It is recommened that you inspect your roof for wear and tear every spring and fall. Begin in the attic. Look for signs of sagging, water damage and outside light showing through the roof. Then go outside and check for damaged or missing shingles, shingles granules (they look like grains of sand), mould and rot. If your inspection reveals minor damage and your roof is less than 15 years old, contact a licensed roofing contractor and get a repair estimate. If the damage is severe or your roof is more than 20 years old, consider replacing it.
Measure the approximate square footage of the ground floor of your home. Don't forget to include the measurements of the bathrooms, laundry room and closets.
Choose your roofing material. Factors to consider the include cost, appearance, durability and ease of installation. ThisOldHouse.com offers a guide to choosing the best roofing material for your home.
Decide whether or not you will replace the roof over your garage as well as the roof over your home if your garage is detached. Factors to consider include the contrast in the appearance of the new roof against the current garage roof and the condition of the garage roof.
Analyse the pros and cons of replacing the roof yourself versus hiring a licensed roofing contractor. The price of a new roof will be significantly lower without labour costs, but the peace of mind gained by hiring a professional is valuable.
Enter the information you have gathered into the ImproveNet.com Roofing Cost Estimator. This will yield a ballpark estimate for replacing your roof based on the average costs of roofing material and labour in your postcode.
Call at least three roofing contractors for estimates if you are planning to hire a contractor.