Vertical crack in external wall

28 Jun 2021
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United Kingdom
Hi everyone,

I am in the process of (possibly) buying a property and the survey has reported a vertical crack in the exterior wall. I have attached some pictures.

This is a mid-terraced house in London, where rear extensions were put on after WWII. The crack runs vertically exactly down the line between our property and the one next-door. You can see from the photos that the mortar and bricks are different colours -- our mortar (on the right) is more yellow, whereas the other property's is more grey. This suggests to me that our property had its extension fitted later, but I can't be sure about that. Anyway, it looks to me like the crack has appeared between these two extensions.

Does anyone have any experience of these kind of cracks? Is it normal? I am trying to work out whether it's likely to be a building issue such as expansion/thermal movement etc or something more serious like subsidence because of drains.

Thanks very much in advance for your thoughts!
Screenshot 2021-06-28 at 15.19.10.png
Screenshot 2021-06-28 at 15.19.15.png
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Apart from stating the bleedin' obvious that there is a crack, what has your surveyor mentioned about it in terms of if its a good or a bad thing, age, consequences etc?

Looks normal to me
The tying in doesn't look that good. Quite common for a crack to form there.
Thanks Woody and stuart45. Honestly, the surveyor hasn't said much beyond saying it was very unusual, that if he had to guess he'd say the most likely cause was leaking drains, and (unsurprisingly) that we should get a drain survey and a SE's report. We're currently working on getting those sorted. Surveyor said it was a 3 or 4 on the BRE scale (5 being the worst), but all checks to walls, floors etc for subsidence were ok -- nothing detected -- and there doesn't seem to be any issue with windows and doors sticking etc so I think this is on crack width only. The survey itself recommended helical pinning as a repair, but if this is actually caused by the drains a more fundamental repair job would obviously be required before any stitching above ground.

For what it's worth, the maps of drains/sewers don't show any major ones below the property but obviously the smaller ones are everywhere.

Thanks again.
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Yours photos don't really show the details of the crack too well. Does the crack go through the DPC? Doesn't look that unusual where an extension joins another building.

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