how to fix this crack- pictues in job posted

There is usually 2 types of cracks, one would be a due to expansion and contraction. The other one would be a structure crack, a structure crack usually starts from the bottom carry on all the way to the top of the wall. You usually see a bigger crack on the bottom carry on to the top, but as you get higher, the crack is thinner. Most of the time would not be the case. If it is a very uniform crack, it is likely just the brick work being expanded and contracted due to temperature change. If this is the case, all you need is to open up the crack slightly with a knife and get it pva'd and fill with a flexible filler like easifill. p.s. damp can contribute to cracks yes! this is an entirely different subject... You need to get it inspected where the damp is coming from, is it from external, is it condensation, gluttering etc? Get that fixed then fix the crack.

Cut out crack with knife or trowel. P.v.a over and refill with easy fill sand if needed wen dry

These cracks are typically caused by shrinkage and or movement in the render and are quite normal. you can simply fill them and then paint over if the structure is solid enough or you might need to use a fine tape over the crack once you have filled, then skim a fine layer of filler then paint once sanded with a 120 fine sandpaper

Hi, All buildings have an amount of movement through heating up and cooling down. Cracks in plaster do appear and it’s nothing to worry about unless it starts to grow significantly. If the crack is horizontal this can be a sign of subsidence. The only way of finding out will be to do a survey of the building and the surrounding grounds. The damp issue could also be identified at this time.