case.)

It sounds like you did the most obvious basic repair but, as mentioned by zenonithus, gouging out and filling deeper can be a lot more successful if you haven't already done so.