distance from wall to reveal

[Eddie10]

Hi, next question!!
on said extension, on the wall coming out from original house I would like to fit the patio doors. does a 675mm pier have to be built from the wall?, same as distance from external corner to the door opening.
Hope that makes sense..
there will have to be something as the lintel has to be sited,

 

[cjard]

How thick is the perpendicular wall? How wide is the opening? What is above the lintel?

 

[Eddie10]

Its joining onto a 9in solid wall. The reveal i would like to be 2.4 ish metres. Its single story so it will be 3/4 courses of brick then the roof,which is pitched an tiled.