Tiger seal some carpet to the walls where the door would potentially hit
Yep great idea BM, ...although instead of carpet I'd use these soft floor interlocking tiles that you can get from Halfords/Aldi for around a tenner.
Link: http://www.halfords.com/workshop-tools/garage-equipment/garage-essentials/rolson-6-piece-floor-mat-set-120-x-180cm