The siding I'm using for the garage, gable ends, and shed dormer is 1x6 T&G cedar. It is rough on one side for exterior use, and smooth on the other for interior use. I'll be using it in the ceiling for the great room and loft as well. I got this particular siding from Buffalo Lumber, and I'm very pleased with it. You won't find it anywhere else for a lower price, and their service was top-notch. I highly recommend them.