Cracks between the main house and the extension (rear)

[timsterboss]

Hello,

I am a FTB and offer has been accepted already. During the building survey, the cracks have been mentioned in the report and I am not sure how severe this is and how much this would affect in terms of cost and the structure of the property, safeness, etc.
Two storey extension towards the rear of the house. Where the main and the extension meets it's been repointed.
The report mentioning about "differential movement" and penetration damp on the junction. Similarly, seems like roof (where main and the extension joins) is affected too.

Could anyone please advise on the cracks that are appearing on the side of the external wall as shown in the images? Could these due to foundation or subsidence? Really hoping these wouldn't cost too much to repair/replace.
Some cracks at the front of the property as well.

 

[RonnyRaygun]

Unlikely to be subsidence. Cracks where extensions meet original buildings are common for a number of reasons including settlement, thermal, shrinkage, and subsidence or heave. The last two are of most concern but are usually obvious as the cracks are larger at the top or bottom and not of a linear size.

Your mortar joints look pretty much the same size all the way up so more likely to be shrinkage at the joint. It’s good practice to use a sealant at the junction rather than mortar but seems to be rarely done.

Also common to get cracks under windows due to the inherent weakness of long, thin masonry panels. Common these days to install bed joint reinforcement in such panels to prevent cracking.

 

[timsterboss]

Thanks for the comment! I was hoping it was not subsidence, I've heard it's really expensive to repair it.
We are thinking to get a structural engineer survey, would this be necessary? Wanted to make sure the house is structurally stable in the future.
Why is the second image more concerning than the first one?
We are thinking to get rid of the bricks in the third image.

 

[RonnyRaygun]

Who said the second image is more concerning?

Did the surveyor recommend a structural report? Wouldn’t be a bad idea either way as they may well be able to see something that we can’t from a couple of photos. Plus they have the relevant insurances etc.

You could tooth in some new bricks but if you do I’d recommend Helifix in the joints every third course for 450mm past the full width of the panel each side otherwise chances are it will crack again.

 

[timsterboss]

You could tooth in some new bricks but if you do I’d recommend Helifix in the joints every third course for 450mm past the full width of the panel each side otherwise chances are it will crack again.

Do you mean the side of the wall (image 1) or the front (image 3)? or both? Would installing Helifix prevent further cracking?

The surveyor said it would be good to get a structural report to have a deeper understanding or inspection of the structure.

Thanks for the comment!

 

[RonnyRaygun]

I was talking about image 3.

 

[timsterboss]

Thanks a lot!