Cracks at plaster corners: shrinkage or movement?
Not every crack in a new house matters. How we decide whether corner cracking in a Clyde North home needs an engineer.
In short: Fine cracks at cornices are common in new homes. The major corner cracks we recorded at a Clyde North fixing inspection were different, and the report referred them to an engineer.
Two kinds of crack
Shrinkage cracks follow plaster joints and cornices as the timber frame dries. They are fine, stable and cosmetic. Movement cracks are wider, often diagonal from corners of openings or along wall junctions, and they can grow or recur after patching.
What we saw
At a March 2026 fixing stage inspection in Clyde North, the cracks at several corners were significant enough to be recorded as a major item. The inspector's note was that soil movement or a structural issue could be the cause and that an engineer should investigate.
Why soil matters
Slabs in Clyde North are designed for reactive clay. When moisture under one part of the slab changes faster than another, the slab moves unevenly and the frame and plaster follow. Drainage, plumbing leaks and garden watering all play a part.
How an investigation proceeds
We measure crack widths, map their pattern, check doors and windows for binding, take level readings where useful and look at drainage around the slab. The report says whether the pattern suggests movement and who should look next.
When to call it in
If cracks are wider than a couple of millimetres, recur after patching or come with sticking doors, have them looked at before painting over them.
Written by our local inspection team from work carried out in Clyde North. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
