Guide to Ordering Metal Roofing

Types of Metal Roofs

• Metal roofing comes in different styles and types. Depending on the metal used, the roofing may have different rates of corrosion and different weight. Galvanized steel is the lowest price, but has the shortest life span. Galvalume is a galvanized steel and aluminum alloy that is a little bit more expensive than galvanized steel, but it is highly resistant to corrosion. Aluminum roofs are rust-resistant and durable, but not hail-resistant. Copper roofs are extremely attractive and durable but prone to stain from water runoff. Other selections include zinc and zinc alloys, like terne.

Clip and Through- Fasteners

• Metal roofs are attached to the frame of a building in either clip or through-fastening systems. Through-fastening is a nail or screw driven through the metal roofing straight into deck, purlins or lathe. The head of the screw or nail is generally left exposed and can be prone to rust. Clip-fasteners attach the metal panels to the purlins beneath. Screws and nails are driven through the clip beneath the panel rather than through the panel.

Standing Seam vs. Sheet Metal

• Standing seam roofing panels have a raised visible seam along the length of the roof. Commercial buildings will benefit from wide panels of standing seam metal roofing. A residential home, however, needs narrower panels due to the many small sections of roof that cover it. Sheet metal roofing includes corrugated metal, 5V crimp and R panel types. Sheet metal is usually made from Galvalume or galvanized steel, but may also be made from other materials. Metal tiles, shakes and shingles are available to homeowners that desire a traditional roofing style with the durability of metal.

Diagramming the Roof

• After selecting your roof type and fastener type, draw a diagram of the roof of the building from the bird's eye view. Measure the perimeter of the roof. Measure the perimeter of each section of the roof. The sections are the various rectangles and triangles sloping upwards and down on the roof. Measure all eaves, valleys, hips, dips and gable edges to ensure that you account for every needed measurement.

Selecting the Number of Panels

• Some manufacturers will request a copy of your roof diagram and cut panels to precisely fit your roof measurements. Other manufacturers will require you to order panels based on their panel sizes and measurements. Check with the manufacturer to ascertain their calculation method for determining the number of panels needed for your roofing project.