You could remove the opener and permanently seal off the door on the
inside, then put in a false wall with insulation and a vapor barrier
and then sheetrock it just like toe other walls, after you insulate
them, On the outside it will still be the original door, and if you
sell you can tell the buyer that the false wall can be removed and the
space converted back to a garage. You will loose a few inches due to
that new wall being slightly thicker due to the original door being
thicker than siding would have been, but if you are hurting for a few
inches, then your garage must be awfully tiny. Bggest problem I can
think of is electric outlets on the new false wall if you want to put
something against that wall. Any wiring needs to be code, in case of
a fire or other disaster. You don't say if you will try to get a
permit or not.


A nice way to do this is to leave 6 feet or so between the wall and the door
so it can still be opened. The space can be used as storage. Locally the
city picks on people who convert their garage and won't let them park in
their driveway any more saying it is not a driveway but part of their yard
since they do not have a garage. Leaving the door there and working would
help fool everyone into thinking there still is a garage.