26 September 2006
All buildings over two stories must have a roof hatch or building-attached exterior ladder
for roof access. Roof hatches are recommended for all buildings over 280 m2 (3000
Flashing must be one of the following materials:
a. Prefinished aluminum at a minimum thickness of 0.813 mm (0.032 in.),
b. Aluminum at a minimum thickness of 0.813 mm (0.032 in.),
c. Copper at a minimum thickness of 454 g (16 ounces),
d. Stainless steel at a minimum thickness of 0.635 mm (0.025 in.),
e. Prefinished galvanized (G90) at a minimum thickness of 0.607 (0.0239 in.)
may be used in locations expecting significant physical abuse or a building
/roof life less than 15 years,
f. Lead coated copper 454 g (16 oz.) may be used at historical sites, and
g. Galvanized steel (G90) at a minimum thickness of 0.607 mm (0.0239 in.)
may be used for a building/roof life less than 10 years.
Snow and Ice Considerations.
Most steep roofs drain over their eaves. Some low slope roofs also drain to eaves, but
most drain internally. Over the eaves drainage in cold climates can be problematic if
snow and ice issues are not considered early in the design process. Consider design
contained in the CRREL report MP-01-5663, Minimizing the Adverse Effects of Snow
and Ice on Roofs.
Determine roof pressure zones in accordance with ASCE-7. Coordinate component
selection and required attachments in order to obtain the required wind resistance
Asphalt shingles provide versatile, low-cost steep slope roofing. To ensure a quality
consistent with other roofing systems the following requirements apply.
Asphalt shingles may not be used on slopes lower than 4:12 for new construction.