A solid, watertight roof is absolutely essential to your home, but the asphalt shingles that protect your roof from the elements don't last forever. The best shingles will last up to fifteen years, after which they must be replaced. With the right tools, workers, material, and cooperative weather, the project can be completed in a few days. But carefully consider the condition, location and pitch of your roof before deciding to do this project, which presents serious safety hazards to the do-it-yourselfer.

Firstly, If there is more than one layer of old shingles, or if the single layer is extensively warped or damaged, tear off the old layer of shingles and sheathing and dispose of them properly. Start at the top ridge and work your way down, removing all the old nails. Attend to any damage to the roof boards underneath, replacing any warped, rotted or damaged wood

Secondly, Before laying down shingles, you need to protect the roof with sheathing. Roll out a single layer of roofing felt or tar paper, which serves as a moisture barrier. Begin this layer at the bottom of the roof and add it in horizontal rows, with a slight overlap to prevent leaks. Instead of laying down the entire layer of sheathing at once, lay it gradually above each finished row of shingles. Attach the sheathing with galvanized nails. Use a double layer along the top ridge line.

Thirdly, Add a sheet of thin metal flashing to places where sections of roof join (“valleys”), around vents and chimneys and around other obstructions. Install a drip edge at the bottom edge of the roof to protect the fascia and wooden structure underneath. Use tin snips to cut the metal into the appropriate shapes and sizes.

Next, Starting at the bottom of the roof, lay down