1. The average lifespan of a roof is about 20-25 years, depending on the type of roof and the climate in which it is located.
2. The most common types of roofing materials are asphalt shingles, metal, wood shingles and shakes, clay and concrete tiles, and rubber.
3. Asphalt shingles are the most popular type of roofing material in the United States, due to their low cost and wide availability.
4. Metal roofs are highly durable and can last 50 years or more with proper maintenance. They are also resistant to wind, fire, and rot, and are energy-efficient.
5. Wood shingles and shakes are made from cedar, redwood, or pine, and can give a home a natural, rustic look. They are susceptible to rot, however, and may not be suitable for all climates.
6. Clay and concrete tiles are durable and long-lasting, with a lifespan of 50 years or more. They are also resistant to wind, fire, and rot, but are heavy and may require additional support for the roof structure.
7. Rubber roofing is made from recycled rubber and is highly durable, with a lifespan of 50 years or more. It is also easy to install and requires little maintenance.
8. The slope or pitch of a roof is the angle at which it sits on a house, and is typically measured in inches of rise per foot of run. A roof with a pitch of 4/12 or greater is considered steep, while a roof with a pitch of 2/12 or less is considered flat.
9. The shape of a roof can affect its lifespan and performance. Gable roofs, which have two sloping sides that meet at a peak, are common on homes, but can be prone to wind damage. Hip roofs, which have four sloping sides that meet at a ridge, are more stable and wind-resistant.
10. The underlayment of a roof is a layer of material that is installed under the roofing material to protect the roof deck and provide an additional layer of waterproofing. Common types of underlayment include asphalt-saturated felt, rubberized asphalt, and synthetic materials.
11. The flashing on a roof is a strip of metal or other material that is used to seal around roof penetrations such as vents, chimneys, and skylights. Flashing is important for preventing water leaks and protecting the roof structure.
12. The eaves of a roof are the lower edges that extend beyond the walls of the house. Eaves can be open or closed, and can be protected by a fascia board, soffit, or both.
13. The gutter system on a roof is used to collect and redirect rainwater away from the house. Gutters are typically made of metal, vinyl, or plastic, and are installed along the eaves of the roof.
14. The ventilation of a roof is important for preventing moisture buildup and prolonging the life of the roof. Ventilation can be achieved through the use of attic vents, soffit vents, and ridge vents.
15. The attic is the space between the ceiling of a home and the roof and is used for storage or as additional living space. Proper insulation and ventilation of the attic is important for the energy efficiency and comfort of a home.
16. A roof leak can be caused by a variety of factors, including damaged or missing shingles, flashing, or underlayment; clogged gutters or downspouts; or a failure in the roof deck or structure.

It is important to note that replacing a roof can be a dangerous and complex task. If you are not comfortable or confident in your ability to complete the replacement, it is recommended that you hire a professional roofing contractor. A professional roofing contractor will have the expertise and experience to replace the roof correctly and ensure that it is properly sealed and protected against future damage. They will also have the proper safety equipment and training to complete the job safely.