01 May 1999
12-1. OVERVIEW OF ROOF MAINTENANCE. All roofing systems require maintenance. While this EI
is primarily intended for the selection and design of roofing systems, maintenance must be kept in mind
since even the best roofing system will fail prematurely if not maintained. The primary intent of this
Chapter is to enumerate those things a designer can do to improve the performance and longevity of
roofing systems. As mentioned in Chapter 11, good roof design anticipates maintenance, reroofing or re-
covering. Providing positive slope within the structure itself assures the roof will drain properly.
Adequate clearance is needed so that these functions can be performed. Counterflashings should be
high enough to accommodate additional roof insulation.
(1) Separation of Rooftop Units. Roof penetrations should be spaced a minimum of 305 mm (12
in.) apart (see figure 12-1). If this minimum spacing is impossible, then penetrations should be clustered
and brought through a curbed opening (figure 12-2).
(2) Removable Counterflashing. Providing two-piece counterflashings permits removal of the
snap-in piece so that the roof may be more easily reflashed (figure 12-3).
(3) Eliminate Pitch Pans. Use watertight sheet metal rain collars instead of pitch pans to reduce
the need to periodically refill the pans to assure watertightness (figure 12-4).
(4) Anticipate Movement. Where differential movement is expected between roof and wall, use
nonwall-supported base flashing designs (figure 12-5).
(5) Design Coping System to Shed Water. Slope all copings to shed water back onto the roof.
Provide a watertight membrane at least under the coping joints and preferably under the entire coping
(6) Avoid Metal Flashings Embedded Within Roof Membrane. Avoid embedded metal such as
illustrated in figure 12-7a. Use raised metal such as illustrated in figure 12-7b.
(7) Operations and Maintenance Manual. The Operations and Maintenance Manual given to the
owner should contain copies of any roof warranty with attention drawn to occupant obligations and
notification requirements. Accurate and comprehensive records such as those used in the ROOFER
program are recommended. Any requirements for special tools or materials should be noted as well as
references, instructions, or training needed. Excellent references are available on maintenance of each
type of roof system discussed in this EI.
b. Inspection and Maintenance.
(1) Roof Surveys. Visual inspection should follow checklists similar to those provided in the RIEI
Roof Maintenance Manual, the NRCA/ARMA Manual of Roof Maintenance and Repair, or when
applicable, used in the ROOFER program. Moisture surveys are recommended at 3-5 year intervals on
insulated roof systems. Such surveys are required to properly analyze insulated low-slope roofs using