My layout has been in the (double) garage for 15 years, so the answer to the original question is a definite 'yes'. I'm probably doing lots of things wrong, as there is minimal insulation, the doors are not draft proof or water tight round the edges and I once had a small stream running through it when our neighbour's guttering collapsed in a storm. I also have hot and cold running creatures in the garage (+ a grass snake once) and they invariably leave evidence of their visits, particularly the mice, so I wash my hands after each modelling or play session. Despite all this, I have only come across two problems and they both relate to Superquick card buildings. The roof of the good shed warped after about 5 years, and the sellotape I had used to stick some windows in place also gave up, so all windows are now stuck in place with evostik. Metcalfe models, that tend to have two pieces of card laminated together for the walls, seem very robust and don't mind the damp in the garage. My locos don't seem to have suffered either, with the oldest ones still running as well as when I first got them.