Cracked corner wall

Smithy99

Is it normal for plaster to do this? A small bit cracked and came away at the bottom last year but now it's cracking higher up too. We're redecorating shortly, what's the best way to sort it? Thanks. 

Alter_ego

Not normal. Is it an external wall? Stud wall? Load bearing? Old chimney breast?

Smithy99

It used to be an external wall but there's the extension on the back now. There's an rsj across the top

stuart45

Happens when the angle beads rust and expand. Needs to be cut out and replaced with stainless or plastic one.

Smithy99

Oh gosh, what's an angle bead? 

stuart45

Smithy99 said:

Oh gosh, what's an angle bead? 

One of these. Plaster & Render Beads Stainless Steel Angle Bead 3m - 50 lengths per box | Roofing Superstore®
The price is for 50.

Smithy99

Thank you, I'm just having a google!  Why would that happen?  I've seen damp mentioned but I can't see any other signs of damp in that area, could condensation cause it?  There's usually a sofa next to it and the unit in front, so not much air flow in that area I guess although there are gaps they're not pushed right up again it. 

Martin_the_Unjust

Hmmm if it’s normally hidden by furniture I’d be tempted just to fill it and paint over.

stuart45

It must be getting damp from somewhere. A lot of them are galvanised, and this often gets damaged at the start from the trowels, and it breaks down in time anyway. Probably condensation. They only started using them in the 70's when Carlite plaster started to replace the sand/cement render and plaster skim. Straight edges were used then to form a corner without the need for a bead, although some older places have a timber bead.

FreeBear

Check the roof and walls above the extension to make sure no rain water is getting in behind any flashing or felt & render. It may be that there has been a leak in the past which has caused the corner bead to rust away (can't see any evidence of one, so it might have been a tape joint). With the size of the gap, it may pay to pull the plasterboard off that section of the wall to see how much damage is behind. It will make a bit of mess I'm afraid and uncover more problems.

stuart45

If it makes you feel any better I've had the same problem. My wife has just told me to get on with the repair.