new plaster cracking

[Steve]

Had a bedroom plastered on friday. A couple of the walls are now completely dry, a few are still damp. On a few external corners (the room is an awkward shape with plenty of external corners) the plaster has cracked on the edge of the metal beading - only on one side in each case though. The plaster on the metal beading is proud of the rest of the plastered surface. Is this normal / to be expected? The plaster hasn't dried any quicker on one side, its all still damp. The plaster aint gonna fall off is it? (This has happened in this house before, i kid you not)

 

[noseall]

if the existing external corners had the old fashioned wooden stop beads ( yes wooden!!), then it is not unusual for this to happen.
it's a result of the expansion then contraction of the wood due to the damp plaster.

once settled it shouldn't crack again. maybe some fine filler once everything is dry.

 

[Steve]

Yes, the old corners were wooden, and the plaster had been stopped to them with a slight bevelled edge, a perfectly straight one too. Gotta admire the plasterers back then, at least they knew their trade. The builders didn't know what 90 degrees looked like in this house.

Your explanation makes sense, I shall leave it a week and go round with some filler before i paint.

 

[2face]

old plaster ??

may be another cause