Felt Paper

• It is important when roofing a home with asphalt shingles to first lay down a layer of felt paper. This will help ensure the roof will not leak during a rain storm. Felt paper comes in rolls about 3 feet wide. Start at a bottom corner of the roof and unroll across the roof. Tack down using a staple gun. The felt should come right to the edge of the roof. Repeat laying a second row of felt, overlapping the first layer by 2 inches. Be sure that the felt is tight and there are no bubbles or wrinkles.
  
  

Drip Edges

• Drip edges are made of rust-resistant metal. They are an L-shape and are designed to keep water from getting under the felt paper. After you install the felt paper you should install the drip edges over the top along the edges of the roof. Lay one leg of the L-shaped drip edge over the felt paper and the other leg resting on the edge of the roof. Attach using corrosion-resistant nails. Go around the entire roof this way. The drip edges should overlap about an inch where they meet---you do not want a seam where water can enter.
  
  

Starter Strips

• The first row of shingles actually isn't the first row. The actual first row is called a starter strip. Three-tab shingles have seams designed to lock together with adjacent shingles to form one continuous strip. If you lay down the first row without a starter strip there will be seams due to the design of the shingle where water can get in. Take a regular, three-tab shingle and cut off the bottom 5 inches. You should now have about 7 inches to work with. Install these shingles at the bottom edge of the roof using roofing nails, overhanging the drip edge by about 1 inch. It is important that you do not apply the shingles so they are flush with the edge of the roof as water will pull back under the shingle and enter the roof.
  
  

Flashing

• Flashings are used where shingles meet something other than roofing material, like where a chimney comes up through the roof. It is critical that the shingles butt up against the chimney and lock with the flashing to keep water from penetrating. It can be tricky but it is critical that you get it right or else you will have leaks. It is important that flashings be made from corrosion-resistant metal, like lead, which can be soldered to ensure a complete seal.