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Proprietary coated deck screws (C) Daniel Friedman Wood Framing Fasteners
Stud, Joist, Porch, Deck Board Screws & Nails

  • FRAMING FASTENERS, NAILS, SCREWS - CONTENTS: Structural Fasteners, screws, nails, bolts, hidden fasteners used for wood frame construction, including deck & porch construction. Choices of deck nails, screws, coated fasteners, and hidden fasteners for deck floor, railing, joist hanger, and other construction connectors. Using drywall screws, roofing nails, hanger tabs, or other improper fasteners for wood framing
  • POST a QUESTION or READ FAQs about structural fasteners, nails, bolts, or hidden fasteners for wood framing of buildings, decks & porches
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Choices of deck structural & flooring fasteners:

types of construction screws, nails, bolts to use when building a deck, railing, or exterior stair.

This article explains critical safe-construction details for decks and porches, including avoiding deck or porch collapse and unsafe deck stairs and railings.



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Guide to Selecting the Proper Deck & Porch Structural Fasteners, Screws, Nails, Lags, Bolts

Deck nails and screws (C) Daniel FriedmanThe Right & The Wrong Fastener Nails & Screws Used for Joist Hangers, Framing Ties, Framing Connector Plates

Article Contents

Our photo, above left, shows three fasteners we have found used with steel joist hangers. This photo shows the heads of each of these fasteners.

Joist hanger nail installed (C) D Friedman

Because the new wood preservatives ACQ (alkaline copper quat) and copper azole contain significantly more copper than the older CCA-treated lumber, they are estimated to be two to four times more corrosive to metals and galvanized coatings than the CCA they are replacing.

Roofing nails in joist hanger (C) D Friedman

Drywall screws in joist hanger (C) D Friedman

Comparing Joist Hanger Nails, Drywell Screws, Joist Hanger Tabs, & Utility "Construction" Screws - which are acceptable?

Deck nails and screws (C) Daniel Friedman

Stainless steel utility screws: At the top of our photo (red arrow at left) is a 1 1/4" stainless steel screw used by a contractor to secure joist hangers when building the deck shown at the top of DECK & PORCH CONSTRUCTION.

The orange arrow points to a drywall screw, and the green arrow to the proper nail for steel structural fasteners, a Simpson Strong-Tie N10 DHDG 1 1/2" hot dipped galvanized "joist hanger" nail.

Watch out: Although the stainless steel screw (red arrow) screw is also made by a company that makes structural fasteners, a quick look at the company's specifications for this screw revealed that the manufacturer specifically advised that this screw was not a structural fastener and should not be used with steel framing connectors.

What about those little "Tabs" on Joist Hangers - can I just nail those in and skip the joist hanger nails?

Joist hanger locating tabs and knock-ins (C) D Friedman

Watch out: the short answer is "no".

The locating tab (red oval in our photo at left) is intended to temporarily hold the joist hanger in place (just hammer it in) while you reach down into your nail apron to grasp a handful of joist hanger nails.

The tab is not a structural fastener and cannot be relied-on for that purpose.

Notice that the Tamlyn joist hanger shown in our photo provides for two joist hanger nails that will be hammered into the sides of the sides of the joist (two from each side), and three that will be nailed into the header or rim joist or ledger board (three at each side).

Our green arrows remind us of where we should see nails in the installed joist hanger.

Key Forces that Hold Nails & Screws in Wood as Structural Connectors

Nailing Stainless steel, galvanized, as well as proprietary-coating surfaced construction screws for use with treated lumber are available and of course are fine if used as recommended. But not the two screws shown in this photo and removed from decks we inspected.

In the deck we inspected and where these improper screws had been installed, the contractor agreed to remove the screws and to replace them using the proper fasteners instead.

Watch out when removing and replacing wood framing fasteners: Even then we were not quite sure that the deck was safely framed. Why?

The hole left by removing the wrong screws amounts to a "pre-drilled" opening in the ledger board or beam to which the joist hangers were later nailed. The holding power of a nail (or screw) fastener, the force that keeps the structure safely together, involves:

Shear force - force across the diameter of the fastener. The shear force resistance of a nail or screw is a function of the thickness and composition of the screw material.

Withdrawal force - the force that keeps the fastener from pulling out of the wood.

Screw fasteners have improved withdrawal force resistance because their threads cut into the surrounding wood.

Nails depend on friction for their resistance to withdrawal force - the "tightness" with which the wood member presses against the sides of the nail. When we nail into a pre-existing hole in a structural member, this withdrawal force may be compromised, especially depending on the diameter of the hole but also depending on the wood species and its dryness as well as the smoothness of the shank of the nail itself.

at DECK COLLAPSE Case Study we describe a serious deck collapse that occurred when the deck ledger pulled away from the building. The deck ledger discussed in that study had been nailed to the rim joist through siding, using too-small common nails, missing bolt connectors or other proper ties. The ledger, and thus the whole deck was unable to resist withdrawal forces.

The deck pulled away from the building and collapsed. Other mistakes exacerbated the failure and fall. People were injured.

Figure 4-5: Hidden fasteners for deck construction (C) J Wiley, S Bliss

Position of the fastener also is significant in withdrawal force of both nails and screws.

For the identical size, weight, and number of fasteners, a nail that is horizontal with respect to the components it is supporting has less withdrawal force imposed on it (in general) than one which is nailed upwards: nailing a board straight "up" to a ceiling joist or rafter imposes more withdrawal force on the nails than nailing a board horizontally onto studs in a structural wall.

Length of the fastener is also significant. The fastener must be long enough to penetrate the structural wood members deeply enough to provide sufficient resistance against withdrawal.

(That's why roof shingle nailing specifications, presuming the installation is over 3/4" plywood, expect the tip of the roofing nail to protrude through the 3/4" decking - to be sure that we have at least 3/4" of wood around the full-diameter shank of the roofing nail.)

Toe-nailing is particularly effective at improving the withdrawal force of nails used in framing construction. The crossing of nails past one another when nailed from opposing sides of a joist or stud forms a stronger connection than the same number of nails would provide if all placed on the same angle but just in one side of the framing member.

Most treatment manufacturers recommend that fasteners and hardware in contact with the new treated wood be stainless-steel, heavily coated hot-dipped galvanized, or proprietary fasteners tested and approved by the manufacturer.

New Wood Preservatives and Their Corrosion Effects on Deck Nails, Screws, Connectors & Fasteners

Hot-Dipped Galvanized Nails for Treated Lumber Decking

Simpson joist hanger nails (C) Daniel Friedman

These deck construction nails, such as the joist hanger nails shown in our photo above, have three times as much zinc coating as standard G60 connectors. Examples of G185 coatings include Simpson’s Z-Max or USP Connector’s Triple-Zinc. Best Practices Guide to Residential Construction explains:

When using lumber treated with ACQ or copper azole, use hot-dipped galvanized fasteners that meet ASTM A153 with a minimum of 2 ounces of zinc coating per square foot.

Some galvanized nails intended for deck construction are marketed as “doublehot- dipped.”

Connectors, flashings, and other hardware in contact with treated wood should meet ASTM A653, Class G185 (1.85 ounces of zinc per square foot of metal surface). Galvanized fasteners may stain redwood and cedar, however.

Typical[7] Nail Schedule for Metal Framing Connectors - Joist Hangers

Nominal Wood Joist Size Nails into Abutting Header
(through the connector)
(10d 1 1/2" joist hanger nails)
 
Nails into Joist
(through the connector)
(10d 1 1/2" joist hanger nails)
 
Single Joists
2x4 4 2
2x6 6 4
2x8 8 6
2x10 10 6
2x12 10 6
2x14 10 6
 

Typical[7] Nail Schedule for Metal Framing Connectors - Joist Hangers - Built-up Beams

Nominal Wood Joist Size Nominal Thickness (as number of 2x's making up the header or beam) Nails into Abutting Header
(through the connector - sum of both sides)
(10d 1 1/2" joist hanger nails)
 
Nails into Joist
(through the connector, sum of both sides)
(10d 1 1/2" joist hanger nails)
 
Built-up headers & beams: double, triple, quad or custom thickness, joist & truss hangers
2x6 2 - 2x6's (3" thick) 8 4
2x8 2 - 2x8's (3" thick) 12 6
2x10 2 - 2x10's (3" thick) 14 8
2x12 2 - 2x12's (3" thick) 14 8
2x14 2 - 2x14's (3" thick) 14 8
 
4x8 4x8 (3-1/2" thick) 12 6
4x10 4x10 (3-1/2" thick) 14 8
 
2x10 3 - 2x10's 14 8
2x10 4 - 2x10's 6 (review needed) 4 (review needed)
 

Stainless Steel Nails & Screws for Decks in Salt-Exposed or Wet/Humid Climates

In very wet or humid climates, or in areas subject to salt-water spray or deicing salts, stainless steel is the best choice. Stainless steel is also recommended for tropical hardwoods, which tend to cause staining with coated nails. Both types 304 and 316 stainless steel have been tested for use with the new wood preservatives ACQ and copper azole. Type 304 is suitable for above- ground applications. Type 316 is recommended in areas subject to salt or salt water.

Watch out: Never use stainless steel in contact with galvanized steel, as the galvanized coating will quickly corrode. Where fasteners such as nails, bolts, or lags are in contact with metal connectors, use the same metal for both components.

Proprietary Deck Screw or Nail Coatings

Proprietary coated deck screws (C) Daniel FriedmanMany decking screws sold in home centers have newer proprietary ceramic and epoxy coatings over an electro galvanized core.

Originally developed for use with CCA-treated lumber, many have now been tested and approved for use with ACQ and copper azole.

Our photo, left, shows two proprietary-coating coated structural screws used for decks; the right-hand most screw is hot-dip galvanized. This photo shows these 2 1/2" screws from the side view.

Grip-Rite Fas'ners® produces "PrimeGuard Ten" exterior screws that use a coating approved for exterior use with all types of treated lumber.

Prudential produces galvanized exterior deck screws such as the one shown at the right in our photo, above. These screws are warranted "for as long as you own your home" and are rated for use in untreated or CCA pressure treated wood in residential structures.

If using one of these fastener types, make sure that it is recommended by the manufacturer for the specific type of decking being installed.

Aluminum Deck Nails

Best Practices Guide to Residential Construction continues:

Watch out: Do not use aluminum fasteners, connectors, or flashings in contact with pressure-treated wood. The copper-based waterborne preservatives will cause corrosion and premature failure.

Also see PRESERVATIVE TREATED LUMBER.

Hidden Deck Fasteners for Deck Boards

Over time, face-nailed deck fasteners may loosen, stain the wood decking, or lead to splitting and water penetration. Particularly with higher-end decking materials, such as tropical hardwoods, more customers are opting for hidden fastening systems (see Deck & Porch Products, Manufacturers).

Each system is proprietary, and some require proprietary tools supplied by the fastener manufacturer. Some suppliers of hardwood decking recommend a specific fastener for their product and may sell the fasteners along with the decking. There are two types of systems. One, such as Deckmaster® (Grabber Construction Products), uses a right-angle bracket that fastens to the tops of the joists and screws into the underside of the decking. These are easiest to install if the installer has access from below the deck.

The other type uses individual fasteners that fit between adjacent decking planks and screw down into the top of the joist. These typically attach to the edges of the decking planks with clips or prongs.

A variation on this type called Eb-Ty (Blue Heron Enterprises) fits into slots cut into the edges of adjacent deck boards with a plate jointer (see Figure 4-5 below).

Figure 4-5: Hidden fasteners for deck construction (C) J Wiley, S Bliss

The biggest concern with hidden deck fasteners is whether they are strong enough to resist the tendency of deck boards to warp or twist. For that reason, they are best used with premium decking products, which are dimensionally stable. Tropical hardwoods and composite decking are good candidates for hidden fasteners.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Guide to Selecting the Proper Deck or Porch Floor Decking Fasteners

Whether using nails or screws, make sure to choose a product that is up to the task both structurally and aesthetically. In general, screws are more expensive to buy and install, but often they make for a neater job with fewer callbacks due to boards popping up. Construction adhesives specially formulated for treated wood may be used in conjunction with nails or screws.

Nails for Use with Deck Floors - Decking

If the decking is to be nailed, use either spiral-, twist-, or ring-shanked nails to resist pullout. When using pressure-treated wood, the fasteners should be either hot- dipped galvanized, meeting ASTM A153, or stainless steel Type 304 or higher

(see New Preservatives and Corrosion, above and see PRESERVATIVE TREATED LUMBER).

Galvanized nails sometimes cause discoloration with redwood, cedar, and tropical hardwoods, so stainless steel is a safer choice with these materials. Aluminum nails are also an option for redwood or cedar, but they should not be used with pressure-treated wood.

The bigger the head, the better the hold-down power. At a minimum, use a casing nail, preferably a common. Some manufacturers sell special decking nails with a head size in between the two. For 5/4" decking use a 10d (3-inch) nail. For thicker decking use a 16d (3 1/2") nail.

Deck Joist & Beam Sizing Tables & A Quick Rule of Thumb for Sizing Joists

Spans, sizes and spacings for deck joists and deck beams are discussed in detai
l at FRAMING TABLES, SPANS for DECKS

and are listed in Table 4-7 and Table 4-8.

Decking Spans for deck flooring  are shown in the Table 4-4 below.

[Click to enlarge any image or table]

[Table 4-8: Deck board spans for deck flooring (C) J Wiley, S Bliss

Screws for Use with Deck Floors - Decking

Power-driven screws are more expensive and a little slower to install, but they are the best choice since they do a better job of holding down the decking and are more easily removed for repairs.

For treated wood, use either hot-dipped galvanized screws that meet ASTM A153, stainless-steel multipurpose screws, or specialty decking screws with proprietary coatings tested and approved for use with the new types of wood treatments.

Multipurpose screws have a thicker shank and courser thread than drywall screws, giving them greater strength and better holding power. Some specialized decking screws also have cutting nubs under the head for self-countersinking in wood.

Others have special concave “pancake” heads for composite decking. The composite-decking screws leave a crisp hole in the decking surface without the typical pucker of excess material (mushrooming) around the screw head (see Figure 4-4 below).

Table 4-8: Deck board spans for deck flooring (C) J Wiley, S Bliss

In addition to Phillips-head screws, decking screws come with square-drive and star-drive heads that allow higher torque driving without stripping the head.

Also see DECK COLLAPSE Case Study (collapse of a new code-approved deck)

and DECK FLASHING LEAKS, ROT Case Study for an example of an older deck with rot and collapse due to improper construction and missing building flashing.

-- Adapted with permission from Best Practices Guide to Residential Construction.

Hidden Deck Screws

"Hidden" deck screws are structural fasteners for connecting decking that use proprietary screws or backer connectors that do not appear on the deck surface. See:

Basic building framing information is found at FRAMING SIZE & Spacing, Age, Types.

Spans, sizes and spacings for deck joists and deck beams are discussed in detail at FRAMING TABLES, SPANS for DECKS and are shown in Table 4-7 and Table 4-8.

Tips for Removing Coated Deck Fasteners & Screws

Reader Question: how can I remove the screws securing PVC deck railings from my deck?

I am trying to remove PVC deck rails from my deck using an 18 volt power driver and can’t budge most of the fasteners which are coated 2 ½ #8. In a lot of cases the heads have broken off, but most will not budge even with the driver set in the highest torque. Any ideas? - J.R. 30 June 2015

Reply:

Break them or cut them through with a hacksaw blade and reciprocating saw.

Reader follow-up:

Thanks ... unfortunately the screws are inside a PVC deck railing bracket and the bottom brackets are 36 inches down a PVC post sleeve! I even tied buying a speed out kit that “removes any damaged screws in 10 seconds” and that didn’t work.

Carpentry tools (C) Daniel FriedmanReply:

When I've had this trouble I've broken the screws by driving a flat bar through the interfaced connection.

The screws will snap nicely.

If there is a risk of damaging the deck rail or other PVC deck components with the flat bar, use two thin flat bars, drive them between the joined segments, then hammer a third flat bar or even a flooring chisel between them to break the fastener without gouging the PVC material.

The grey chisel near the top right in the photo shown at above left is a flooring chisel that can work in this application

If you can get a couple of thin flatbars and a thin cold chisel and IF your situation gives you a place to drive them, the fasteners will usually snap quickly. I've used this method to remove deck boards when the freakin' screws all stripped when I tried to unscrew them.

An alternative that works with wood joists and beams into which screws are driven is to use a long thin punch and drive the screws downwards into the underlying member.

Drilling the screw heads off will also sometimes allow pry up of the attached member from the secured-to member. Then the screw remains that projects up from the secured-to member can be clipped or snapped off. But I'd avoid drilling through PVC plastic rails in areas where a slipping drill bit makes an ugly mess.

...


Continue reading at DECK FASTENER CHOICES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see CONNECTORS, FASTENERS, TIES

Or see FRAMING CONNECTORS & JOIST HANGERS

Or see DECK CONSTRUCTION BEST PRACTICES - home

Or see DECK DESIGN & BUILD - home

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FRAMING FASTENERS, NAILS, SCREWS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING DECKS & PORCHES

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