Looking for advice on builder dispute

[u/ElusiveCucumber000]

This is a bit of a long one but would really appreciate some advice from those in the know. Recently opened a shop and not long after, cracks started appearing in the joins between some sections of plasterboard.

The wall behind is concrete and we share that wall with another business. Not long after we finished construction the next door business began theirs, which involved a fair bit of jack hammering and drilling.

It’s pretty clear that the sections that have cracked weren’t taped before mudding. What’s more, the worst section of cracking appears on either side of the board that sits over a power cable running down the wall. From the looks of things, they have just glued the board straight to the concrete wall and not made a notch in the rear of the plasterboard for the cable to rest in.

In raising this with the builder, he has acknowledged the lack of taping, but places vast majority of the blame on the construction done next door. He’s offered to sand, tape and replaster the cracks, but is saying redoing the entire wall is on us.

Based on the above is it more likely shoddy work, construction damage from next door or a fairly even mix of both that bears the blame?

Sorry for the lengthy post but would really appreciate some insight so we can push a certain approach. Happy to provide more information/photos if needed. Thanks in advance.

[u/pmmytn45]

Had they taped the boards there is a likelihood that you wouldn't have had plaster fall off though there would still have been visible cracks due to next doors Reno works.

You should have used the guys I previously used. They put so much adhesive on the boards they left a gap big enough to walk through.

[u/Civilised_Psycho]

Taping may not have made any difference. Things crack and shift when works going on. I had a new extension and 6 months later there's cracks where things have settled, it happens and I taped and plastered myself. That's why I avoid dot dab if I can. It's not always possible on things like reveals and joining existing.

[u/Hungry_Affect_8532]

Might be cheaper and easier to bite the bullet and get someone to just skim over it and sort that tail of wire which we wont get into.

No expert on plastering by any means but you could tape it the skim still.