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April, 2007

Sell the Right Fasteners

Make sure your staff stays up-to-date on the new materials and techniques exploding into the market.

By Gary Katz

Not long ago a friend of mine who lives above Malibu went into a local big box to buy siding nails for a small remodel on his ranch-style home. He was installing fiber-cement siding and wanted to be sure he bought the right nails.

Walking down the aisle, he saw every kind of fastener imaginable and carefully read each label. (He’s that kind of guy.) But none of the fastener labels mentioned fiber-cement siding. After searching a few aisles, he found a store employee in the paint section and asked which nails he should use?

That employee called another who called in another until a "hardware specialist” finally met my friend back at the fastener aisle half an hour later.

"You should always use galvanized nails outdoors,” the man said, handing my friend a box of electro-plated 2 1/2-in. box nails. "These will do the job for you,” he said. My friend pointed to the next stack, boxes marked "hot-dipped galvanized nails,” and asked, "What’s the difference?”

"Oh, you don’t want to use those,” the hardware specialist said. "They’re harder to drive and they bend real easy.”

So much for seeking out sound advice.

Since building product sales is fast becoming a "profession,” liability is an issue that cannot be ignored. For that reason alone, it’s imperative that your sales staff has access to the right facts about the products they sell. Sales staff should also provide top-quality advice to their customers. That’s true customer care.

"Tradition” No Substitute for Training

I remember my father’s carpenters pouring a foul-smelling solution over their framing nails. It wasn’t until I met Larry Haun (author of The Very Efficient Carpenter, Taunton), that I learned what that stuff was—gas-wax. The mixture was paraffin and gasoline left in the sun, and then later poured on top of all new nails. Once the gas evaporated, it left a wax coating on every nail. Even I could almost sink those nails with a single swing. That’s just one piece of tradition that’s illegal today, though coated nails that sink almost as easily are available.

In fact, there are more types of fasteners today than you can count. No area of construction better exemplifies the flood of new products and changing technology, and for good reason: Today the type of fastener you use must be matched to the type of material you’re installing and to the geographical area in which you’re working.

Stainless Steel

Fasteners come in different profiles and styles, and in different materials and coatings. The highest-quality fasteners are made from stainless steel, which should always be the choice for exterior trim, siding, and decking if there’s any question about corrosion.

Though stainless steel was developed nearly 90 years ago, it has only become common on job sites in the last few decades.

There are three different types of stainless steel fasteners used in construction, all in the 300 series: #304 is the most common and the softest. The difference between #304 and #305 is barely noticeable on a hardness chart; both are a mixture of about 18% chromium and 8% nickel. But the third type, #316, includes molybdenum, which increases the hardness by as much as 10%, as well as improving corrosion resistance.

According to Lee Zinsle, technical support manager for Senco Products, stainless steel #316 fasteners aren’t used often in pneumatic tools because they are too hard. (Senco manufactures stainless steel screws and nails for their power fasteners in grade #304 only.)

"Though #316 won’t rust,” Zinsle says, "it isn’t as easy to form and it eats up your tooling. For pneumatic fasteners, #304 is the best bang for the buck.”

Stainless steel nails are harder than common steel nails, but stainless steel screws aren’t. Common steel nails are rarely hardened except for special applications, while screws almost always are. That’s why it’s a lot easier to twist off the head of a stainless screw than a steel screw of the same size: A standard #8 steel screw has a breaking point of approximately 50 in. lbs. of torque. Stainless screws, on the other hand, stretch, which means they don’t snap at a pre-determined point. Still, a #8 stainless screw can only take about 24 in. lbs of torque before it twists and breaks. That’s why you should move up one wire-diameter size whenever you use stainless screws. For instance, if you normally use a #8 steel screw, move up to a #10 in stainless steel, which will handle about 33 in. lbs of torque.

Galvanized Fasteners

There are three different types of galvanized fasteners. Let’s dispense with the electro-galvanized type right away, because they’re not recommended for exterior trim, siding, or decking: James Hardie warns that electro-galvanized nails are "acceptable but may exhibit premature corrosion.”

The most durable zinc-type coatings are hot-dipped and mechanically applied galvanization. Hot-dipped is preferred by most manufactures, and Senco even offers some framing nails with a hot-dipped coating. However, screws can’t be hot-dipped because the coating fills the screw-head recess and interferes with the threads. Instead, screws are mechanically galvanized.

While the hot-dip process is easy to imagine, the mechanical galvanizing process isn’t quite as simple. In some cases, zinc and other proprietary chemicals are placed in a tumbler with glass beads. As the tumbler turns, the beads peen the metal powder onto the steel, creating a metal-to-metal bond. Another alternative uses a dip and spin epoxy-based coating over a layer of yellow zinc dichromate.

However, all galvanization is sacrificial, which means it slowly deteriorates. (It’s that slow deterioration that protects the steel fastener underneath.) Therefore, choosing the right fastener means you must gauge the life of the project.

Most decks are built to last 15 to 20 years, which is easily within the life of a properly maintained galvanized fastener. But for high-end work, and especially for projects in more corrosive environments such as near the ocean, stainless steel is the way to go.

Additional Coatings

In addition to galvanized coatings, several manufacturers provide special coatings for corrosion-resistant nails and screws.

Manufacturers’ recommend these coated fasteners for decks with ACQ-treated joists. Although the barrier coating that protects the screws and nails will break down eventually, they will still easily outlast most decking materials.

Ringshank and Screwshank

Withdrawal is important when it comes to fasteners, which is why gas-wax isn’t legal anymore. However, Sencote is, and it works better than wax anyway.

Sencote helps lubricate nails and makes them easier to drive. As these air-driven nails penetrate wood, heat from friction liquifies their coating, making them easier to drive. More importantly, when Sencote cools and solidifies, it acts like a glue, increasing the withdrawal strength of a nail. That protects against pullout, and prevents squeaking floors and potential framing failures. Senco’s stainless steel nails are also coated with Sencote.

Profiles and fastener shapes also affect withdrawal strength. Ringshank and screw shank nails are the best example of mechanically improved fasteners, and each is meant for a specific type of wood.

Ringshank nails with chisel tips are best used in soft wood since the fibers tear easily, yet the wood has a memory and will return closely to its original position. Screw-shank nails found mostly in the furniture and pallet industry, are best used on hardwoods because they will turn 1 1/2 times for the length of the fastener, which prevents wood-fiber tearing and ensures stronger holding power.

While Sencote and ringshank nails are great improvements over traditional floor-fastening systems, and they help reduce squeaks, the best practice is still to use screws on all floor sheathing and stair treads.

Next-Generation Preservatives

When the treated lumber industry stopped offering CCA (Chromated Copper Arsenate) treated lumber for residential uses, some alternative preservatives proved more corrosive, and required the use of different fasteners than were recommended for CCA. The latest generation of treated wood from the three major preservative manufacturers—(MicroPro from Osmose, Wolmanized L3 Outdoor Wood from Arch Wood Protection, and, set to launch later this year, Ecolife from Viance)—are said to be less corrosive on fasteners.

While stainless steel is the best choice for long-term use with more corrosive wood treatments, hot-dipped galvanized fasteners are acceptable and provide a definite cost savings. But nails aren’t the only concern. Galvanized joist hangers will also corrode sooner. Informed contractors are now protecting galvanized hardware by wrapping the ends of joists with protective sleeves and membranes. (One example of this is York Wrap; www.yorkflashings.com/ res_accessories.asp).

But for joist hangers, there’s more than coatings and membranes involved. You have to know the correct nail size, which is specified by hardware manufacturers such as Simpson Strong Tie (www.strongtie.com).

For Senco’s Positive Placement nail guns, designed specifically for installing joist hanger fasteners, the company produces three different wire sizes (.131, .148, and .162) in varying lengths. Installing the wrong size nail in a joist hanger can be a fatal mistake. For instance, hanger nails in wooden I-Joist flanges shouldn’t exceed 10d (.148) in diameter or the wooden nailer may split. Yet using a fastener with a wire diameter that’s too thin won’t provide the required support strength. Both the hardware supplier and the installer should know which fasteners are required.

Decking Materials

As I noted earlier, coated nails and screws are acceptable in most decking materials. The best rule is gauging the fastener type by the quality of the decking material. For high-end composites, redwood, and Ipe, or for boat docks, stainless steel is the only choice. Stainless fasteners cost only about 15-20% more than galvanized, a small price to pay to ensure longevity for both the product and your reputation.

Fiber Cement Siding

James Hardie recommends hot-dipped galvanized nails for fiber-cement siding, though stainless steel is preferred, especially if your project is in a high-humidity area or near a large body of water like the ocean. But size matters too. When fastening siding, the size of the nail or screw head makes a big difference. Exposed siding nails must have a .221 head, slightly smaller than 1/4 in.; blind nailing is acceptable using 11ga. roofing nails with .371 in. heads; and screws must also have a larger heads, .323 (slightly smaller than 3/8 in.).

So what do you do with all this information? I’ve been buying my finish material from the same store for more than 20 years. Every time I place an order, they ask an endless number of questions. Like their other customers, I wouldn’t think of buying from anyone else, and not because of their low prices. I like all the questions. The sales team believes that if one of their customers is missing something on a job, it’s not just the contractor’s fault, but it’s the salesperson’s fault, too. All those questions prevent job site slowdowns, and they prevent costly liability problems, too.

But you can’t ask questions unless you know about potential problems. That’s why reading professional journals and keeping abreast of the latest material and installation requirements is so important to building product professionals.

GARY KATZ, with nearly 40 years experience in the industry, is a contributing editor to Fine Homebuilding magazine, a frequent contributor to the Journal of Light Construction, and produces the Katz Roadshow— Carpentry Clinics at lumberyards all over America. To learn more, visit his web site:


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