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A BOUT 30 years ago. an idea was ll,born that would revolutionize rhe way Americans enjoyed their backyards. Homeowners, in an effort to increase living space, pushed into the outdoors. Now their backdoor led to open space complete with benches, tables, and barbeques.

To create this space, homebuilders and remodelers took their current building practices and utilized them to create the sundeck. They nailed floor joists and band boards together, and topped them with treated decking. They supported one end of the deck by fastening it to the existing house. The other was supported by a beam, post and footings. For three decades, the basics haven't changed.

Unfortunately, there was a flaw in this practice. Being outside, the nailed deck connections are subjected to wet and dry cycles, freeze and thaw cycles. wind. and in some areas seismic activity. Nails cannot be expected to withstand such demanding conditions and remain tight over the long haul. A nailed sub frame cannot stay together when exposed to the elements. Reports of deck collapses began to show up in local nervs. The scope of this problem can be seen by searching the Internet for terms similar to "deck collapse."

And, according to a study of five years rvorth of deck failures by the U.S. Forest Products Laboratory in Madison, Wi., "nearly every collapsed deck had been attached rvith nails. rather than bolts, and investigators had pinpointed nails as the cause of the collapse."

Usually, the failure came at one of three critical points of connection: the ledger board. rail post. or stairs.

A deck builder relies on the house for structural support, specifically the rim joist of the house. Rim joists are usually held in place rvith nails driven into the end grain of the floor joists. They may or may not be top nailed through the sub floor. They certainly were not designed to resist the pullout force of a several-thousand-oound deck. Over time, repetitive loading of the deck causes these nails to withdraw and the deck to collapse.

A similar design flaw exists in the deck's railing system. Usually, the posts for the railing are attached to the bandboard of the deck. When bolted together, the post and the bandboard have a very strong connection. The weak connection is between the bandboard and the deck joists. Usually, the bandboard is installed rvith three or four nails driven into the end grain of the deck joists. When someone leans on the post. it acts like a crowbar trying to pull the nails from the joists.

Stairs are usually nailed to a deck's subframe. In time (and use), the nails rvork loose or boards in contact with the ground decay, allorving the staircase to shift away and collapse.

Almost ahvays. collapses occur rvhen people are using the deck or stairs. As the critical connections become weaker, the motion of people on the deck creates inertia that causes the final pullout of the nailed connections. Unfortunately. this has devastating consequences to those on the deck. the homeorvner and the builder.

Dealers can do their part by encouraging use of screwed-in fasteners at critical junctures.

Lag bolts can provide up to nine times the pullout resistance of nails.

Ioal ]rcton

CBS News recently quoted deck experts who estimated that decks are separating from hornes at a rate of one per week. And, since docks are elevated structures, usually 8 to l2 ft. off the ground, injuries almost always occur. The primary causes ofdeck collapses include:

Age, especially of buildings erected before stricter structural requirements were instated in the late l980s

. Structural integrity-rot and decay

Loose or rusted bols and nails

. No inspections by a sturcnral engineer, a licensed private inspector, or a licensed general contrctor l-oose or spliting boards

Loose handrails

. Crowding (most decks are designed for a uniformly distributed live load of 4O lbs. per sq. ft) lrdger that is pulling away, splitting, or rocing

Through bolts, which are inserted through washers and a drilled hole and fitted with a nut on the other side, offer even greater resistance. Bolts also may loosen, but not as suddenly as nails.

Deck bracket systems can also hold decks' subframes together. When brackets are used, decks hold together to the limit of the timber strength, not just until the nails pull out.

The Decklok bracket system, for example, designed for new or existing construction, was engineered to address the three most critical connections on a deck: stair stringers, ledger boards and railing systems. Brackets anchoring ledger board to a house's floor joists provide up to 4,000 lbs. of resistance to deck pullout and subsequent collapse. For rail posts, Decklok creates a bolted connection, oriented-in shear, between the rail post and deck floor joist, increasing strength by 50OVo.

The brackets are constructed from l6-gauge steel and available with a post-manufactured hot dip galvanized

llecl $afety t[onth

To tackle the growing problem of unsafe decks, the North American Deck & Railing Association has designated May as Deck Safety Month.

Between August 2004 and December 2005, the U.S. media reported 225 injuries and one fatality caused by deck failures.

"No one has an estimate of total deaths and injuries per year, because most collapses are never reported in the media," said Frank coating for traditional deck applications and in stainless steel for use in seacoast applications.

Woeste, a deck-safety expert at Virginia Tech. In cooperation with the International Code Council, he helped created a deck inspection manual that can be purchased from NADRA.

"Each May, we will encourage homeowners to get an annual deck inspection," said Mike Beaudry, NADRA executive v.p. "We want to create an awareness of the risks of using a structurally deficient residential deck."

BRACKETS exponentially increase the strength of critical ledger board connections.

But. assuming proper construction in the first place, the best recourse for deckowners is proper maintenance and occasional inspections. Decks should be routinely checked for rot, decay, cracking, settling and grain severely opening. The ledger, rail and stairs should be inspected regularly for loose or missing connections. Make sure planking, support beams, handrails, and stair treads are not loose, cracking or failing. And also ensure that moisture is draining away from the deck.

During our almost 60 years in the redwood business, Big Creek has developed a reputation for being a reliable zupplier of high quality lumber. We produce a wide ranEe of grades and dimensions, custom cut timbers, pattern stock and fencing. Order full, mixed or partialtruckloads. Big Creek can provide FSC Certified redwood for green building proiects. i