Building Design and Construction Handbook - Merritt - Ventech!

12.18 SECTION TWELVE
In addition to these resources, designers would find it helpful to establish a
working relationship with a professional roofing contractor. Many contractors are
willing to spend some time with designers. This can be particularly helpful if the
designer is working on a project that has some unusual aspect, or if a material or
system is being contemplated with which the designer is not familiar. For more
extensive input, utilization of a professional roofing consultant may be advantageous.
12.7 BUILDING OWNERS’ REQUIREMENTS
It is important for roof designers to determine if the building owner has any specific
requirements, such as type of materials; what the building owner’s expectations are
regarding the roof’s longevity; and to what extent the owner is committed to maintenance.
If the owner is unwilling to allocate adequate funds for maintenance, a
conservative durable system should be selected.
Also, designers should determine how detrimental leakage or a roof flow-off
would be. For most buildings, these events are unpleasant but generally manageable.
But, if the roof is over very expensive electronic equipment, or a critical facility
such as a hospital, a conservative roof design may well be appropriate. It is also
desirable to determine if the owner’s insurer has specific requirements for the roof
system.
Contract documents should be carefully designed and administered. A good
roof design should be complemented with comprehensive, unambiguous specifications
and drawings, so that the design intent is clearly communicated to the
contractor.
12.8 BUILDING-CODE PROVISIONS FOR ROOFS
Designers should be aware of building-code requirements affecting design of the
roof. Model building codes and many state and local codes have provisions related
to roof systems (for new construction, as well as reroofing).
Fire and wind resistance, material standards, storm water drainage, structural
loading, and energy efficiency are some of the many objectives of building codes
that are common to roof design. Many local jurisdictions have such requirements
for residential and/or commercial construction.
12.9 EFFECTS OF CLIMATE
The climate in the region where the roof will be constructed often plays a key role
in design of the roof system. Climate considerations should include the type of
weather that will likely be encountered during application, as well as the climatic
conditions that follow. For example, if the roof is to be constructed during cold
weather or in a location that experiences frequent rains, selection of materials and