US Building Codes for Wood Decks

Posted on Posted in Deck Safety

A deck is a lovely addition to any home. Aside from adding an outdoor living area, it also raises the value of your home. A deck that’s improperly constructed though can be dangerous. The International Residential Code (IRC) has set out requirements for deck construction and design. Local codes may also vary but those are based on the IRC requirements.


Some of the IRC requirements for deck construction and design are:


A deck must be designed to support a dead load of 15 pounds per square foot and a live load of 40 pounds per square foot. A dead load is the weight of the deck structure itself plus the weight of any permanently attached elements on the deck. The live load is the weight of anything that will be on the deck temporarily such as people and furniture.


Lumber used in the construction of the deck must be treated so that it is resistant to decay, and any structural element that comes in contact with the ground must be built with lumber that is specifically rated as approved for ground contact.


All fasteners, including screws, nails and bolts, used in the construction of the deck and in connections between the deck and the existing structure must be zinc-coated galvanized steel or stainless steel in order to be resistant to corrosion.


Guardrails are required wherever the deck is 30 inches or more above the surrounding grade. Guardrails on residential decks must be at least 36 inches high; the railing must also be filled in with vertical balusters, and the balusters can’t be more than four inches apart. Stair handrails are required on any set of stairs with four or more risers; the handrails must be between 34 and 38 inches above the stair treads and have a diameter of between 1 1/4 and 2 5/8 inches. Stairs more than 30 inches above grade must also have a guardrail.


Not sure if your deck adheres to the IRC requirements? Call Westside Company at 310 994 4626 or e-mail us at for more information about professional deck inspections and make sure your deck is up to standards. We serve Los Angeles and the surrounding areas.