The first step in doing a metal roofing installation is to choose metal roof panels, hardware, and flashing appropriate for the existing roof's pitch, decking, and framing. Making a detailed drawing will help to determine how many roofing panels and what hardware are needed. If the roof is to be installed over existing roofing materials, asphalt paper or furring strips may need to be installed between the old and new roof. Assembling the right tools in advance for a metal roofing installation will help the job go more quickly and smoothly. Carefully reading and following any manufacturer's installation instructions is also important.
Various metal roofing panel designs have differing roof-pitch requirements to ensure good drainage. Determine the pitch of the existing roof decking, then select from designs recommended for that pitch. In cases where the roof's pitch is relatively low, additional hardware and sealant may be required to ensure a watertight roof. Metal roofs are designed for use with either external or internal fasteners. Generally speaking, a metal roofing installation using external fasteners is easier to do. The type of roofing panels chosen will largely determine what types of fasteners, flashing, and other trims are to be used.
Before shopping for materials, prepare a detailed drawing of the metal roofing installation. Discuss the various assembly and hardware options with the dealer and confirm that the materials are compatible with the sub-roof. Inquire if the dealer has any videos or other advice for do-it-yourself (DIY) installations. Once purchased, all materials should be stored in a dry location unless they will be used immediately.
Tools needed for metal roofing installation include gloves with a good grip, eye protection, and an assortment of cutting and fastening tools. For smaller projects, cordless drill fastener attachments may be adequate, while, on bigger jobs, a dedicated impact driver is preferred. Similarly, a cordless drill nibbler attachment could be adequate for cutting across panel ribs, but large projects will require a power saw fitted with a metal-cutting carbide blade. Many manufacturers warn that using a portable grinder with an abrasive wheel for cutting can cause oxidization. Small hand-held metal snips designed to make right- or left-hand cuts are helpful for cutting around obstructions.
Before beginning the installation, read the manufacturer's directions completely and confirm that all the materials and tools needed are on hand. Generally, panels are installed from the gable or peak downward, in the direction opposite to prevailing winds that carry rain. Depending on the surface on which the roof will be installed, pre-drilling the sub-roof to accept fasteners will speed up installation. To prevent unsightly oxidation in the future, thoroughly clean off all metal particles once the roof and trim are in place.