fasteners coating on roofing screws

What is Fasteners coating?

Fasteners and metal screws of High tensile class 12.9 are usually furnished unplated with an oil moistened finish, where the triumphant majority of lower tensile fasteners are coated; this includes Metric class 8.8, USA grade 5, and lower grade/class.

Large qualities of fasteners are coated by the manufacturer in their factory plating plants or subcontracted. With smaller quantities and strange finishes, the distributor will subcontract to a neighborhood coater.

The coating is primarily for corrosion resistance of roofing screws and may also be for thread lubrication and, in many instances, for aesthetics for furniture and similar industries.

Importance of coating on a Fastener/screw

Quality is essential for any product selection. When it involves fasteners, quality is defined by durability and resilience. Clients want fasteners that may last!

Because fasteners connect or combine elements, structural integrity needs to employ the correct type. Similarly, appropriate coatings make sure the longest lifespan for your fasteners by providing a level of protection for the metal underneath.

In addition, damaged or rusted fasteners may be dangerous and are costly to interchange. Therefore, it is important to induce the correct reasonable coating for the work.

Manufacturers depend upon the results of salt spray testing to understand the corrosion resistance of screw coating. The more hours the salt aerosol container be applied to a coating before oxidation or rust occurs, the higher the coating. If you would prefer to know more about these tests.

What sizes do Fasteners come in?

Fasteners (bolts, screws, etc.) that belong to the “inch” series and their size is described as diameter, the number of threads per inch (if used with a nut or during a threaded hole), and length in inches.

Diameter is given as one of the two-digit numbers for smaller sizes and as a fraction for larger sizes. All told cases, the larger the quantity, the larger the scale. Consequently, a #8 screw is larger than a #4 screw, even as a 3 inch bolt is larger than a 2 inch bolt.

The diameter of wood screws, sheet screws, and other fasteners that are not used with a nut is specified by a one or two-digit number such as 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20, 24 (not all screws are available altogether sizes).

Sometimes, seldom though, you will see flat solid roofing screws sizes listed as a fraction like 5/16 or 3/8, but, generally, the diameter of those screws are specified as a one or two-digit number.

Unlike metric fasteners, a bigger number indicates a finer thread. It is because threads per inch are the reciprocal of the pitch. Common threads per inch sizes are: 4, 4-1/2, 5, 5-1/2, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 18, 20, 24, 28, 32, 36, 40, 48, 56, 72, 80. A number of the explanations for employing a coarse threaded fastener are:

  • Less chance of stripping or cross-threading
  • Coarse threads are not as easily damaged by handling or during shipping
  • Some materials tap better when using coarse threads
  • Fine threads, though, offer these and another fine attribute

Length is solely the length of the screw or bolt, in inches. For binding, button, fillister, flange, hex, pan, round, socket, and low socket, square and truss heads, measure the length from under the top.

Top Coatings used on Screws

1. Brass, Bronze, Chrome or Nickel-Plated

Both brass and bronze are very immune to corrosion. Chrome and nickel-plated finishes provide some corrosion resistance to the metal, but they are typically chosen for their aesthetic finish instead of for strength and protection.

2. Clear and Yellow Zinc

Zinc is one every of the foremost popular fastener coatings available. This coating is comparatively inexpensive to use and protects against rust, making zinc-coated fasteners perfect for humid environments.

Yellow zinc gets its name from its electroplating process, creating a more golden color than clear zinc coatings. As a result, yellow zinc-coated fasteners are ideal for situations where the merchandise will probably return in-tuned with water or other liquids.

3. Hot Dip Galvanized

Standard zinc plating is popular, but hot-dipped galvanized coatings provide a thicker layer of zinc on the fastener’s surface, making this a more robust corrosion-resistant coating. Also remarked as HD, hot-dip galvanized coatings are ideal for outdoor use, particularly coastal areas where the salt content is higher.

In addition, HD-coated fasteners take a significantly longer time to rust than those with other coatings.

4. Electro-Galvanized

Known as EG, this coating uses a thinner layer of zinc, offering frugal corrosion protection. EG fasteners are typically employed in areas where less corrosion protection is required, like kitchens and bathrooms. Most fasteners employed in roofing are electro-galvanized still.

5. Grey Phosphate

Grey phosphate is another popular style of coating meant to elongate fastener lifespan. Phosphate coatings reduce friction, making them great for fasteners that require to be inserted. However, this coating should only be used indoors, and gray phosphate-coated fasteners should not be used with treated lumber.

6. Ceramic Coated

Ceramic coatings are not as immune to corrosion as chrome steel, but they are often employed in marine applications to protect saltwater spray. In addition, these coatings are often designed to pass 500- and 1,000- hour salt spray tests.

Metal Roofing Screws Vs Traditional Screws

Something as small and easy as screws and fasteners is easy to disregard as a significant component of a construction project. For example, for metal roofs, fasteners frame but 1% of the whole installation cost, yet they will end in 100% of the roof’s failure.

Your roof can fail from broken fasteners, incorrectly installed fasteners, exhausted sealing washers, or the best of errors: using the incorrect screws.

When installing exposed fastener panels, fasteners with rubber sealing washers are wont to increase the weather tightness of the panels and keep water out.

Concealed fastener panels use fasteners with an occasional profile head to avoid contact with the underside of the roofing panel.

Concealed fastener panels that use clip attachments, like snap lock standing seam, generally use pancake head style fasteners. A system that does not use clips, like nail strip standing seam, uses extra low profile style fasteners.


At BDN, we manufacture metal roofing and metal siding panels for a large form of commercial and residential projects. We have worked with thousands of contractors and continuously receive questions on which sort of screws to use.

There are many various factors you have got to contemplate when choosing the right stainless steel roofing screws for your metal roofing or siding project.

The type of fastener you utilize depends on installing exposed fastener panels or concealed fastener panels. Wavy corrugated and R Panel are samples of exposed fastener panels. Standing seam or flush wall panels are a concealed fastener panels.

There is a lot to choose from, and the options around you can confuse you. However, you can contact our experts for help in screws for metal roof installation at any hour!