Roof slopes between 2 and 12 and up to 4 in 12 require double underlayment as detailed in table 905 1 1 2.
Irc 2015 roof underlayment.
The city of st.
See special installation requirements of manufacturer and irc.
The irc regulates work on one and two family dwellings and townhouses.
In areas where the average daily temperature in january is 25 f 4 c or less the metal valley flashing underlayment shall be solid cemented to the roofing underlayment for roof slopes under seven units vertical in 12 units horizontal 58 percent slope or self adhering polymer modified bitumen sheet.
For roof slopes from two units vertical in 12 units horizontal 17 percent slope and up to four units vertical in 12 units horizontal 33 percent slope underlayment shall be two layers applied in the following manner.
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The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
Peters has adopted the 2015 international residential code irc with amendments.
Last updated july 13 2020.
R905 3 minimum 3 in 12 for metal roof shingles see special installation requirements of manufacturer andirc.
Roofing underlayment or felt is usually required for the ul fire rating to apply since shingles are usually tested with underlayment.
The code requirements for re covering or replacing an existing roof covering can be found in irc section r908 reroofing.
The city made one amendment to irc chapter 9 sections r905 2 8 2 valleys.
The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.
In chapter 9 of the 2015 irc the underlayment requirements for steep slope roof coverings are included in three tables material types application and attachment requirements.
R806 5 unvented attic and unvented enclosed rafter assemblies.
Roofing underlayment or felt helps prevent unevenness in the roof sheathing from telegraphing through the shingles.
Fifteen pound or heavier felt underlayment is required by code in some areas.
Unvented attics and unvented enclosed roof framing assemblies created by ceilings that are applied directly to the underside of the roof framing members and structural roof sheathing applied directly to the top of the roof framing members rafters shall be permitted where all the following conditions are met.
This page references the 2018 international residential code.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.