Build a tin roof room

• 1). Raise the floor and wall system of the room to be added. This will follow general principles of building a foundation with decking and evenly-spaced, upright studs to anchor the board panels that will serve as the interior walls. Exterior walls should be matched to whatever siding the existing structure uses.
  
  
• 2). Build a flat-roof system by topping the wall system with a horizontally placed outer crossbeam. Once that piece is installed along the perimeter, run joists from one side of the roof system to the other. This will provide the skeletal framework that will be a foundation for the ceiling.
  
  
• 3). Nail down plyboard panels to complete the ceiling, making sure the nail points are approximately 12 inches apart, to insure maximum stability. This is important because the structure's integrity may be challenged by inclement weather and high winds.
  
  
• 4). Lay down roofing paper on the exterior side of the plyboard panels and nail it in place with roofing nails. Make sure to overlap each strip of the roofing paper with the layer that precedes it. This increases the weatherproofing effects of the material.
  
  
• 5). Place the prefabricated sheets of tin in place and nail them in with roofing nails. These nail points should be about 12 inches, as with the roofing paper, to anchor the tin to the roof system as firmly as possible. As a final step in weather proofing, put silicone caulking on each of the nail points to decrease the likelihood of leaks.