Cracks... When do they become something to worry about?

[Pigleychez]

Hi, we had a extension built last summer and since then have been noticing more and more cracks appearing. Mainly round door frames, where walls meet ceilings, skirtings. Etc
I expected abit as things settle but it seems to be getting more and more.

When does it become a worry and something I should get checked?
Is it because the temp differences over winter inside and out?

Any advice/ thoughts would be great as I'm starting to get concerned the house is subsiding!

A structural engineer I knew said that the time to worry about a crack is if you can fit a pound coin in it. That's not to say you shouldn't investigate/sort earlier stuff, but that's the width when something is clearly a problem.

Well that's made me panic as there's a crack in my chimney breast upstairs that is now at the pound coin width! I know what the cause is, just can't afford to fix right now and my insurers won't cover it. Keep worrying about it in the middle of the night.

Sorry!! That was just a conversation I had with a friend who happened to be a structural engineer when I was buying a old flat, so it was v much a rule of thumb opinion, not set in stone for every specific circumstance.

Here is some good background information. Generally speaking cracks have to be pretty major before there is a concern about structural failure.

It sounds to me that your extension is merely settling into its foundations. Subsidence cracks tend to appear (and worsen) very quickly and be thicker at the top than the bottom.

We had an extension at the end of the summer and our builder said he'd be back in a year to snag and skim . I think its stuff settling. Hope your builder comes back to sort it.

Thanks everyone. They are only hairline cracks thankfully but will keep an eye on them.
Frustrating as cosmetically it looks awful and I thought all the decorating was finished.