Concrete Block Extension Connection to Old Slate Wall

[JACKROGERS7]

i am wondering if anyone can help. i am an architecture student who is curious on a connection between an existing old slate building and a new extension .

any help/ advice would be massively appreciated

My Project Includes a 2 story old slate building located in the lake district from the 1800s (Slate external apperance ).
The current wall build up includes a 575mm thick slate wall with 25mm of internal lime plaster.

i want to add a 1 story lean to roof concrete block extension (as the main load bearing walls) along the eaves and gable wall.
The extension wall build up from inside to outside is :

100mm concrete block wall
100mm insulation
50mm SureCav Cavity
110mm slatestone wall

Question : does anyone have any advice on how i can 'fix' a concrete block wall against a slate wall.
I know its not the best but i asked AI as i was clueless which suggested a 10-20mm seperation gap which would include wall ties and mineral wool insulation.


i have attached a corner floor plan for the Image to explain the colours

1. Light green is a corner wall of the 575mm existing slate wall with 25mm internal lime plaster

2. Dark green - is the 110mm slate wall which is used to match its surroudings
3.black layer - is a 50mm cavity using surecav 50
4. pink layer - is a 100mm insulation layer
5. blue layer - are the 100mm concrete dense blocks