Because of the wide variety of panel profiles and design features, GALVALUME SSR systems should be installed according to SSR panel manufacturers' construction practices and details. SMACNA (Sheet Metal and Air Conditioning Contractors National Association) Architectural Sheet Metal Manual specifications should be used as a guide and basis for details wherever applicable.
Structural GALVALUME SSR systems are typically installed directly on purlins on new roofs. Concealed clips are attached to the purlins and the GALVALUME SSR panels and clips are joined together by forming, crimping or snapping at the seams. Clips are designed with slots and tabs to accommodate thermal expansion and contraction.
Fiberglass blanket insulation is most commonly used on new structural GALVALUME SSR systems to reduce energy costs and to provide noise dampening. The insulation blankets are installed directly under the panels and stretched over the supporting structural members. The underside (towards the inside of the building) of the insulation typically has a vapor retarder to prevent moisture penetration from inside the building and subsequent water condensation on the underside of the SSR panels. Vapor retarder closure systems and seams must be sealed correctly and all punctures, penetrations or holes in the vapor retarder must be repaired with tape. Foam insulation blocks are also generally used to separate the panels from the purlins to prevent thermal short circuiting.
Compatible accessories, flashings and gutters are available for structural GALVALUME SSR systems. Large equipment units are mounted on curbs which expand and contract with the roof and small openings are accommodated with flexible roof jacks. Gable, eave and parapet wall flashings are also used to lock out water and moisture. Other special components include walkways, ventilators, scuttles and gutters.
For retro-fit applications, structural GALVALUME SSR is installed on a sub-framing system which, in turn, is attached to the existing roof surface to provide a minimum 1/4:12 slope for the new roof. The structural members of most existing non-metallic roofs can support the lightweight SSR panels and structural steel sub-framing system, which weigh about 2 to 5 lbs/sq.ft. (9.8 to 24.4 kg/sq. m.). However, the existing roof structure should be analyzed to determine that it can support the anticipated loads. Insulation blankets can be installed on the sub-framing system the same as on new roofs or simply laid directly on the existing non-metallic roof surface. Ventilation of the cavity between the new roof and the old roof should be considered to avoid condensation. SSR panel manufacturers should be consulted for design and installation details of the sub-framing system for retro-fit applications.
Architectural GALVALUME SSR systems are typically installed on a metal or wood deck fastened to the roof structural system. Concealed clips are used to fix the panels to the deck. Spacing of clips and the number of fasteners per clip are specified by the SSR panel manufacturer. A layer of 30 pound felt paper, or equivalent, should be used to insulate the deck from the GALVALUME SSR panel. An insulation/waterproofing underlayment is particularly important when installing a GALVALUME SSR system on chemically treated wood deck.
Because architectural panels are used for aesthetic purposes, care should be exercised in handling and installing such panels. Painted panels need to be protected from damage. Scratching of the paint can be caused by walking on the panels or using improper tools during installation. Some manufacturers supply painted panels with a strippable clear plastic film to protect the surface during installation. Such films should be removed within one week after the panels are installed.
Unpainted GALVALUME architectural SSR panels should also be handled carefully during installation.
Gloves should be sued to avoid hand marking and foot traffic should be avoided to eliminate shoe scuffing and marking. Panel manufacturers should be consulted when unpainted GALVALUME SSR architectural panels are to be used. Careful handling of such panels is required from manufacture to installation.
Other design, installation and maintenance guidelines for GALVALUME SSR systems are:
Standing water conditions should be avoided by providing for drainage of water from roofing panels and around roof penetrations. SSR panel manufacturers can provide installation details.
Cascading water from higher roof elevations onto lower roof panels can cause erosion of the paint and metal coating on GALVALUME SSR. Panel manufacturers should be consulted for handling expected large volumes of rainwater draining from GALVALUME SSR.
Snow and Ice:
Special design considerations are required in heavy snow areas to accommodate additional snow loads, sliding snow off the roof and ice damming at eaves. Design guidelines for the roof system should be discussed with SSR panel manufacturers.
Copper, lead and unprotected steel should not be used with GALVALUME SSR panels. Likewise, GALVALUME SSR panels should not come in direct contact with wet and/or weather treated wood or uncured concrete. Wood retains moisture and weather treatments contain corrosive chemicals that can shorten the life of a panel in direct contact. Uncured concrete is very alkaline and may attack the aluminum-zinc coating. Compatible, long-life flashing such as GALVALUME and aluminum sheet should be used.
Compatible fasteners with long-term corrosion resistance should be used for GALVALUME SSR systems. Recommendations for suitable fasteners are available from panel and fastener manufacturers.
Good quality sealants should be used that provide long- term resiliency and flexibility necessary to seal the joints for the life of the GALVALUME SSR panel. Sealants with acetic acid should be avoided. Contact SSR panel or sealant manufacturers for specific recommendations.
Air Conditioner Drains:
Drain water from air conditioners contains dissolved copper from the condensation coils. Discharge of this drain water from roof-top units onto GALVALUME SSR panels can cause rapid corrosion of the aluminum-zinc coating. Condensate from air conditioners should be discharged through a plastic pipe extended at least to the rain gutter but preferable to the ground.
After erection, GALVALUME SSR panels should be swept to remove dirt and debris such as unused fasteners, metal filings and drillings, pop-rivet stems and pieces of flashing. For example, metal drillings can rust quickly and easily be mistaken for rusting of the GALVALUME sheet.