Saturday, 11 December 2010

Poor Deck and Stair Construction Can Kill

In a recent article published in The Los Angeles Times, July 6th of this year, a tragic deck collapse resulting in serious injury and death, is reported. The deck was part of a three story apartment complex in a Birmingham suburb. Seven party-goers is all it took to create this tragic event. Unfortunately, this is an all to common occurrence now days. Reports are continually surfacing, confirming the growing frequency of these serious, life threatening collapses.

Over the past several years, much has been done to address deck and stair safety issues, but we still have a long way to go. One glaring example of the failure in deck and stair safety protocol is the industry standard of permitting "hot dipped galvanized" anchors, screws, hangers and other hardware to be in direct contact with ACQ, pressure treated wood. The galvanic corrosion created between the high copper content of the wood and the galvanizing is so severe that the normal industry standard of G90 galvanizing will corrode in as little as 12 months and G185, such as Z-Max® can be gone in 24 months. The industry (including code officials) has adopted G185 as a fall back position with no engineering testing available to substantiate the validity or longevity of this adoption...this is a "knee jerk" reaction and is an accident waiting to happen. Without a barrier between the pressure treated wood and galvanized hardware, serious corrosion is inevitable.

Take for example the new NADRA (North American Deck and Railing Association) study that examined the number of injuries caused by outdoor deck stairs and porches from 2003 to 2007. The report confirms that deck and stair injuries are on the increase. NADRA points to a 2003 study showing a total of 37,760 injuries which required a visit to the hospital. Of these injuries, 6,120 were a result of structural failure or collapse. Further, the report shows that by 2007, the incidents of serious injury had risen to 55,160. Quoting from the report- "Nearly 15% of all injuries are a result of structural failure". Wood decks are constantly exposed to the elements and they have a limited life span of 10-15 years. As you can see, important to have your deck and deck stairs inspected so that signs of wood decay and deterioration can be repaired.

Other codes address "rail post support" safety. A rail post per code regulations is required to support a lateral load of 200 lbs. This is a poorly enforced area of the code and with many inspectors content with the bump test. If it doesn't move too much when they bump it with their hip, the rail will pass inspection. Many rail posts are simply lagged or nailed to the rim joists and post which are mounted directly to the deck surface will simply not meet code. The tragedy is, there are systems available on the market that correctly address this problem. Simpson, USP and Deck-Loc have brackets which will meet code for rim joist attachment but there's only one adjustable bracket system (discussed below) which will meet code for wood or composite stairs.

Attention is now being given to the ability of the vertical post's strength when hit by various degrees of lateral thrust pressure. These new directives, requiring the vertical rail post to support a minimum of 200 lbs. of lateral thrust, is making engineered stair systems extremely popular, with their ability to withstand over 500 lbs of lateral thrust for the 'rail post support' structural sections of the overall decking plans.

Stairs are perhaps the most overlooked area of construction. Stairs using standard cut stringers have been used for eons and are "grandfathered" into code as accepted construction. Stringers are cut from 2x12's and greatly weakened in the process. Several stringers are then run longitudinal down length of the stair to make up for the strength loss during cutting. Long stair run tend to bounce and stringer failure is not uncommon. Additionally, many of these stairs are built without risers which is a "child safety" issue in many states. General Contractor and renowned professional deck builder, Pat Noonan of Minnesota says, "Of the 50+ decks I have torn off and replaced, not one had a stair system that outlasted the deck." The majority of them had shaky, unsafe stairs, and it was the main reason they were doing the rest of the deck."

Engineered stair systems such as adjustable bracket systems for wood stair and composite stairs overcome many of these problems and safety issues. This is due to the much more rigorous testing required to gain ICC/ES acceptance for a stair system which has not been simply "grand fathered" into common use. This adjustable bracket system is engineered in a completely different manner to conventional stair construction. These adjustable steel brackets lock the risers and treads onto the stringers, with a solid, joist hanger type connection. Only two stringers are required for stairs up to 7' in width. This becomes possible because the two outside stringers are full depth, acting like beams running down the length of the stair ( only three end are cuts required per stringer). Next, the risers (which are locked to the steel brackets) span across the stair like joist hangers, at each step supporting the tread.

The result is a "rock solid" stair which has been tested at over 1,200 lbs. per sq. ft.(uniform distributed load), well in excess of the code requirement of only 100 lbs per sq. ft. (commercial load). The steel brackets adjust to form any rise or run required and are powder coated over a hot dipped galvanized finish. The powder coating (paint) sets up an effective barrier between the pressure treated wood and the galvanized finish, preventing corrosion. Additionally the structural risers overcome the child safety issue (found on stairs without risers) and as mentioned above, the brackets have been tested to exceed code requirements for lateral load applied to "rail post" supports.

General Contractor Pat Noonan continues, "Craftsmanship will only take you so far when you are dealing with a inferior framing system and components. When deck builders notch steps out of a 2"x12", they are cutting all the strength out of the wood and putting the entire weight of the stair plus anyone walking up or down on 4" of wood left in the 2"x12". With an adjustable bracket system, they are putting the weight on 11' of solid wood- there's no comparison".

EZ Stairs adjustable bracket stair system allows builders to construct stairs with a wide range of materials such as redwood, cedar, tropical wood, treated wood, untreated wood, vinyl, steel, and composites. This stair system allows for customized rise and treads configurations which can be adjusted to meet all building codes for any interior or exterior application- ICC approved. It is the only adjustable stair bracket system available anywhere. The EZ Stairs system will allow you to build strong, easy to install stairs, in less time and with less money than traditional construction. You will have stairs that will last for many years longer than conventional stair construction.To help you figure out how many stairs you will need, the website provides a free stair calculator.

Tag : stair lifts,stair desigh,stair railing

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