Saw the first of Mike Holmes' new season of home repairs. He fixed an old couples' duplex which had an odd roof configuration that perpetually leaked. He extended the roof up into a peak as a normal house would use. However, the houses had an 8" concrete block firewall between them. When he extended to roof framing, the firewall had to be extended up to the underside of the new roof.
Personally, I would have extended the block wall with more blocks as it would be an excellent firewall but Holmes, who normally has distaste for the minimum code requirements and tends to over build most things he works on, extended the firewall with a wood frame and drywall. I know it is legal, (in the past when these homes were originally built, it was not legal) to construct a firewall out of drywall but this is the minimum code requirement.
I see he is now lowering his supposed standards down to the minimum code requirement.