Accessory dwelling units are going up all over Southern California, from Riverside and the Inland Empire to Ventura County. More of them are two stories, sit over a garage or have a raised deck, and that means railings. Here’s what homeowners building an ADU should know before the framing goes up.
Where ADUs need railings
- Exterior stairs to a second-floor ADU or a unit over the garage
- Landings and balconies outside an upper-level door
- Raised porches and decks more than 30 inches above the ground
- Ramps for accessible ADUs designed for aging parents
The code in short
The same rules apply to an ADU as to any home: guards at least 42 inches tall, openings that a 4-inch sphere can’t pass through, and stair handrails 34 to 38 inches high. Our California railing code guide explains each rule.
Choosing a style
An ADU railing should look like it belongs with the main house:
- Spanish or Mission homes: black wrought iron with simple pickets or scrolls. See wrought iron railings.
- Modern ADUs: horizontal cable railings or glass on an upper deck
- Budget-friendly and low maintenance: powder-coated aluminum. Our wrought iron vs. aluminum guide compares the two.
Plan railings with your ADU builder
The best time to choose railings is during design, not after drywall. Ask your builder to show the guards and handrails on the permit plans and include them in the estimate, and have the framer add solid blocking where the posts land.
If you’re still early in the process, Oxnard ADU Builders has a helpful guide on how long it takes to build an ADU, from design and permits through construction. Most of the timeline applies to any California city.
Ready to price railings for your ADU’s stairs, deck or balcony? Request a free quote from a local Riverside fabricator.
Common questions
Can I add railings after my ADU is built?
You can, but guards and handrails are part of the final inspection when the ADU has stairs, decks or landings more than 30 inches up, so they usually have to be in place before the city signs off. Planning them early also lets the framer add blocking for strong posts.
What railing is best for an ADU staircase?
Powder-coated steel or aluminum pickets are the most common choice for exterior ADU stairs because they're durable, low maintenance and easy to match to the main house. Cable and glass work well on upper decks and balconies with a view.
Do ADU railings follow the same code as the main house?
Yes. The same California Residential Code rules apply, including 42-inch guards, the 4-inch sphere rule and 34 to 38-inch handrails.