TWM Roofing Owner

Roof Inspection Basics

Serving San Diego County with Roof Inspections & Escrow Bids!


Average Roof Life Southern CA.
• Tile Underlayment/Tar Paper = 25 to 30 years
• Asphalt Composition Shingles = 20 to 25 years
• Flat Roofs Residential = 10 to 15 years
• Flat Roofs Commercial = 15 to 20 years

Tile Roofs
The tile is primarily decorative and the underlayment / tar paper and the metal flashings are the primary components that keeps the water out. The life of the underlayment is 25 to 30 years, at which time it has deteriorated due to age and weather. In many cases, the original tile can be re-installed when the house is re-roofed with new underlayment. The code still allows one layer of underlayment, but all tile roofs should have 2 layers of underlayment. #30 ASTM or #40 are comparable in quality and cost. We are skeptical of all synthetic underlayments, due to a lack of successful, long-term history in the roofing industry. We know that a single layer of #30 or #40 is lasting 25 to 30 years. We are confident that two layers of high quality #30 or #40, with double flashings will be last 40 to 50 years.

Asphalt Shingles
Most properly installed asphalt shingle roofs from the 90’s or early 2000’s last an average of 20 to 25 years. Asphalt shingles are an extremely trouble free, low maintenance roof system WHEN properly installed. When asphalt shingles are not installed properly, it greatly reduces their life expectancy. With asphalt shingles, it’s usually not practical to remove a section of shingles and re-install or replace them to correct a problem like we can do with tile roofs. When asphalt shingle roofs leak at valleys or in the middle of the roof it is invariably due to improper installation and replacing the roof is often the solution. However, leaks at specific flashing details are often readily repairable, such as chimneys, skylights or pipe vents.

Back in the 70’s asphalt shingles were sold as 240# shingles with a 15-year warranty. These shingles lasted an average of 25 to 30 years or more. In the 80’s, asphalt shingle manufacturers began to escalate the warranty terms to 20, then 25, and 30 years. In the 90’s came 40 year shingles. Now, we have 50 year and LIFETIME warranty terms for asphalt shingles. In our opinion and experience, there is no such thing as a 50 year asphalt shingle roof. We think today’s 50-year / lifetime shingles will last 25 to 30 years. Time will tell.

Flat Roofs / Commercial
There are several types of flat roofs including torch membranes, tar & gravel and hot mop systems. The average life on residential applications for all these types is 10 to 15 years. We see some exceptions lasting to about 20 years but they are truly the exception. Commercial applications typically last 15 to 20 years and we do see a few exceptions lasting longer.

Please note that these averages are based on our hands on experience during the last 40 years and there are many variables that can affect the life of a roof. These timelines do not apply to poorly installed roofs. Many customers will experience roof leaks prior to the life expectancy timeline. It doesn’t matter if you have a 50 year shingle or Lifetime tile roof if it’s not properly experience.

How long will my roof last?
This is the most common question that every roofing contractor hears. The truth is that it largely depends on the owner’s objectives, budget, roof performance history and risk tolerance. The averages noted above provide a general guideline.

How do I know what condition my roof is in?
Getting a roof inspection from a licensed roofing contractor is the best way to determine the condition of the roof.

Additionally, here is some criteria that can help you assess the condition of your roof on your own.
• Tile or Asphalt Shingle roofs that have NOT leaked in the first 20 years often last about 30 years.
• Flat roofs that have NOT leaked in the first 10 years often last about 15 years.
• Knowing the roof history will also help determine how the roof is performing. If you are not the original owner ask previous owners and neighbors – especially with tract homes – roof issues are often consistent in a tract development.

Contact Us For A Roof Inspection

Name (required)


Email (required)

Relation To Property

Property Address

Request Type

Client Testimonials Guaranteed Authentic