Q. I need some additional living space for my family and for an apartment in which my parents will live someday. I was thinking of adding a room above my two-car garage. Is this a feasible project, and how should I design it?
A. It certainly is a feasible project to add a room or apartment over an existing garage. This is actually not uncommon now, as the poor economy has forced many elderly parents to move back in with their children. It is much less expensive to increase your living area this way as compared with adding a room on ground level. Also, often the lot is too small to add another room on the ground.
Before you start spending any money for an architect's designs or on contractors, check with your local zoning and building codes department. For example, there may be restrictions on how tall a building can be within a certain distance of the side lot line. Keep in mind that you will need stairs for access to the new room, which will increase the width of the existing garage.
Once you find you can build the new second-story room and not violate zoning, contact a construction engineer to determine whether your garage walls can support a second-story apartment. This may cost a little more than just relying on a contractor or architect, but the peace of mind is worth the extra expense.
Most attached garages are constructed with a framed or block wall, both of which are strong enough to support a second-story room above them. A detached garage requires more careful examination.
Plan the roof so its line is at the same angle as the house. If this is not possible, make it different enough to complement the existing house roof. This can be accomplished with the slope, roofing material or color. The last thing you want is to have it look as if you tried to match it but just missed it a little. The same is true for window size and style.