External door frame.

[neiloneil]

I have got a new timber frame to replace my Mum's old rotted one. I have not cut out the old one yet as I need advice on how to proceed.
The house was built in the early 1970s What should I expect to see when I remove the old frame, regarding damp proofing?
How should I prepare the opening to accept the new frame?

 

[^woody^]

You cut the frame out and fix the new one in, make good plaster and necessary and mastic around the outside. You don't do any damp proofing

You need to bed the cill on mortar