External cracks in flat with history of subsidence - monitor or tie? All manner of questions and solutions to problems and issues surrounding the subject of brickwork, blockwork and stonework

[Aewalker]

Hello,
Bit of background - I've just bought a flat and have since found out it was underpinned in 1990 (subsidence due to a leaky water main). A patch of brickwork at the front of the house has obviously been repointed at some point (not in the last 10 years according to previous owner) but there are visible zigzag cracks along the mortar joints. Homebuyers survey stated "evidence of past structural movement" but "does not appear to be progressive".
My builder has suggested helix wall ties and repointing. But I want to monitor so I can find out if it's still moving.
My question is - can you still monitor movement if you have new wall ties put in and the brick work repointed? I imagine the wall ties won't stop subsidence if it's still moving so I could still go ahead with the work in the mean time? And just take the hit if I find out it is still moving. The internal walls are damp hence me wanting to repoint ASAP.

Thanks in advance for any help!
Amy

[welsh brickie]

you can monitor movement with glass slides fixed across the cracks, but I suggest you have a structural engineer check it for you, the report will not only give you peace of mind, but you can show the next owner the report if you decide to sell it

[Aewalker]

Thanks very much for getting back to me. Much appreciated.
Yes, I was thinking the same about getting a stuctural engineer to have a look. My only worry with that is that I might pay a few hundred for a report which says I need to monitor the cracks..! I'm not sure what the engineer looks for during a survey.
As the glass slides fit across a crack I presume I can't repoint anywhere or put ties in? Won't they skew the results?
Thanks again!
Amy

[welsh brickie]

you may be paying for works that don't need doing, Its best to have a report done, and on the basis of the report have the works done by a builder who can accurately quote you accordingly, It saves you money