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Photograph of really worn out asphalt roof shingles Terne Metal Roofing Types, Product Sources, Installation, Defects, Repairs

This article describes types of terne metal roofing and other terne metal products used on buildings.

Page top photo, the Richard B. Fisher Center for the Performing Arts at Bard College, architect Frank Gehry - this is not a terne metal roof. Terne metal roofing and gutter photos wanted - CONTACT us.

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Terne Metal Use on Building Roofs & Exteriors

TERNE METAL ROOFING, or Terne II  coated metal roofing are used where copper roof runoff or corrosion are special concerns.

Terne coated stainless steel roof panels (Terne coating is a a zinc-tin alloy metal coating process that gives extra corrosion resistance. Terne metals produced acccording to US ASTM A308 are expected to contain alloys copper, nickel, chromium, molybdenum, vanadium, titanium, columbium, and boron, at alloy mixes depending on the specific product requirement.

Other terne coatings using lead or tin can present an environmental contamination worry from lead leachate found in roof runoff.)[1] Some terne-coated metals described by the galvanized-zinc industry use a terne coating that is comprised of 95-97% lead and 3-15% tin alloyed together. - American Galvanizers Assoc. (ret. 2015).

In the UK "Ternplate" is defined as follows:

Terneplate, steel sheet with a coating of terne metal, an alloy of lead and tin applied by dipping the steel in molten metal. The alloy has a dull appearance resulting from the high lead content. The composition of terne metal ranges from 50–50 mixtures of lead and tin to as low as 12 percent tin and 88 percent lead.

The tin serves to wet the steel, making possible the union of lead and iron, which would otherwise not alloy. Terneplate is made by a process similar to galvanizing or tinplating—i.e., by dipping the sheets into a series of heated baths, the first of a zinc chloride flux, followed by the molten terne metal, and finally one of palm oil.

Terneplate has the strength and formability of steel and the noncorrosive surface and solderability of terne metal. While it is still used for roofing, gutters and downspouts, and casket linings and in the manufacture of gasoline tanks for automobiles, oil cans, and containers for paints, solvents, resins, and so on, it has largely been replaced by other, more durable steel products that are easier to manufacture. - Encyclopedia Britannica, - retrieved 20 April 2015, original source: http://www.britannica.com/EBchecked/topic/588065/terneplate

According to the US NPS, "Terneplate was first produced in United States in New York in 1825. Joseph Truman of Philadelphia patented the lead coating of tinplate in 1831. Later production combined the lead and tin into a single coating.

Called variously "leaded plate," "roofing tin", and "roofing plate," terne was cheaper than a pure tin coating, but its properties were very similar. Domestic production of terne was twice that of tin when it was chosen to roof the buildings of the 1893 World's Columbian Exposition. In the next few decades terne replaced tin completely in American production as steel replaced iron as the base metal. "

According to The Metal Intitative,

Terne metals are produced by coating carbon steel, stainless and other select metals with a specially formulated alloy consisting of zinc, tin and trace amounts of other elements in order to dramatically increase a metal’s corrosion resistance as much as ten times.

When terne was first used, during the colonial era, it contained roughly 80 percent lead and 20 percent tin. However, in the latter half of the 20th century, as lead was found to have potentially detrimental health effects, the lead/tin alloy had to be replaced. Seven years of metallurgic research and development produced a new and superior zinc/tin alloy in the mid-1990s. This new alloy, proven through ASTM corrosion resistance testing, provides improved performance and aesthetics over the original, minus potential risk to health.

Besides stainless and carbon steel, the zinc/tin alloy may also be applied to other metals such as copper, bronze, tin and titanium.

Available in a variety of gauges and widths, today terne metals are used on industrial, commercial, institutional, and residential structures for roofing, gutters and downspouts, siding, soffits, fascias and numerous other architectural applications.

A terne roof using a carbon steel substrate can easily last more than 100 years with very little maintenance required.

According to Follansbee, a West Virginia roofing company

Terne II roofing (also coated with zinc and tin), offering enhanced corrosion resistance, can be used in flatlock, standing seam, and vertical metal wall covering designs in any application where original Terne was used.

The company adds that with Terne II roofing the material should be painted as soon as conditions permit.

Oxide formation is slower than with the original Terne and the wait for proper painting conditions provides substantially less risk.

Tin plated iron and Terne Roofs - according to the US NPS, on early U.S. buildings, "Rolled sheet zinc appeared in the United States in 1816, as roofing in New York and as downspouts and gutters in Baltimore. Though more than seventy houses in New York had zinc roofs by 1837, it was out of favor by 1840. The popularity of the material was cyclical in the next decades, never matching iron and steel with their various coatings."

Terne Metal Specifications & Standards

Abstract

This specification covers sheet steel in coils and cut lengths coated with lead-tin alloy by the hot-dip process. The material, also known as terne-coated sheet, is available in four designations as commercial steel, deep drawing steel, extra deep drawing steel, and structural steel. Amount of copper, nickel, chromium, molybdenum, vanadium, titanium, columbium, and boron shall conform to the chemical composition requirements of this specification. Yield strength, tensile strength, elongation, and bending shall conform to the mechanical property requirements.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This specification covers sheet steel in coils and cut lengths coated with lead-tin alloy (terne metal, see 3.2.3) by the hot-dip process. This material is commonly known as terne and is used where ease of solderability and a degree of corrosion resistance are desirable. It is especially suitable where resistance to gasoline is required. Terne-coated sheet is also used for stamping, where the coating acts as a lubricant in the die, lessening difficulties in drawing. The weight of coating, always expressed as total coating on both sides, shall be specified in accordance with Table 1.

1.2 Material furnished under this specification shall conform to the applicable requirements of the latest issue of Specification A924/A924M, unless otherwise provided herein.

1.3 Terne-coated steel is available in a number of designations, types, and grades.

1.4 This specification is applicable to orders in either inch-pound units (as A308) or SI units (as A308M). Values in inch-pound and SI units are not necessarily equivalent. Within the text, SI units are shown in brackets. Each system shall be used independently of the other.

1.5 Unless the order specifies the “M” designation (SI units), the product shall be furnished to inch-pound units.

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Terne Metal Roofing Sources, Products, & Manufacturers

Best Practices Guide to Residential Construction lists these producers and sources of metal roofing, metal roof fastening systems, and related metal roofing products

Metal Roofing Articles


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