Saundra, Rob is correct bsc.ca.gov is an excellent start. They have the new CALgreen code in pdf format available. But your post has me a bit confused because you are asking about retrofits, which would imply an existing building but then you go on to note "Title 24 New Construction". The building codes cover any new construction, be it a totally new building or a remodel or addition to an existing building. However, if you aren't doing any remodeling, you generally aren't required to make any changes (federal handicap accessibility laws are the exception). I hope this helps.
Architect, AIA and Certified Access Specialist (CASp), CASI
530 863 3849
Nov 29, 2010