Installation Instructions

Building Design and Construction

In order to ensure the anticipated performance and longevity, protect metal panels from potentially corrosive situations and materials. When treated lumber will be in direct contact with metal panels or flash- ings please note the following: Galvanized steel is compatible with the CCA (Chromated Copper Arsenate) pressure-treated lumber that was predominantly used before 2004, except not with the older Penta treated lumber or the new ACQ (Alkaline Copper Quartenary), CA (Copper Azole), or CBA (Copper Boron Azole). Stainless steel or other special treated fasteners has to be used into these non-compatible pressure treated lumbers. Aluminum must be separated from contact with all treated wood since the soluble copper in the preservative is corrosive to aluminum. Likewise, dissimilar metals also require a protective barrier between them to prevent galvanic corrosion. Request FABRAL Techni- cal Bulletins #803, 106, and 107 for more information on treated lumber and dissimilar metals

Plastic, builders' felt, bituminous paint, caulking, or gas- ket material may be used to separate panels from treated wood and dissimilar metals. When utilizing aluminum panels in direct contact with steel, use a separator as described above and fasten with Stain- less Steel screws

Fertilizer, lime, acids, feeds, manure, soils, and many other compounds also cause corrosion in metal panels. Contact between metal panels and any potentially corrosive materials has to be pre- vented

Porous insulation materials may absorb and retain moisture, and should not be used in direct contact with metal panels. Use a vapor barrier such as polyethylene plastic or 30-lb felt to prevent moisture from contacting both the insulation and the metal panel

FABRAL's translucent panels are intended for siding applica- tions only. In all situations, foot traffic has to be avoided on translucent panels. Translucent panels used in roofing applications will break down in a short time and cause staining and premature corrosion of the metal panels below. If used on roofs, apply butyl caulking to separate the fiberglass panels from the metal. Translucent panels has to be cleaned and sealed regularly, as recommended by the translucent panel manu- facturer

Purlins, Girts and Roof Deck

The substructure to which the metal panels are fastened must be properly spaced and sufficiently thick to provide a roof or wall system able to meet required design loads

A 2" nominal lumber thickness provides the maximum pullout values for both screws and nails when the fasteners penetrate a mini- mum of 1" into the wood. Since 1" nominal lumber and solid decking are thinner, they provide somewhat lower pullout values. When utilizing purlins, FABRAL recommends a maximum spacing of 24" on-center (note that 5V requires solid decking). Pullout values decrease if the fasteners protrude completely through the purlins. Kiln-dried softwood is recommended for purlins or decking (pine, fir, hemlock, and spruce). Hardwoods are difficult to fasten into without splitting and contain tannic acids that are corrosive to metal panels. Green (non-kiln-dried) lumber may warp, twist, and shrink as the wood seasons fully, causing wavi- ness in the panels and loosening and leaking of the fasteners

Solid decking is highly recommended for all residential ap- plications. When usingsolid decking or sheathing, always use 30-lb felt or underlayment and plan on utilizing closer fastener spacing and larger diameter #14 screws. (Refer to the tables on page 31)

On re-roofing projects where the condition of the old decking

is in question, or where existing shingles will be left in place, new 2×4 purlins has to be fastened through the decking and into the rafters. This will provide a solid framework for attaching the metal panels. For more detailed information on Re-roofing applications, consult FABRAL Tech- nical Bulletin #721, Re-Roofing With Metal. Load tables are available for all FABRAL panels; contact FABRAL for additional information


Panel sidelaps should face away from wind driven rain. To accomplish this, begin by installing the first sheet square with the eave and gable at the down wind end of the roof, farthest away from the source of prevailing winds

In applications requiring a panel endlap, please refer to the detailed instructions in this booklet. For best results, lap panels as shown and install in the indicated sequence. All endlaps require seal- ant. When weather-tightness is critical, use sealant tape in all side- laps

To provide a drip edge, allow an overhang of 1 to 2 inches at the eave. At the gable edge, use a gable or sidewall flashing. This will keep weather out, prevent lifting in high winds, and provide a neat, fin- ished appearance. The trim and roofing sheet has to be fastened every 12 to 24 inches along the gable edge

Roof Pitch

The metal roofing panels shown in this manual require a mini- mum slope of 2 1/2 " per foot to ensure proper drainage. Refer to the rain- carrying table in this booklet for the maximum allowable panel length per slope that will provide adequate drainage. For longer slopes and lower roof pitches, contact FABRAL for other suitable profiles

Bending and Bowing

Aluminum roofing and siding sheets are rollformed from hard- ened, tempered metal for maximum strength. If a sheet must be bent, a gentle 90-degree bend is the maximum recommended. Metal should not be re-bent once it has been formed, nor should it be folded back on itself. When a metal roofing sheet must be installed on a curved roof, screws has to be installed at every overlapping rib at the sheet ends to resist the natural tendency of the metal to spring back. The standard fastening pattern is permitted over the rest of the sheet. When installing the metal panels shown in this booklet over a curved arch, the minimum radius of the arch is 18' for aluminum panels and 24' for steel panels. Use sealant tape or butyl caulking at all sidelaps and endlaps

Additional care and fasteners must be provided when securing the top and bottom purlins on an arched rafter building to prevent the curved panels from pulling the purlins loose from the rafters. Ring-shank pole barn nails, heavy wood screws, lag screws, or bolts are often used for attaching these purlins


Siding has to be installed utilizing the standard fastening and overlap patterns to ensure optimum performance. For strong, neat cor- ners use hemmed corner flashings. Do not run siding sheets all the way to the ground. Instead, provide a protective base of concrete, masonry, treated wood, or similar material and terminate the siding sheets 6" above grade

If siding sheets are installed horizontally, use sealant tape or butyl caulking at the vertical laps to ensure weather-tight joints. Install panels from the bottom up so that water is directed away from, and not

into, the lap joints