A garret or an unfinished attic can be made into just exactly the kind of space young folks are looking for.
Just last week I was working on a house where the just-turned-teen-age girl of the family had staked out her claim on the two attic rooms. She had had it with sharing the second floor with her younger brother and wanted a private suite for herself and her friends. The two small rooms, one even equipped with its own sink, offered an ideal arrangement for her, a bedroom in the room with the sink and a parlor in the larger room.
It was easy to accomplish; the walls were already finished and the only important changed was to air condition the space. One window model in each room easily did the trick. Shutters at the window, the small hall that connected them, track-lighting that could be angled to take advantage of the slanting ceiling, low-down pillow furniture for the parlor, a tall brass bed for the bedroom, and it was ready to move into.
If your garret is unfinished, you could leave the exposed beams intact, as part of the structure, and simply insulate the places between the beams, as well as the vertical wall sections.
In a home where the top floor was all unfinished garret, I designed a haven for two-boys, one 11 and the other 9. Their only qualification, initiated, no doubt, by a sensible mother, was that the place be durable enought to withstand a lot of abuse without causing concern for maintenance. One boy, a budding artist, asked for a drafting table, the younger son simply wanted a cozy place to curl up and read a book or listen to music.
The wooded structure of the attic was attractive even in its unfinished state. The beams and posts were clear pine, with a rich grain that became more evident and attractive when a pale stain and finish were applied to the wood. Insulation and dry-wall were added to the vertical surfaces. The places between the beams' on the ceiling were painted in a heavy sand finish rather than a flat paint to provide texture, more accoustical privacy and easier maintenance.
The floor was covered in a typical commercial carpet, the kind that is ordinarily used in offices. Its nylon fibre, in a medium gray, closely tufted loop construction, makes an easy-to-care-for surface that also warms up the space in winter and keeps the sound down.
Factory lights were used for general illumination, and clamp-on work and bed lamps provide additional boosts for work and reading when needed. The two small windows were covered with unfinished shutters, matching the posts almost exactly.
To make the space work for the two guys involved, I built two beds intod the long wall at the head of the space, using unfinished wood for the frames and mounting these over large and spacious drawers that roll out to provide extra beds for sleep-over friends. The bedcovers are made of terrycloth towelling, one in chrome yellow and the other in orange-red, with elasticized edges for easier contour fit. Bright pillows of the same fabric are mixed with bed pillows, covered in bright blue sheeting with a white clouds design to match the bed linens.
A stood painted orange-red sits in front of the natural wood drafting table, which also doubles as a desk for homework for the older boy. A leather-color vinyl-covered "snake" - simply a 16-foot tube filled with polyster chips - becomes a whole seating environment for a reader or a whole party, depending on the occasion.