Mortar cracks above window frame

Bingjamin

Hi all, having a bit of a panic over here that my house may have structural issues/subsidence. Have recently noticed the below cracks above my living room window. House is about 30 years old. Is this anything to worry about? 
Thanks,

morhen

How old is the house?  Is there a chance there isn't a lintel above the window?  When old (structural) wooden windows get removed and replaced with pvc, there isn't the same amount of support which can lead to sagging and cracks.  Window installers shouldn't install a pvc window if there isn't a lintel, but some cowboys don't care.  The good news is that if it is a missing lintel, any decent builder will be able to put one in for you easy enough.

Bingjamin

It was built in 1990. Unsure about whether the lintel is missing. Had just assumed it would just be there. How could I check?

My real worry is subsidence. Do you think it could be this? 

koalakoala

More likely to be what morhen says. 

EssexExile

We had the same above one of our windows. Exactly as Morhen said, windows had been replaced with no thought about the lintel. When we had new windows put in they just put an angle iron in to support the bricks above. Are there any cracks below the window?

stuart45

Looks.like there's a tray installed, but probably a concrete lintel for the inner skin and nothing for the outer. Quite a common problem.
Something like an L10 lintel would be OK.

Bingjamin

Thank you all, this has definitely eased my fears of the worst.

In answer to your question EssexExile there is some cracking underneath, not to the extend of above the window. Did you have this too?

I don't have any idea when these windows were replaced, if at all. We only moved in 8 months ago. Why would it only happen now? 

stuart45

Put a photo of the cracking below the window up. It could well be thermal if it's even and doesn't go through the DPC.
I doubt if they are the original frames, as plastic aren't built in (timber usually are) so you need an external lintel in place. With a timber window you could build on top of it back then.

Bingjamin

Here you go. Much less below the window. 

On our homebuyer survey it seems as if the lower cracking is mentioned but no the top. Telling me the top has appeared since we moved in not sure how relevant that is. Need to confirm with the surveyor on Tuesday. 

Any feeling what might be causing it?

stuart45

Could well be thermal cracking. Brickwork expands and contracts with temperature changes, so on a hot day it will expand and at night it contracts and can crack. The window area is a weak spot in the brickwork on long runs.
The area above the frame can often take a few years before it starts to fail.

Bingjamin

Okay, thanks. What do you reckon, just repoint and hope for the best?