15lb or 30lb felt ?
In order to achieve fire-resistant ratings
(Class A or C), an underlayment must be used regardless of the
type of shingle being installed.
A minimum of 2 layers of felt is required
for roofs with slopes less than 4/12. In such cases, the
application must meet the requirements for low slope roofs.
Alternatives for 2 layers would be 1 layer ice and water shield.
The difference between the two :
We prefer the heavier felt for a few
reasons. One, we prefer to provide a more durable temporary water
barrier while in renovations. Two, the 30 lb felt wont tear out
while walking on steep roofs. Three, the paper lays evenly
reducing wrinkles in the roof system.
30 ASTM --
Features a premium quality TAMKO organic felt that is
saturated with asphalt. Accepted for use as an
underlayment felt to be applied over the deck prior to the
installation of TAMKO asphalt shingles. ASTM D-226, Type
II. 72'x36" 216 sq. ft. per roll
PLAIN FELT 2SQ/RL
Other felt products by Tamko
and Metal Under layment and or Ice and Water shield
us ? Same product different names but same effect, overall
the best secondary solution for high water areas, flashing
details and roof penetrations. As seen in the photo below.
Ice and Water Shield can add added protection to the life
cycle of the roof. Also can be used for low sloped roofs.