ASHRAE 1985 Handbook - Fundamentals, and the Manual of Built-up
Roof Systems by Griffin. Where data reported by insulation
manufacturers differs from that shown in handbooks, appropriate
justification and explanation should be obtained. Where the
thermal resistance declines with age, the aged values should be
Tapered Insulation. Where the roof deck is flat or
level, one reasonable means available for providing adequate roof
slope for drainage purposes is by using the insulation; tapered
factory fabricated insulation may be used for this purpose.
Manufacturers of several types of board insulation provide a
variety of tapers. Where tapered insulation is to be used,
careful detailing and dimensioning is necessary in order to
ensure that the proper slope and positive drainage are achieved.
The use of tapered insulation should be limited to reroofing of
existing low slope roof buildings.
Application Criteria. It is extremely important that
the type or types of insulation to be used are appropriate for
the roof assembly. Refer to other sections in this handbook for
specific criteria with each type of roof deck and/or roof
membrane. Carefully read and evaluate the detailed application
criteria and limitations on use for several major manufacturers
of the type of insulation to be utilized or permitted along with
other sections of this handbook, in order to eliminate any
Specific provisions should be set forth for the
insulation manufacturer and contractor to meet to set up
requirements regarding storage and installation of insulation.
The insulation must be kept dry, both when stored on the job site
and when installed on the roof.
Waterproof covering over stored
insulation is essential, as is elevating the insulation so that
ground water cannot enter. Require that stored material be
adequately secured from blowing away. Insulation must be covered
at the completion of each day's work with completed roofing.
Means for securing the roof insulation to the roof deck
to resist displacement, such as adhesives and/or corrosive
resistant mechanical fasteners, which are compatible with the
materials used, should be specified. Refer to Section 12.