The standards of the building code for outside decking railings and stairways are particularly strict since correctly constructed decks can prevent major injuries. The Consumer Product Safety Commission projected that the breakdown or collapse of decks and balconies caused 2,900 injuries between 2016 and 2019. Deck building code regulations are always evolving, therefore it is essential to stay up-to-date on the latest requirements.
For instance, your older deck may have toe-nailed connections, which are wood connectors created with nails hammered at an angle through the joints. If so, be advised that according to the current International Building Code, toenailing is no longer a valid connection (IBC). Earlier decks built with older methods may be grandfathered in, but new requirements must be satisfied. When constructing a new deck or remodeling or repairing an older one.
Deck Code Terminology
As a model code, the International Building Code (IBC) is created by the International Code Council for governments and cities. The other local organizations to adopt and modify for their own usage. Consequently, your municipality can modify the IBC to meet the demands of its inhabitants. Before building, be sure to contact your local permit office and examine the applicable code.
Understanding the IBC code requirements is easier if you are familiar with the following terminology:
- Guardrails: A guardrail (sometimes referred to as a guard) runs horizontally along a landing or other flat place with a drop on the opposite side. As specified by the code, a guardrail is distinct from a railing, which is a comparable component used on stairways.
- Railing: As defined by the building code, a railing is a sort of protection for steps that run along the stairway’s incline.
- Balusters: Balusters are short vertical infill posts that run between the guardrail or railing to prevent anyone, especially children, from slipping from the deck via the opening beneath an inclined stairway railing or a horizontal guardrail.
- Grade: Grade is the ground level immediately adjacent to the deck.
- Low-rise decks: Low-rise decks, also known as ground-level or floating decks, do not exceed 30 inches in height above the ground and are therefore free from certain guardrail and baluster standards. Additionally, most low-rise decks do not require a building permit.
- Rise: Rise is the vertical distance between each stair tread.
- Tread: The tread is the flat portion of a staircase where one places their foot.
Deck Guardrail Height
Deck guardrails should extend at least 36 inches above the level of the residential deck. This is the minimum height necessary for residential structures; taller guards are permissible. The minimum height for commercial deck guardrails, such as those found in restaurants, bars, and multifamily dwellings such as apartments and condominiums, is 42 inches.
When Is a Deck Guardrail Not Needed?
Some decks are exempt from guardrail requirements if they are no more than 30 inches above grade. If you observe a deck without guardrails (also known as a low-rise deck). Its height of fewer than 30 inches may be the cause.
Guardrails on Low-Rise Decks
Even on short, low-rise decks, numerous homeowners elect to install guardrails.
If you want to install a guardrail on a low deck, its height and baluster spacing are up to you. Nonetheless, these railings must be as sturdy as those on higher decks. It is expected that people will lean against guardrails, and the law demands that these guardrails be able to withstand collapse.
Adding handrails to a low-rise deck is frequently an excellent idea. Including guardrails on low-rise, decks are beneficial for disabled individuals.
Requirements for Deck Stairs
The IBC code for structural design specifies stringent criteria for deck stairways:
- Measuring vertically from the nose of the tread to the top of the rail, stair rails on decks should be between 34 and 38 inches in height.
- The depth of treads must be at least 10 inches from front to back.
- The treads of stairs must support at least 300 pounds over an area no larger than four inches square.
- The rise, or vertical distance between treads, must not exceed 7 1/4 inches.
Deck Balusters and Benches
Deck balusters must be spaced no more than four inches apart. A classic rule of thumb is that a ball with a 4-inch diameter should just barely fit between the balusters. This 4-inch spacing is the usual diameter of a baby’s head to avoid their heads from becoming trapped.
Where balusters meet a lower railing, the distance between the bottom of the railing. The deck surface shall not exceed four inches.
Deck benches: Homeowners who are concerned with preserving the view from their decks may question if benches are suitable alternatives to deck guardrails. Unfortunately, benches are not a suitable substitute. On deck builds tall enough to necessitate guardrails, they must still be built behind benches, rising at least 36 inches above the surface of the decking.
Minimum Strength for Guardrails and Balusters
Guardrail strength requirements: The International Building Code stipulates that guardrails must be able to withstand a 200-pound force without undue deflection at the midspan between posts.
Requirements for baluster strength: balusters and infill rails must withstand a minimum of 50 pounds of concentrated testing force.
Building inspectors typically measure the strength of guardrails and balusters by leaning or pushing against the components. In commercial applications, this can be performed by a third-party testing organization with equipment capable of applying up to 500 pounds of force.