26 September 2006
Mechanically attach roof insulation for this type of roof deck, however, due to their
lightweight and flexibility, take care to prevent mechanical fasteners from backing out
enough to disengage the deck. Also, the design of the roof insulation must be tolerant
of a small degree of fastener back out. Two layers of insulation are required. The first
layer must be mechanically fastened. The second layer should be mechanically
attached or fully adhered in order to obtain the desired FM wind resistance
Structural Concrete Decks. Structural precast and poured-in-place
concrete roof decks are also commonly used on military projects. They are heavy and
are best suited to roof decks with relatively short spans. Minimize the use of
mechanical insulation fasteners to ensure the structural integrity of the deck. Due to the
inherent moisture in the concrete, take care during system selection and installation to
ensure that adequate bonding takes place between the roof system and the deck.
Wood-Plank and Structural Wood-Panel Decks. Wood-plank and
structural wood-panel decks were used in the past on many military facilities. Generally
this material should only be used on small buildings or in reroofing when the existing
material is in fair or better condition. Use of this material on new buildings must be
supported with strong arguments demonstrating that neither steel nor structural
concrete decks fulfill the specific functional requirements.
Cement-Wood Fiber Deck Panels. Cement-wood fiber deck panels
have limited utility due to concerns about moisture susceptibility. This type of deck shall
not be used for new construction.
Lightweight Insulating Concrete Decks. Lightweight insulating concrete
decks have limited utility due to concerns about ease of repair. Do not use this type of
roof deck for new construction.
Poured Gypsum Concrete Decks. Poured gypsum concrete decks have
limited utility due to difficulty in attaching membranes to the deck and difficulty in repair.
Do not use this type of roof deck for new construction.
Precast Gypsum Panel Decks. Precast gypsum panel roof decks have
been used on many military facilities. However, where membrane leaks have occurred,
these roof decks pose a safety hazard due to structural instability. Do not use this type
of roof deck for new construction.
Thermosetting Insulating Fills. Thermosetting insulating fills have
limited utility. Do not use this type of roof deck for new construction.
RIGID BOARD ROOF INSULATION.
Roof insulation is a very cost-effective means of reducing energy consumption.
Depending on climate and the type of membrane selected, the position of the insulation