IRC R905.2.8.3 Sidewall flashing. Flashing against a vertical sidewall
shall be by the step-flashing method. The flashing shall be
a minimum of 4 inches (102 mm) high and 4 inches (102 mm)
wide. **At the end of the vertical sidewall the step **
**flashing shall be turned out in a manner that **
**directs water away from the wall and **
onto the roof and/or gutter.
IRC R703.1 General. Exterior walls shall provide the building
with a weather-resistant exterior wall envelope. The exterior
wall envelope shall include flashing as described in Section
R703.8. The exterior wall envelope shall be designed and
constructed in a manner that prevents the accumulation of
water within the wall assembly by providing a water-resistant
barrier behind the exterior veneer as required by Section
R703.2. and a means of draining water that enters the assembly
to the exterior.
IRC R703.8 Flashing. Approved corrosion-resistant flashing shall
be applied shingle-fashion in such a manner to prevent entry of
water into the wall cavity or penetration of water to the building
structural framing components. The flashing shall extend to the
surface of the exterior wall finish. Approved corrosion-resistant
flashings shall be installed at all of the following locations:
- Exterior window and door openings. Flashing at exterior
window and door openings shall extend to the surface of
the exterior wall finish or to the water-resistive barrier
for subsequent drainage. - At the intersection of chimneys or other masonry construction
with frame or stucco walls, with projecting lips
on both sides under stucco copings. - Under and at the ends of masonry, wood or metal copings
and sills. - Continuously above all projecting wood trim.
- Where exterior porches, decks or stairs attach to a wall or
floor assembly of wood-frame construction. - At wall and roof intersections.
- At built-in gutters**.**
IRC Commentary:
The code requires that all points subject to the entry of
moisture be appropriately flashed. Roof and wall intersections
and parapets create significant challenges,
as do exterior wall openings exposed to the weather.
Where wind-driven rain is expected, the concerns are
even greater. Self-adhered flashing is required to comply
with AAMA 711. Although the code identifies a
number of locations where flashing is specifically required,
the entire exterior envelope must be weather
tight to protect the interior from weather. Therefore,
any location on the exterior envelope that provides a
route for the admission of water or moisture into the
**building must be properly protected. **Commentary Figure
R703.8 illustrates examples of flashing.