Pcinspector1 said:
ICE, no requirement to install felt between asphalt shingles that I'm aware of. Felt required on the sheeting only. Felt also gives a little weather protection if it was to rain which would protect the sheeting if it's overlapped properly.
pc1
Pc1,
I have heard reasons for and against installing underlayment. Manufactures reps. aren't consistent. Some have said that underlayment is always required and some not. When asked if a lack of underlayment could void a warranty, they reply that it depends on the subject defect. I have seen manufactures installation guidelines that show a method called "nesting shingles" if underlayment is to be omitted, with the proviso that local codes may not allow it.
Those same manufacturers produce expensive underlayment that is required, per their product warranty, on high end shingles.
2009IRC:
Section R905 REQUIREMNETS FOR ROOF COVERINGS.
R905.1 ROOF COVERING APPLICATION.
Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturers installation instructions.
R905.2 ASPHALT SHINGLES.
The installation of asphalt shingles shall comply with the provisions of this section.
R905.2.2 SLOPE
For roof slopes trom 2" up to 4" pitch, double underlayment is req in accordance with Section R 905.2.7.
R905.2.3 UNDERLAYMENT.
Unless otherwise noted,
required underlayment shall conform to ASTM........
R905.2.7 UNDERLAYMENT APPLICATION.
For roof slopes 2" up to 4" pitch, underlayment shall be two layers applied in the following manner........
For roof slopes of 4" pitch and up, underlayment shall be one layer applied in the following manner........
SECTION R907 REROOFING.
R907.1 GENERAL.
Materials and methods of application used in
re-covering or replacing an existing roof covering shall comply with the requirements of Chapter 9.
Definitions:
Roof recover. The process of installing an additional
roof covering over a prepared existing roof covering without removing the existing roof covering.
A "recover" is the installation of a "roof covering". Apparently, a roof covering is required to have underlayment. Where is the loophole?