The price of a new roof system varies widely, depending on such things as the materials selected, contractor doing the work, home or building, location of the home or building, local labor rates and time of year. To get a good idea of price for your roof system, get three or four proposals from reputable contractors in your area. Keep in mind that price is only one factor, and it must be balanced with the quality of the materials and workmanship.

For each roofing material, there are different grades and corresponding prices. There also are a variety of styles and shapes. You need to look at the full product range and make a choice based on your budget and needs.

Within the roofing profession, there are different levels of expertise and craftsmanship.

You have two basic options: You can choose a complete replacement of the roof system, involving a tear-off of your existing roof system, or re-cover the existing roof system, involving only the installation of a new roof system. If you've already had one re-cover installed on your original roof system, check with a professional roofing contractor. In many instances, building code requirements allow no more than one roof system re-cover before a complete replacement is necessary.

Most new roof systems are designed to provide useful service for about 20 years. Some roof system types, such as slate, clay tile and certain metal (e.g., copper) systems, can last longer.

Actual roof system life span is determined by a number of factors, including local climatic and environmental conditions, proper building and roof system design, material quality and suitability, proper application and adequate roof maintenance.

Roofing product manufacturers offer a variety of warranties on their products. Take a close look at those warranties to see what responsibilities and financial obligations manufacturers will assume if their products fail to reach their expected lives.

Not necessarily. Leaks can result from flashings that have come loose or a section of the roof system being damaged. A complete roof system failure, however, generally is irreversible and a result of improper installation or choice of materials or the roof system installation is inappropriate for the home or building.

Use a mild solution of chlorine bleach and water or mild detergent gently applied with a sponge or hand-held sprayer and rinse thoroughly. Do not use a power washer or high concentrations of bleach, and do not scrub the shingle surface.