Deck Safety

By Robert Robillard on Decks And Porches

Deck SafetyDeck Safety Retrofit Steps:


Wood can rot over time or when over exposed to moisture like a lawn sprinkler.  Inspect and replace all rotted framing, decking or railings as needed. Large cracks in framing should also be evaluated and replaced.
Declk post

Missing or Improper Connections:

Toe-nailing or direct nailing of joists is no longer an acceptable way to secure joists with out additional metal connectors added.   Assuming you’re using the correct sized floor  joists for your span, the addition of corrosion resistant or stainless steel joist hangers or hurricane ties is an easy way to make your deck flooring system stronger, safer and in compliance with International Building Code [IBC] and International Residential code. [IRC]

Follow the metal connector manufacturer’s recommendations for fastening any metal connector in your deck safety retrofit.  My general rule of thumb is to use 16D galvanized nails everywhere I can.

Deck Safety

Loose Railings, Stairs, Ledgers or Support Posts:

Decks degrade over time, wood expands and contracts, fasteners can rust or come loose over time and make a potentially dangerous situation. Adding additional support to loose railings or ledgers can easily be accomplished by using ¼” diameter Structural screws or thru-bolts to secure the deck from vertical loads.  See VIDEO on Lateral Tension Device.

Deck Safety

Thru-bolts should be a diameter of ½” installed through 17/32 to 9/16” pilot holes and have washers at the bolt head and the nut.  I like the structural screws because they do not require pre-drilling, are corrosion resistant and designed to be used with pressure treated lumber.   Follow manufacturers’ recommendations for fastener length and placement.

Deck Safety

Deck ledgers should also have a minimum of two galvanized or stainless steel lateral load connectors [tension ties] connecting the deck joist to the house floor system.  [photo right] Each device should have an allowable stress design capacity of not less than 1,500 lbs.    I use Simpson’s tension tie # DTT2z on my deck in stalls and retrofits.  These connectors tie the deck in to the hose and protect against lateral loads resulting from wind, seismic or people on the deck.

Loose deck support posts should be replaced and the deck frame should be checked to make sure it is still level and the footings have not sunk.   Posts should be 4×4 or preferably larger and made from pressure treated material. Post to beam galvanized or stainless steel connecters should be used.

Inspect Metal Components for Corrosion:

Fasteners and connectors can corrode over time.  Inspect your deck fasteners and connectors for this as well to see if the proper fasteners were used. For example, many ties people will install joist hangers but then use improper nails to install them.  People often install the wrong size joist hanger.

Joist hangers must meet IBC and IRC code of downward capacity.   You can determine this by using an approved manufacturer’s product data based on the dimensions of your joist or header that you are carrying.

Use the recommended nails and fasteners for the metal connector you’re installing.  Roofing, screws and box nails have no place in any metal connector fastening system and should be replaced and avoided at all costs. Also make sure to install a properly sized nail or fastener into every metal connector hole provided.

Support Posts:

Deck support posts should be mechanically fastened both to the footing in the ground and the deck frame or beam. You want to ensure that your deck support posts resist lateral and up lift movement.

Deck Safety

If your posts are notched to hold a beam they should be a minimum of 6×6 [nominal] and have a corrosion resistant post to footing and post to beam connector.  There are a few retrofit options available to accomplish the post to beam.    These connections are needed to resist lateral ad uplift loads.

Replacing the post usually means temporarily supporting the deck and then adding proper metal base connectors.   For retrofitting a metal connector into a proper footing you can drill a hole and use a mechanical wedge anchor or epoxy an anchor in place.

Deck Safety

Adding diagonal bracing to both the parallel and perpendicular side of the deck post is also a good ideal to reduce lateral motion and racking of the deck.  Diagonal braces should be installed at a 45 degree angle 24” down from the beam and 24” out from the post.

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About the author

Robert Robillard

Carpenter / Remodeler / Editor

Rob Robillard is “The Concord Carpenter” Rob is a builder, general contractor, carpenter, woodworker, and editor of Concord Carpenter and ToolBoxBuzz As a General Contractor and carpenter, Rob owns and operates Concord Carpenter LLC. A full-service remodeling and construction company. Rob is a recognized leader in home building best practices and a source for how-to information for building professionals. On this website, Rob covers all aspects of home construction, building science, home improvement, woodworking, remodeling, and some of the best product and tool reviews. Rob is in charge of our Tool and Product Review series - Concord Carpenter Videos where we post all of our tool reviews and video tutorials. Rob approaches remodeling and building construction with a pragmatic and problem-solving approach. He enjoys using his knowledge and experience to help and educate building professionals as well as DIYers on best practices in the construction and remodeling industry. He's a strong advocate for "raising the bar" in the construction trades and promoting the trades to youth. #BeAMentor #Green2Great Craftsmanship, quality, and pride guide his journey on this channel The Concord Carpenter's motto: "Well done is better than well said!" : Read more about Rob

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