Any idea cause of these cracks?

Hi looking was looking at a IP around Ipswich QLD area. Any idea what can be the cause of these cracks in ceiling and walls?

 

Poor workmanship

 

Settlement movement, usually a sign of poor drainage or reactive soil. Pretty minor

 

Minor cosmetic cracks due to settlement or reactive soils expanding and contracting as moisture content varies as @DaveM says. Nothing a $2 tube of acrylic filler can't fix.

 

Thanks.
I thought so but is it ok if its built on a black soil or reactive soils? No major issues later on? let say in 5 to 20yrs time?

 

Houses on reactive soils/clay will always move as soils heave with moisture/drying process. If its brick veneer then you will get some movement cracking over time in brickwork (which is fine as the brick isnt structual), and internal cracks will reappear and need patching/painting every now and then. All part of home maintenance.

 

Depends on the area in Ipswich,some are built over old interlined ex underground mines,then you have the black soil flood zones areas where every time it rains you will have movement..But looking at those pictures and they would be above the 20 years range and no signs of termites then just a sealant gun a few high quality tubes that would look new very quickly with paint..imho..

 

movement on those, some may be design or workmanship.

no issues, cosmetic usually.

 

I'm going to say this one is more work mans ship
The cornice guys have been a bit slack by the looks. Cornice cement is strong stuff and the way those are coming off looks like they've taken a short cut or two, plus the butt joint in the first photo is a giveaway. You'd normally see a cornice on a 45 angle for a semi professional job.

 

I've found a common issue with settlement movement is the external loadbearing walls supporting the roof trusses settle relative to the internal non-loadbearing partition walls. The bottom chord of the truss then puts a slight pressure on the partition wall (which should be non-loadbearing) and subsequently deforms the cornice..
Without looking at the house, I'm pretty sure it will get worse before it gets better..
P.S. Ipswich can be a bit of a hotspot for reactive soil.