Ridge on plasterboard joints in ceiling?

justaquestion

Hi folks,

From the time I bought the house twenty years ago, I have always had this problem in ceiling. You can see the plasterboard joints in ceiling and there is a little downwards ridge along the join that protrudes a few mm downwards. You can pick this little ridge away with your finger tip, and both plasterboards do seem level enough then albeit with a small space of a few mm wide.

Probably painting over in past (just once) has not helped probably made the ridge a little thicker.

Anyhow about to paint ceiling soon, how do I deal with this, sand the ridge down to its level with plasterboard and maybe use this?

http://www.screwfix.com/p/no-nonsense-plasterboard-joint-tape-scrim-48mm-x-90m/68520?_requestid=830098

Then just paint over or is there some other way I need to do it?
Thanks for any advice.

flashg67

I have one on my wall which you've made me study again! It may already have scrim under the plaster skim which will need removing first then re-scrimming and filling with a fine surface filler, sanding then painting over