It’s a question we are asked all the time: How long my roof is going to last? Not all roofs are created equal; your roof’s material plays the major role. Metal or slate roof lasts 50+ years; in many cases, the roof lasts as long as the home itself, and that can be 100 years or more.

Since the question mentioned lifespan of an “average” roof, we’re going to assume that it’s a typical asphalt shingles roof, which is currently the most popular type of residential roof material.

Shingles are made in different weights. The heavier the weight of the shingle, the longer it will last. The life expectancy of the shingles will be determined by the many factors that will all have a bearing on how long they will last.

How well the attic is ventilated will make a difference to the shingles life expectancy, the hotter the attic is the shorter the life of the shingle. The color of the shingle, light colors do not get as hot as black.

Most houses have a roof that has shingles that are worn out on the side that gets the most weather, while shingles on the sheltered side get less wear. The life expectancy of shingles is affected by both the pitch (slope) of the roof and the weather.

Hot summers and harsh winters will reduce the life of the shingle. Generally, shingles in cooler climates seem to last longer than those installed in the warmer climates. Studies have shown that the average lifespan for a 20-year shingle in Phoenix, Arizona is around 14 years. In Minneapolis, Minnesota the lifespan was 19.5 years. Based on our experience, we’d say that an average lifespan for shingles in the Chicago climate is about 20 years, give or take a few years.

Roofing manufacturers label and sell their shingles as twenty, twenty-five, or thirty-year shingles. This is the length of time the shingles would be expected to last in a perfect climate.

Twenty-year shingles do not usually last much longer than about fifteen years and may show signs of deterioration between ten and twelve years.

Twenty-five-year shingles have a useful life of about eighteen to twenty years.

Thirty-year shingles have about a twenty-five-year life expectancy.

Shingle manufacturers provide product warranties against manufacturing defects ranging from twenty (20) to forty (50) years and beyond. The warranties will cover defects such as thermal splitting, some cases of granule loss, cupping, and curling. It is very important that you ask for and receive a copy of the manufacturer’s written material warranty before making a decision on whose material you’d like to use.

Warranties are generally for materials only. Labor is rarely included so if your roof materials fail, you’ll have to pay a roofer to install the new shingles. Warranties almost never cover what are known as "incidental and consequential" damages resulting from material failure.

"Incidental and consequential" damages are those that occur to the interior of the building. If anything on the inside of the building gets damaged, you or your insurance company will have to pay for it. Warranties are also commonly prorated and non-transferable. This means that if you have twenty-year shingles and they fail after ten years, you’ll be reimbursed for half the cost of the materials. Non-transferable means that if you sell your house, the warranty will be voided.

Shingle manufacturers will not warrant their products against "Acts of God or Nature" such as hurricanes, hail storms, severe winds usually in excess of 50 mph, tornadoes, earthquakes, etc. Nor will shingle manufacturers honor their material warranty if the products are improperly installed, if there is improper roof ventilation, if there is equipment installation or structural changes after roof completion, or if there is heavy foot traffic on or over the roof.

For specific warranty information, ask your roofer to provide a sample warranty of the materials he installs. Needless to say, always choose an experienced, bonded, insured and honest roofing installer.