The NOA for this CertainTeed asphalt shingle is clear on the type of flashings that can be used on this Chimney. Chimneys shall be flashed with a two-piece base and cap flashing to allow for differential movement. Apply shingles up to the front edge of the chimney before any flashings are installed. Bend the base flashing so that the lower section extends at a minimum of 4 inches over the shingles and the upper section extends a minimum of 12 inches up the vertical face of the chimney. Use metal step flashing for the sides of the chimney, positioning the units in the same manner as flashing on a vertical side wall. Attached are some pictures of the final product that appear to have passed by the building inspector. What do you call this contraption?
Continuous flashing or apron flashing. Many types and brands on the market.
I would call it a goobered up mess.
As would I…
Thanks. But the NOA, which refers to RAS 115, specifically says to use a two-piece base and cap flashing to allow for differential movement…positioning the units in the same manner as flashing on a vertical side wall.
RAS 115 does makes reference to RAS 111 which describes the counterflashing though.
RAS 111 says counterflashing must not be continuous across moving wall joints. And since RAS 111 negates the use of this type of flashing when it says “it must not be continuous.” Then this flashing is not compliant with the NOA. Wouldn’t you agree?
There are no moving wall joints (expansion joints) on that stucco covered chimney.
Check with the AHJ in your jurisdiction, they’ll tell you if they allow the product for that application.
What are NOA and RAS?
Notice Of Acceptance
Roofing Application Standard.
NOA Florida Product Approvals are set by the State for all construction trades. They are products that the State approves for use in all areas of Florida , including the Hurricane Zones. … Miami-Dade Notice of Acceptance (NOA) are set forth by Miami-Dade county for all construction trades.
RAS roofing application standard has been developed to provide a responsive method of complying with the require- ments of Chapters 15 & 16 (High-Veloc- ity Hurricane Zones) of the Florida Building Code.
When contractors apply for a permit here in Florida they must provide specs on the materials they are going to install. These materials have to have a NOA and must be installed according to guidelines which are written on both documents.
There are several composition shingle installation defects.
A: Shingle chimney clearance. All sides.
B: Lack of step flashing.
C: Flashing miter detail.
D: Lack of cricket.
E: Foot traffic mastic smears.
F: Poor workmanship.
Roof decks move independently of chimneys and require decking clearance.
That flashing will not independently move as the roof deck moves due to the shingles are sealed to the flashing. The mastic prevents it.
Properly installed Step, Headwall, Apron & Counter Flashing on chimneys breaks that union.
Aaaaah, thanks Angelo!