First plastering attempt

[Niscars]

I have reduced the size of a door opening and will be fitting plasterboard over the stud work. I am looking for solutions to finishing off over the plasterboard and patching into the existing plaster (looks like sand / cement with thin plaster coat). I've never done any plastering but it’s only a small area (2000 x 350). Any advice on what to use, what prep and how do I stop it cracking at the join please?
Many thanks.
Niscars

 

[David J Williams]

You will need to use scrim tape on the joints. You may be better to use a one coat plaster than standard plaster as it is easy to sand smooth. Have a look on YouTube videos of drywalling these will help you

 

[noseall]

and how do I stop it cracking at the join please?

A miracle? All the scrim in the world won't stop it cracking. We'd remove the immediate surrounding plaster and lap the plasterboard over the wood-masonry join.

 

[Niscars]

Ah, OK. So, on the pictured side I should go all the way to the right until the corner (only about another 4 inches) and screw plasterboard to the frame with dot and dab on the wall? On the other side, there is too much wall before the corner, so just cut the plaster back to block about 6 inches beyond the wood, neaten up and same again with a single piece of plasterboard?