Wood Deck Safety Check

Springtime is here! That means we’ll be looking around the house and making a priority list of spring-cleaning projects.  And, for many of us, giving our wood decks a good cleaning gets put at or near the top of the list.  That’s all well and good, however, we should take it a little further and put checking out how safe and secure are our wood decks, particularly those that are built several feet or more above grade.

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Ledger Boards

The ledger board is the board that is connected to the framing on the main house or to the brick veneer, as applicable.  Code requires this board to be fastened with lag bolts or with through-bolts and properly-sized washers.  Nails are not sufficient.  Failure of the fasteners in the ledger board and/or decay of the ledger board around its fasteners is one of the most common types of deck failure and it can be a sudden failure resulting in serious injury.  With the relatively new ACQ and CA chemicals used in pressure-treated lumber, one has three options for hardware:  G-185 hot-dipped galvanized, polymer-coated and stainless steel.  Stainless steel is the best and not-surprisingly, the most expensive.  If you use polymer-coated fasteners, check the package label for a listing of code-compliant.  Last, if the way that the ledger board is mounted interrupts the exterior finish material, make sure that the proper flashing has been installed and that it is in good condition.  This is necessary to prevent water intrusion through the building envelope.

Deck Rails and Stair Rails
Testing these rails for stability is pretty easy, but be careful to keep your balance on the walking surface during the test.  Just apply a medium amount of horizontal pressure at the top of the railing.  Secure railing may have just a slight amount of movement when pressure is first applied, but it should then stiffen and resist the applied-pressure if they are structurally sound.  The code requires that the guardrail resist a concentrated load of 200 pounds. It is critical to check these rails, particularly on highly-elevated decks.  Also, if one hasn’t ever checked the height of the railing to verify compliance with code, it’s a good idea to do so.  Residential rails are required to be 36” high and rails on commercial property are required to be 42” high.

The Rest of the Deck Sub-structuredeck 3_edited-1
It’s a good idea to put on some overalls or old clothes and either walk or crawl under the deck to check the connections of the joists to the ledger board, of the joists to the girders and of the girders to the posts.  A small gap between the members isn’t an automatic red flag as long as the nails are still straight.  If one can see that a joist has dropped down from being flush with the girder or can see that the connecting nails have begun to bend downward, these are urgently-needed repairs.  Once a nail starts to bend down, the connection can get very weak, very fast.

Electrical Items
It is not uncommon for the wiring that is run under residential wood decks to be exposed, i.e., not inside conduit. The wiring used in this application should have a UF marking, indicating special insulation that is rated for exterior use.  The electrical devices used outside are required to be NEMA-rated for exterior use.  It’s good policy to simply take a look and make sure that the insulation is not damaged and that no corrosion has occurred in or around the electrical devices.  Exterior receptacles need to be protected by a Ground Fault Circuit Interrupter (GFCI), either by using GFCI receptacles or a GFCI circuit breaker in the panelboard that protects the entire exterior circuit.  GFCI devices need to be tested regularly to confirm they are providing the needed protection.

Propane and Natural Gas Grills
Check for tight connections and for any corrosion on the gas piping and tubing. If you have a natural gas-fed grill, make sure that nothing in the deck structure has moved and added a weight load to the steel gas piping.  Also, make sure that the cutoff valve upstream of the grill is easy to open and close.  Last, but not least, make sure that you maintain proper clearance between the back of the grill and your house, especially if you have wood or vinyl siding.

Summary
If you desire further information, the North American Deck and Railing Association’s website is www.nadra.org.  Protect your family, friends and property and have a safe and enjoyable Spring and Summer.

Founded in 1997, The Warren Group, forensic engineers and consultants provides technical investigations and analysis of personal injury and property claims as well as expert testimony for insurance adjusters and attorneys. Extremely well versed in the disciplines of mechanical, electrical, chemical, structural, accident reconstruction and fire and explosion investigation, our engineers and consultants are known for delivering the truth — origin, cause, responsibility and cost of an event or claim — with unmistakable clarity.

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