Internal wall cracks

[Daisy1996]

HI, this maybe a really daft question but when do cracks in walls become structural? ive got what’s looks like a 1mm slightly diagonal 1.5 meter long crack in my internal plaster. it’s covered by wallpaper at the moment. It easily shows during the day in the warmer weather by creasing the wallpaper then mostly goes in the evening when it’s cooler outside. Its an upstairs, gable end cavity wall south facing so gets the sun all day. It starts roughly at the bottom of a windowsill up towards a chimney breast and looks like it follows up the side of the chimney a little.

The bottom of the crack steps out a tiny bit but I think the plaster has blown. it’s original 1950s, very thick and sounds hollow in places.

we had a much shorter similar crack looked at by a structural engineer a few months ago and he said that was due to old plaster and the heat. I feel like a really wasted his time and he was lovely so feel reluctant to call him again so soon

Theres also a 1mm wide horizontal crack at the top of the window on the same wall that’s been there a couple of years, though when looking at it yesterday it is longer than it was. window opens fine, there’s no cracks showing outside

 

[jj4091]

You don't need to worry if the wall paper is not splitting the same as the crack. If it's a concern remove the paper, fill the crack and redecorate.

 

[Daisy1996]

Thank you. Waiting to hear back about some quotes to have the whole wall replastered as it’s hollow in quite a few places. We will take a few chunks out to check the wall underneath once we have confirmed when the plasterer is able to start. Hopefully the brick is ok.

 

[^woody^]

Cracks are defined as structural when they affect the performance of the structure - walls wobble, doors and windows jamb or suchlike. Cracks which are "just there" may be just cosmetic or may lead to other damage (water getting in, plaster falling off.

The relevance of any cracks will depend on several factors.

Plaster cracking, or blown plaster may be an age thing, its normal, but if there is cracking in the wall, then that may need looking at as it could cause any replaced plaster to crack again.

Without viewing the cracking, the location, both sides of a wall and wall connections, its not possible to determine the possible cause, relevance or remedial works required.

 

[Daisy1996]

Thanks for replying. You’ve said plaster cracking because of age is normal is good to hear. As someone who has absolutely no idea about anything to do with this my mind automatically thinks there must be a serious reason for this to happen