Shrinkage or Subsidence? (External Garage)

[JimmyB18]

Hi all,

Before contacting a structutral engineer, I thought it best to ask for advice from this forum.

I've noticed this external crack on our external garage (it might have been there for ages, though!). Googling it points towards possible subsidence with it being stepped, though I'd appreciate any help.

I've tried to post a range of images below from zoomed in to considering the whole wall:

 

[blup]

That is just some thermal related mortar movement. Its the vertical cracks you need to worry about, especially those that go through the wall. Let us know what your struccy says though.

Blup

 

[RonnyRaygun]

It’s so minor I wouldn’t even call an engineer out. A stepped crack can indicate localised subsidence but it’s so minor it’s not worth worrying about.
BRE Digest 251 would suggest it’s at worst a category 1 crack and requires no action, or just filling. https://files.knowledgepoint.org/uploads/14304828603790347.pdf

The only way a structural engineer could confirm subsidence would be but getting trial pits dug, and soil tests and crack monitoring carried out, all of which are expensive. You’d then have battle with your insurance company although you’d have to pay any excess anyway.

You could monitor the cracks yourself using monitoring studs placed either side of the crack and taking monthly readings. Significant growth of the crack in the summer months could indicate subsidence if trees are nearby and the soil is clay. Slight cyclical movement is nothing to worry about.

In any case, for the crack to have been caused by foundation movement it would have to reach the foundations. If it stops at a higher level it’s not subsidence.