crack running across concrete floor near patio doors

Thanks for adding that suggestion Leo, I sometimes forget to say that.
However, I think we're already deep in territory that may be best left to real life.

There is a limit to the quality of information I can offer remotely and limits to what I should offer.
The OP has been advised to take independent professional advice in real life and that where I bow out.

I'm happy to comment on queries up to a certain point, but not to take jobs away from professionals in a recession.


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.
 


That suggests that the crack is inside the oriignal footprint of the main house and is not "outside" the patio doors, is that correct?
If my assumption is right, you have a serious building defect developing with your building and you need to assess this.
Thus I don't need to see your pics - you need to get a competent Chartered Engineer to inspect and advise.


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.