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Roofing/Roof underlayment


We live in Phoenix, AZ and have a house with a tiled roof.  Approx. how long does the paper underneath it last?  Our research shows about 15-20 years.  Thanks

Dave and Patty,
I'm assuming that you are referring to the underlayment, which is likely a 30# asphalt underlayment. You are correct that this should last 15-20 years on average. This is a very broad question and there are any number of instances where that span will increase or decrease. If the underlayment is not exposed to UV or water, it may last much longer, and the opposite is true.
It is important to note that tile roofs are a water-shedding roof. Meaning that they are not waterproof, but keep the water out by providing slope that allows water to naturally follow the path of least-resistance and evacuate from the roof. If there is a location where wind is able to blow water under the tiles, the underlayment is then the method to keep the water out of the house. The underlayment is lapped, with multiple fastener penetrations (which are avenues for moisture penetration).
There are other underlayment products which may last longer and provide better protection for the roof, such as self-adhered underlayment or synthetic, your roofing contractor should be able to provide pricing for these products and indicate the pro's and con's of each.
Best of luck to you,


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Aaron Nelson


All types of questions with regard to roofing, waterproofing and sheet metal. This includes commercial and residential buildings, along with the various aspects of the construction means and methods, ventilation, steep-slope or low-slope, code requirements, installation errors and other such problems


I started in roofing fabricating and installing sheet metal flashings out of high school for a large commercial contractor. I worked for the same contractor in the office estimating and project managing commercial project for 10 years. I left the construction side of roofing and now work as a roof consultant, which I have been doing for 8-years.

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I am a Registered Roof Consultant (RRC) and a Registered Roof Observer (RRO) through RCI, Inc. RCI is a international group of building envelope professionals. I am an approved instructor for RCI educational programs.

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