Deck Railing Codes
All decks higher than 30" above grade must have a guardrail. If you choose to install a guardrail on a deck lower than 30", the railing must still meet code requirements. Decks attached to single family detached homes are generally regulated under the rules of the International Residential Code (IRC). The IRC requires guardrails to be at least 36" in height, measured from the deck surface to the top of the rail. Note that some local jurisdiction or state require higher, such as 42" in California. Commercial decks attached to multi-family buildings, such as apartment buildings or businesses, are regulated under the International Building Code (IBC). The IBC requires 42" high guardrails. In either case, you are allowed to build taller guardrails as long as they conform to all other requirements stated in the code.
A variety of styles are allowed as long as the interior sections of the rail don’t possess any openings large enough to pass a 4” diameter sphere through. In the case of guardrails for stairs, there is an exception that allows up to a 6” diameter sphere through the triangle opening formed by the stair riser, stairtread and bottom rail. The guardrails must be strong enough to withstand a concentrated 200 lb. force anywhere along the top of the rail.
There is also a safety factor required by the code, so testing loads are higher for manufactured railing systems. To achieve this, you should check to make sure you meet the post spacing requirements for the type of posts you are using and how they are attached to the deck. The sweep space between the deck surface and the bottom rail must be less than 4".
Handrails are required for stairs in many applications and must meet standards as specified by R311.5.6.3 in the IRC code. The top edge of the handrail must be placed between 34” and 38” above the nosing of the stair treads. Handrail ends must be returned and terminated at rail posts. The handgrips must allow a minimum of 1-1/2” space between the handrail and the guardrail or wall. A variety of gripping shapes may be acceptable but must meet requirements for the gripping surface. Flat 2x4 and 2x6 handrails do not meet the requirements for graspable handrails. If you are using a circular cross section, then the handrail must have an outside diameter of between 1-1/4” and 2”.
Engineered railing systems must be tested and certified to meet IRC and IBC building codes. The tests include:
- Infill Load Test: The strength of the balusters are tested so that a one-square foot area must resist 125 lbs. of force.
- Uniform Load Test (for IBC applications): The top rail must be able to sustain 125 lbs./foot length of force applied horizontally or vertically.
- Concentrated Load Test: The top rail must be capable of holding a point load of 500 lbs. of force applied to the mid span, on the side of a post and on top of a post.
A safety factor of 2.5 is included in the numbers listed above.
Glass Rails
Installing glass rails will usually require you to build the rail frame first and take precise measurements to custom order the tempered safety glass...
Installing Deck Stair Railings
Step-by-step instructions for how to install deck stair railings. Learn about the code requirements and construction tips with images.
Attaching Rail Posts
Step-by-step instructions for installing rail posts to your deck frame.
Deck Skirting and Fascia
Skirting can be an attractive feature that can be added to any low-level deck.
Best Under Deck Drainage Systems Reviews
An under deck drainage system creates a dry space under your deck and protects your substructure from moisture. Read our review of the best under deck drainage systems at Decks.com.
How to Build an Outdoor Table Yourself
Our DIY guide will show you how to build an outdoor table to entertain guests and make the most out of your deck or patio. Learn more with Decks.com.
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights
Deck Railing Codes
All decks higher than 30" above grade must have a guardrail. If you choose to install a guardrail on a deck lower than 30", the railing must still meet code requirements. Decks attached to single family detached homes are generally regulated under the rules of the International Residential Code (IRC). The IRC requires guardrails to be at least 36" in height, measured from the deck surface to the top of the rail. Note that some local jurisdiction or state require higher, such as 42" in California. Commercial decks attached to multi-family buildings, such as apartment buildings or businesses, are regulated under the International Building Code (IBC). The IBC requires 42" high guardrails. In either case, you are allowed to build taller guardrails as long as they conform to all other requirements stated in the code.
A variety of styles are allowed as long as the interior sections of the rail don’t possess any openings large enough to pass a 4” diameter sphere through. In the case of guardrails for stairs, there is an exception that allows up to a 6” diameter sphere through the triangle opening formed by the stair riser, stairtread and bottom rail. The guardrails must be strong enough to withstand a concentrated 200 lb. force anywhere along the top of the rail.
There is also a safety factor required by the code, so testing loads are higher for manufactured railing systems. To achieve this, you should check to make sure you meet the post spacing requirements for the type of posts you are using and how they are attached to the deck. The sweep space between the deck surface and the bottom rail must be less than 4".
Handrails are required for stairs in many applications and must meet standards as specified by R311.5.6.3 in the IRC code. The top edge of the handrail must be placed between 34” and 38” above the nosing of the stair treads. Handrail ends must be returned and terminated at rail posts. The handgrips must allow a minimum of 1-1/2” space between the handrail and the guardrail or wall. A variety of gripping shapes may be acceptable but must meet requirements for the gripping surface. Flat 2x4 and 2x6 handrails do not meet the requirements for graspable handrails. If you are using a circular cross section, then the handrail must have an outside diameter of between 1-1/4” and 2”.
Engineered railing systems must be tested and certified to meet IRC and IBC building codes. The tests include:
- Infill Load Test: The strength of the balusters are tested so that a one-square foot area must resist 125 lbs. of force.
- Uniform Load Test (for IBC applications): The top rail must be able to sustain 125 lbs./foot length of force applied horizontally or vertically.
- Concentrated Load Test: The top rail must be capable of holding a point load of 500 lbs. of force applied to the mid span, on the side of a post and on top of a post.
A safety factor of 2.5 is included in the numbers listed above.
Glass Rails
Installing glass rails will usually require you to build the rail frame first and take precise measurements to custom order the tempered safety glass...
Low-Maintenance Composite Deck Railing Options
Composite railing systems offer a low-maintenance alternative to traditional wood railings. Learn why composite is the best railing system at Decks.com.
Cable Rail
Cable rails are a modern looking rail system that preserves views. Learn how to install cable rails to meet building codes.
Deck Skirting and Fascia
Skirting can be an attractive feature that can be added to any low-level deck.
The Best Outdoor Rugs to Buy
Outdoor rugs are a great way to add additional style and protection to your deck or patio. Check out our recommendations for the best outdoor rugs.
Trex Composite Decking Reviews [current_year]
Trex’s low maintenance composite decking resists fading and does not rot or warp. Read our review for the Trex Transcend, Enhance and Select boards.
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights