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Roofing/Roofing underlayment


Florida, the correct way to install underlayment.What type should i use on a mobile home with a 3/12 slope

On a slope of 3/12 you will need to install a double layer of underlayment (two-layers) to comply with the building code. Here is a great link that will describe the proper installation method of underlayment. You can also look on the manufacturer's website of the underlayment for their specific instructions. You asked about what type to use - it really depends on the type of covering you are going to install. I'm assuming that shingles will be the roof covering - if that is true a double layer of 30# underlayment would be great! There are also synthetic underlayments, and lighter (15#) that can be used, however I would recommend traditional methods - thus the 30#.
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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.

RCI, Inc.

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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We have worked with many local school districts, insurance companies, HOA's, building management companies, and we have a national client with buildings located throughout the US.

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