36 inches (91 cm) from the deck surface to the top of the railing is the minimum required height for decks in most states and countries. However, the IBC (International Building Code) requires a railing height of 42 inches (107 cm). Several states model their building codes off the IBC requirements. For instance, California requires deck railings to be 42 inches tall. So, while 36 inches is the bare minimum in most locations, 42 inches is accepted globally as a safe height for your deck railing.
Table of Contents
How High Can Your Deck Be Before You Need a Railing?
If your deck is more than 30 inches (76 cm) above the surrounding area, it legally requires a railing. Even if your deck is less than 30 inches above its surroundings, it’s often best to have a railing 36 or 42 inches tall (91–107 cm). This will prevent any accidental slips and falls that could be harmful to you or your family.
- Decks that stand more than 30 inches (76 cm) above the ground legally require a railing.
- If your deck is less than 30 inches above its surroundings, no railing is required.
- For safety, it’s best to install a railing on any deck more than 7 inches (18 cm) above the ground.
It’s generally recommended that if you need stairs to climb from the ground to your deck, it needs a railing. Since individual stairs in the United States are 7–8 inches tall (18–20 cm), it’s best to install a railing on your deck if it is more than 7 inches higher than its surroundings.
What Height Should Deck Stair Railing Be?
International Building Code requirements state that deck stair railing must be between 34 and 38 inches tall (86–97 cm). Although stair rails are slanted, this number is determined by measuring straight up from the nose of the stair tread to the top of the handrail.
How Far Apart Should Deck Railing Spindles Be?
The vertical guards of the deck railing—sometimes called spindles or balusters—should be no more than 4 inches (10 cm) apart. It is acceptable to reduce the gap between the vertical guards to be less than 4 inches, but it is never acceptable to place them more than 4 inches apart. This width is designed to prevent children and animals from getting stuck between the railings.
How Far Should the Lower Railing Be From Your Deck?
If you are installing a deck with a horizontal railing that leaves a gap between the lower edge of the railing and the deck itself, this gap cannot be larger than 4 inches (10 cm). Again, you can make this gap smaller than 4 inches, but it cannot exceed this distance. We advise constructing your deck with a 4-inch gap between the lower edge of the railing and the deck. This allows you to easily sweep leaves and other debris off your deck.
What is the Building Code for Deck Post Spacing?
Deck support posts must be placed no more than 8 feet apart (2.4 meters). Any more than this distance undermines the structural integrity of your deck guardrail. As with previous examples, you can plan your deck frame with posts closer than 8 feet, but the distance between posts cannot be greater than 8 feet.
What is the Best Height for Deck Railing?
The best height for your deck guardrail is 36–42 inches (91–107 cm). This distance is measured from the deck surface to the top of the railing. 36 inches meets the requirements for most residential decks. However, for commercial decks, or decks built in California, 42 inches is the minimum height to get approval from your local building department. Some important deck planning numbers to keep in mind are:
- Railing Height: 36–42 inches (91–107 cm)
- Maximum Deck Height Before Railing is Required: 30 inches (76 cm)
- Deck Stair Railing Height: 34–38 inches (86–97 cm)
- Maximum Distance Between Deck Guardrails: 4 inches (10 cm)
- Maximum Distance Between Deck and Lower Guardrail: 4 inches (10 cm)
- Maximum Distance Between Deck Posts: 8 feet (2.4 meters)
When you are planning your deck and submitting plans in order to obtain a building permit, incorporate these measurements. Meeting building code requirements keeps you and your family safe. It also makes sure your new deck guardrail passes an examination by a building inspector.
