How long does a roof last?
Just like most construction products, roofing material ages at different rates depending on numerous factors such as: the quality of the original roofing material, the skill of the installation crew, the level of maintenance, suitability of structure design, and so on. In general, wood roofs last around 18-25 years, composition roofs last anywhere from 15-30 years, and flat roofs about 10-25 years. Most roofing professionals feel that 20 years is an acceptable service life. Please keep in mind that manufactures warranties do not reflect the actual life expectancy you can expect from roofing materials.
How long does it normally take to replace a roof?
Generally a residential re-roof can be started and completed in a few days. Commercial projects can last for many days or weeks depending on the complexity and size of the building.