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ROOFING INSPECTION & REPAIR
AMERICAN CEMWOOD ROOFING
BEST ROOFING PRACTICES
BUILT UP ROOFS
CATHEDRAL CEILING VENTILATION
CERTIFICATIONS for ROOFING CONTRACTORS
CHIMNEY FLASHING Mistakes & Leaks
COLD WEATHER ROOF TROUBLE
DECKS, ROOFTOP CONSTRUCTION
EPDM, RUBBER, PVC ROOFING
EXTRACTIVE BLEEDING on SHINGLES
FIRE RETARDANT PLYWOOD
FLASHING on BUILDINGS
FLAT ROOF MOISTURE & CONDENSATION
Green House or Solarium Roof Leaks
HEAT TAPES & CABLES on Roofs for Ice Dams
ROOF ICE DAM LEAKS
MASONITE WOODRUF FIBERBOARD ROOFING
NOISE CONTROL for ROOFS
PLASTIC ROOFING TYPES
PVC, EPDM, RUBBER ROOFING
ROOF ARCHITECTURAL STYLES - PHOTO GUIDE
ROOF CLEANING RECOMMENDATIONS
ROOF COLOR RECOMMENDATIONS
ROOF INSPECTION SAFETY & LIMITS
ROOF LEAK DIAGNOSIS & REPAIR
ROOF NOISE TRANSMISSION
ROOF REPLACEMENT SNAFUs
ROOFING FELT UNDERLAYMENT REQUIREMENTS
ROOFING MATERIALS, Age, Types
SADDLE CONSTRUCTION at CHIMNEYS
SNOW GUARDS & SNOW BRAKES
STANDARDS for ROOFING
STRESS SKIN INSULATED PANELS
TEST LABS - ROOF SHINGLE
TREES & SHRUBS, TRIM OFF BUILDING
TRUSSES, Floor & Roof
UNDERLAYMENT REQUIREMENTS on ROOFS
VENTILATION in BUILDINGS
WALK-ON ROOF SURFACES
WARRANTIES for ROOF SHINGLES
WORKMANSHIP & ROOF DAMAGE
This article describes types of metal roofing products and metals: metal roof choices, installation, inspection, metal roof defects, roofing repairs, and metal roof product sources. Page top photo, the Richard B. Fisher Center for the Performing Arts at Bard College, architect Frank Gehry. Also see METALS USED IN ROOFING and see our metal roofing home page, METAL ROOFING.
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Originally associated with agricultural and commercial buildings, new metal roofing products aimed at the residential market are designed with simplified installation systems and offer more choices in materials, finishes, and design.
The installed cost of premium metal roofing is three to four times more than asphalt shingles, but metal roofing offers a variety of attractive benefits:
Noise Transmission of Metal Roofs
One frequently cited disadvantage of metal roofing is that it generates a noticeable noise when struck by rain, hail, or even dropping acorns. If installed directly to purlins with no roof sheathing, the noise might be heard in the building interior. However, when installed over a solid substrate, with normal levels of insulation, the noise should not be noticeably different than with other roofing types.
Details about roof noise transmission are at ROOF NOISE TRANSMISSION.
Walkability of Metal Roofs
Panels laid flat on solid decking are generally walkable. However, if panels are installed on battens, workers should be careful to step directly over battens or to use planking that spans multiple battens. Modular shingle panels generally use fairly light-gauge material, but it is stiffened somewhat by the stamped textures. In general, modular steel panels are walkable, but aluminum ones should be reinforced by foam inserts in sections expected to see a lot of foot traffic.
Also see Roof Slope or Roof Pitch Definitions
There are three general types of residential metal roofing
As summarized in Best Practices Guide to Residential Construction, chapter on BEST ROOFING PRACTICES, all coated steel materials, however, are vulnerable to corrosion at field-cut edges— although Galvalume® is the least affected Table 2-10 below lists the advantages, drawbacks, compatibility, and life expectancy of galvanized steel roofing, aluminized steel roofing, galvalume, aluminum, copper, and zinc metal roofing products.
[Click any table or image to see an enlarged version.] Following this table is our complete list of metal roofing products.
According to the US NPS,
Minimum Slope Requirement for Metal Roofs
Below we provide photos of both curved and straight traditional metal barn roofing. Also see corrugated roofing and standing seam roofing below.
Barn Roofing? Our friend, builder, and home inspector Steve Vermilye pointed out that "barn roofing" works fine on barns where ventilation is important and a few drops of water falling on a cow are harmless.
But when we find this low-profile corrugated roofing with simple nailed seams installed over a home where occupants expect to stay dry, we are not so sure this is the best option, even if it is one of low cost.
At CORRUGATED ROOFING we discuss all types of corrugated roofing products: metal and others.
The standing seam copper roof shown below protects Ely Hall, originally the Alumnae Gymnasium, William M. Tubby, architect, 1889, Vassar College, Poughkeepsie NY.
Examples of fastening details for the installation of copper roofs to the building roof deck or structure are discussed under metal and standing seam roofing below.
See COPPER ROOFING for details about antique and modern copper roofing products.
The patched corrugated metal roofing shown below (left) covers a pre-1900 home currently used as a parsonage in Dover Plains, NY. The modern corrugated roofing shown at right tops a gambrel-roofed barn in New England. More on roof shapes and architecture is at ARCHITECTURE & BUILDING COMPONENT ID.
A CORRUGATED ROOFING we discuss all types of corrugated roofing products: metal and others.
The metal roof shingles at below-right found on a New York home are steel, coated with a granular material that from the ground can be mistaken for asphalt. Carson Dunlop's metal roof shingle sketch (below left) provides additional details about this roofing option.
Details about metal shingle roofs of this type are at MODULAR METAL ROOF SHINGLE SYSTEM.
The antique embossed metal shingles (below) are found on the Justin Morrill Smith historic homestead, Vermont.
The rusted metal shingles on the church roof (Clintondale, NY) shown in our photo (left) demonstrate more about the history of how metal roofing was used in the U.S. Here the original wood shingle roof was re-roofed using metal shingles, probably before 1900.
Quoting Grapefine Design Guidelines:
Carson Dunlop's standing seam metal roof sketch (below) includes a sketch of soldering used to connect flat metal roofing panels.
Watch out: large expanses of metal roofing with soldered connections may flex and break open the soldered joints due to thermal movement.
Standing seam metal roofs were widely used throughout North America and in modern forms remain in use today as a very durable roof covering, especially if the metal coating or paint is maintained.
Carson Dunlop's standing seam metal roof sketch (left) shows how sheet metal roofing is secured to the roof deck using cleats. Sections of metal roofing may be joined by
see STANDING SEAM METAL ROOF INSTALLATIONfor details about standing seam roof installation, flashing, maintenance, repair.
Our rusted standing seam barn roof photo (below left) demonstrates a common roofing sequence history: metal roofs were installed over worn-out wood shingle roofs as a more economical way to re-roof the building.
A second rusted standing seam barn roof is at below right, and our third standing-seam photo below shows a modern coated standing seam roof on North Henderson, the computing facility at Bard College, Annandale, NY.
See STANDING SEAM METAL ROOF INSTALLATION for details about standing seam roof installation, flashing, maintenance, repair.
Best Practices Guide to Residential Construction lists these producers and sources of metal roofing, metal roof fastening systems, and related metal roofing products
-- Adapted with permission from Best Practices Guide to Residential Construction.
Frequently Asked Questions (FAQs) about metal roofs, metal roof choices, installation, inspection, troubleshooting, leaks, life, warranty, & repairs
Question: is there a recommended distance between seams on a standing seam metal roof?
First, thank you for your excellent site. A great example of what makes up for the crappy stuff that draws so much criticism. This is for Vermont, where our 40 by 50 Seventies ranch house needs a new roof. We were thinking of going from asphalt to standing seam, though it's not a highly pitched roof and the studs are 20 inches on center. Is there a recommended distance between the seams for a house like that, in a northern climate that sometimes sees heavy snowfall sometimes made heavier by subsequent rain?
Reply: Seam height vs. pitch on standing seam roofs
The spec for metal roofing seam distances is not about the horizontal distance between seams - that's pretty standard and up to the manufacturer. But the seam height above the roof surface is of interest on lower slope roofs if we want to be sure the roof won't leak. You'll see Eric's hand and mine in the photo at below left, and a standing seam metal roof clip installed to the decking at below right.
You want to discuss the slope of the roof with the roofing supplier. For the metal roof we installed atop my office/lab a few years ago, as the slope was rather low (less than 4/12) we were assured that a standing seam roof would work perfectly well (New York) provided we installed one that had taller seams. I.e. taller, not closer together, on lower slopes.
The metal roof is secured not to the rafters but to the roof decking which itself is secured to the rafters. As you may have seen, the connection of roof to deck is by clips that mount over a seam and are screwed to the deck. Then the clip is covered by the next overlapping seam cap of the next section. That's why rafter spacing shouldn't be an issue. Also as a metal roof is typically lighter than most other options (asphalt for example) the rafter spacing should be less of an issue than before - with respect to the weight of the roof.
Details are at STANDING SEAM METAL ROOF INSTALLATION.
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