Garage construction for room in attic

I am building a new small garage that will be attached to the walkout level of my place with the roof reaching to the second floor. I would like to be able to make the attic an extra room that can be accessed from the second floor and would like some advice on how to build it. What style of roof would be best to give the most room? I was thinking I could use wood I beams for the ceiling joists to give it more support but am now sure what to do about the roof. It can't be too much of a pitch because the roofline must tie into the existing roof

If you made the new garage larger than the adjacent foot print of the house then you could make the roof anyway that you wanted.

Tom

Show us some pictures of your house where the garage will be and we can give you some idears.

Remember there are all kinds of fire code issues with "occupied space" over a garage, and it will possibly also effect the wall between that new space and the house.

The doors and wall between the garage and the house must be fire-rated. The ceiling must also be fire-rated drywall. ANy bedroom needs two means of approved egress and daylight. SPecifics need to come from the local codes.

One way to get some headroom is a Mansard roof, but that may not mate up well with the existing rooflines. Some garages end up being as big or bigger than the main house.