Building gable end onto cavity wall

[loldollar]

As part of a loft conversion (hip to gable) I am looking to build a new gable end from timber on top of the existing cavity walls. I was wondering if anyone can point me in the direction of detailing for this type of construction, specifically fixings (timber onto brickwork), dpc detail and any other important points.

 

The existing cavity wall is brick/brick imperial with an 80mm cavity. My aim is to keep the studwork flush with the inner face of the inner leaf. The gable end will have a hung tile finish. Mainly my questions are around whether the outer leaf can/should bear any load and can the timber encroach over the cavity or straddle the 2 leaves? I'm sure a couple of drawings would answer all these questions but I don't seem to be able to find any!