I'am assuming that the cracks you are getting are straight one's that usually follow the joints of the plasterboard.
To be honest with you,this can happen unfortunately.

You'll probably get some spreads on here screaming your plasterer hasn't used scrim tape on joints but even using scrim tape is no guarantee that cracks will never appear.

This time of year is especially bad as most builders merchants stock all their boards in big cold,damp units so the boards can swell up a bit with the excessive moisture in the air.
Stick them on walls in a nice dry warm house and they will dry out and shrink.....this could be the cause of your cracks.
It only takes the slightest bit of movement for cracks to appear.
The cracks are perfectly manageable though,just get yourself a small bag of Gyproc Easi-Fill joint cement & some very fine sandpaper,mix a bit up then grab your wife's credit card to use for a spatula apply it well into the cracks & scrape off as much excess as you can as this will minimise sanding.
Let it dry thoroughly & then just a quick flick over with the sandpaper (if needed) & then re-decorate.

Carl.

Hi would be interested to know if one coat plaster was used,also are cracks appearing as straight lines or where the plasterboard joints are?? crazing and cracking would occur if only 1 coat applied,I would suggest you get a different plasterer to look at it for you in order to ascertain the problem. We hope this helps a bit, but without seeing it ouselves it is difficult to suggest a solution.

Plaster work will normally crack as when it dries it shrinks, This can vary from a few cracks to lots, it all depends on drying times, How hot the property has been etc. Was the area was prepared properly? Was there cracks in the wall before? was the wall sealed before plastering? Was the second coat applied too soon after the 1st coat? It could just be down to movement in an older house. But whatever it is your plasterer should have pointed out there maybe cracking appear as and when it fully dried. Not necessarily your plasterers fault that its cracked but you should have been made aware that it might happen. Phone him and explain the problem, but it sounds like it has just dried too quickly, A problem when plastering in the winter as the heating is on and force drying the plaster.

This is unusual on plasterboard.Do the cracks follow the plasterboard joins or are they everywhere? If they follow the joints,then the joints havent been covered with scrim.If they are everywhere then i would suspect that either, not all areas have been boarded (were you at home when this was done?) or you have been given a 1 coat job and it has been too thin and dried too quickly.The plasterers on here will maybe give you more info (carl melady knows what hes talking about) but like i said,this is unusual on board if the tradesman was a bona fide plasterer.

Hi there, it's to much talking... It's a builder fault ! Using wrong products or none joint tape on plasterboards. If your walls are cracking after 4 months you should ask those workers to come and fix it free of charge as £1100 pounds it's a lot of money, special for bad job. We builders must know what to use and where if we are professionals. I think you should get some money back and hire again proper plasterers not someone who think he is.

Sounds like no tape was applied, the plasterer may have filled bits in with adhesive and not taped the joints where the board and adhesive meet, I would get them back in to do it properly.. they should tape the full wall with some 1 metre wide fiber tape and re-plaster to sort it out. Hope you get it sorted :)

I can't see why the plaster should be cracking when on plasterboards. Are the lines horizontal and vertical? This could be due to not using scrim tape over the joints or not putting enough adhesive dabs on the wall they should come back and fix any problems though