Do I Need A Permit To Build A Closet . Nail or screw the end studs to side walls and to the top and base plates and rough in the door opening by nailing the studs to the top and bottom. Whenever you expand the house in any way or alter the house's envelope, you will need a permit. 29 Luxury WalkIn Closet Designs (Pictures) from www.homestratosphere.com Closets are built into homes as a matter or practice and convenience, not as a legal requirement. A permit ensures oversight of your contractor’s work (or yours). A permit will also help you avoid.