Residential Stair Railing Landing Codes (2021 IRC Guide)

Do you want to learn about residential stair, railing, and landing codes?

Stairs are an important way to exit a home and to escape a hazard — such as a fire.

In this guide, I will go over...

  • Stairway code basics such as treads, risers, and guardrails
  • Common safety issues with stairs
  • Things home inspectors look for

Let's get started with this guide!

residential stair code

What Is The Residential Stair Code?

The residential stair code is a sub-section in the Means of Egress section of the International Residential Code handbook in Chapter 3 entitled Building Planning. 

Chapter 3: Building Planning  >>  Section 311: Means of Egress  >>  Sub-Section 311.7: Stairways

residential stair code

Technically, stairs are considered a 'means of egress' which basically means a way to escape from a home (or level of a home). The IRC is a model code standard that has been adopted by many U.S. states and some Caribbean and Latin American countries.

The International Residential Code is updated every 3 years, and the last update was in 2018. This guide isn't meant to go over every residential stair code detail in the IRC, but it is meant to present the basics and what I think is the most important.

Local Building Codes

Always remember that the staircase code of your state and county or city will almost always take precedence over the IRC unless the IRC has been totally adopted. Your state or county will likely have exceptions to the IRC standard as well.

IRC Staircase Code Exceptions

The International Residential Code standard has numerous exceptions to its residential stair code, and if any code in this articles doesn't fit what you are trying to do, I recommend consulting the IRC and your local code.

The IRC has exceptions to its code in almost every section in its stair code chapter.

Sometimes when we do a DIY job, such as building stairs, we spend a lot of time and money — and then end up hiring a pro to fix our mistakes. That's why I created my Contractor Search Tool, so my readers can get free quotes from local contractors who are licensed and pre-vetted. Get your free quotes with my contractor search tool right here.

Minimum Stair Width

The minimum stair width above the handrail and below the ceiling shouldn't be less than 36 inches.

One Handrail

Below the handrail, the minimum width should be at least 31.5 inches if there is one handrail.

Two Handrails

If there are handrails on both sides, then the minimum width of the rails should be at least 27-inches below the handrails.

stairway width residential stair code (1)


Headroom is the space required from the stairs to the top. Basically, this rule helps prevent people banging their head on ceilings and being a safety hazard.

This rule will more likely be an issue on older homes that I inspect, and they are usually grandfathered into existing code due to their age. I recently did a home inspection on an old home with numerous additions. The stairs to the basement had a ceiling protrusion that was probably around 5 feet and I repeatedly hit my head on the top. Ouch.

Minimum Headroom

The minimum headroom as measured from the stairs to the top should be at minimum 6-ft and 8-in. It is measured from the imaginary diagonal slope atop the stair risers or nosings.


This rule also applies to landings as measured from any area on the landing to the ceiling.

minimum headroom residential stair code

Vertical Rise

Vertical rise is the total height of the stairs as measured between floors or landings.

The maximum vertical rise of stairs according to the IRC shall be 151" or  about 12.5-feet.


Riser height should have a maximum height of 7-3/4 inch height. There shouldn't be a height difference of more than 3/8" between the tallest and shortest riser.

Open Risers

If the stairs has open risers, then anywhere above 30" from floor should not permit a sphere of 4-inch diameter to pass through. Basically, if there are no risers, then a child's head shouldn't be able to pass through above than 30" point from ground.


The treads (horizontal portions) of a stairs should be at minimum 10-inches. The longest tread versus the shortest tread shouldn't be more than 3/8-inch.

That basically sums of the basics of the stair tread code as well as risers

riser and tread length residential stair code

Read Also: Tips & Traps When Buying A Home


The stair nosing is the portion of the tread that sticks out beyond the riser. Stair nosings usually have a circular or beveled edge.

According to the IRC, the nosing shall have a minimum depth of 3/4" and a maximum depth of 1-1/4" depth.

Similar to the risers and treads, there shouldn't be more than a 3/8" difference between the length of the nosings.

Nosings are also not required if the stair treads are 11-inches or greater.


Landings are required at the top and bottom of stairs. One reason is that if there is a fall, you will only fall down the stairs a certain distance before hitting a landing.

Landings also make it easier to make turns onto a level or a different stair direction.

The width of the landing must not less than the width of the stairs.

Also, the horizontal slope of landings shouldn't be more than a 2% slope gradience.


Handrails are very important to home inspectors, and I have called out numerous stairs that are missing or have defective handrails.

The IRC states that if there are four or more risers, then handrails are required.

The stair railing height code in the IRC states that the minimum height is 34-inches and the maximum height is 38-inches. The top of the handrail is measured from the stair nosing, as if you drew a diagonal line across the top of the stairs.

Handrail Projection, Clearance, and Continuity

Handrails shall have a maximum projection from the wall of 4-1/2 inches. And there should be a minimum of 1-1/2 inches of clearance between the handrail and the wall.

The handrail also needs to be continuous from the top of the highest riser to the lowest riser.

The end of the handrail also needs to return to the wall, have newel posts, or safety terminals. Handrail termination is important so clothes or equipment doesn't get stuck on the end of the handrail, especially in emergency situations.

Handrail Grip Size

The handrail should have a minimum 1-1/4" diameter and a maximum 2" diameter if it is circular in shape.

If the handrail is not circular, it should have a minimum 4" perimeter (not diameter) and a maximum 6-1/4" perimeter. If the handrail is not circular and has more than a 6-1/4" perimeter, then graspable finger recesses should be provided on both sides of the rail.

handrail residential stair code 2
handrail residential stair code

What Do You Look For As A Home Inspector?

During my home inspections, the most common areas that I cite in regards to stairs come down to just a few items. 

And by the way, my favorite book on code is by DeWalt called Residential Construction Codes.

Residential Construction Codes is the complete guide to the 2018 residential building codes. It is highly readable and has great illustrations. It also includes those weird code exceptions that even code enforcers screw up.

You can view the price of Residential Construction Codes on Amazon right here.

1. Four Inch Sphere

Anywhere above 30-inches from the ground, there needs to be a guardrail to prevent a hazardous fall for an adult or child. In the home inspection world (and the IRC), there is a rule known as the four inch sphere rule.

Basically, it means that a 4-inch sphere should not be able to pass through the handrail. The 4-inch sphere is equivalent to the head size of a small child. If the child's head can get through, then their whole body can get through.

stair rail code safety four inch sphere rule

2. Loose Railing

Many times when I push on a railing, it is very loose. Most indoor stair handrails have a little give, but if it is obviously loose, I will call it out. For decks or hallways, the guardrail is more significant since numerous people may be leaning on the railing such as at a party.

3. Missing Railing

It never ceases to amaze me that a stairway can have a missing handrail, but it happens. Remember, any time you can fall more than 30" inches, there should be a guardrail.

4. Missing Lighting

Stairs should always have illumination for obvious reasons. If you are always going up and down stairs without lights, sooner or lighter you are going to take a fall. Stairs with more than six risers should always have a light switch at the top and bottom --- a three way switch.

Sometimes when we do a DIY job, such as building stairs, we spend a lot of time and money — and then end up hiring a pro to fix our mistakes. That's why I created my Contractor Search Tool, so my readers can get free quotes from local contractors who are licensed and pre-vetted.

I invite you to at least see the pricing for any home project from a few trusted contractors—there is no obligation—and then you can decide whether to go ahead with a DIY job. Get your free quotes with my contractor search tool right here.


There you have it, the basics of the IRC stair code. And again, the IRC is updated every three years, but usually the basic code remains the same. This guide isn't meant to present every single stair code --- there are NUMEROUS exceptions stated in the actual IRC stairway section. 

To really get the final word on any residential code, you should always go to the actual source such as the IRC website.

However, don't forget that state, county, or city codes may supersede the IRC.

Read Also: Venting A Bathroom Fan Into An Attic

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9 thoughts on “Residential Stair Railing Landing Codes (2021 IRC Guide)”

  1. What is the code for the placement of the Newell post(s) At the top of the stairs, relative to the floor level stair nosing?

    • Hey Noah,

      The IRC only mentions newel posts in one small area, “R311.7.8.4 Continuity” and describes that the railing has to terminate in either a newel post, returned to the wall, or a safety terminal — basically to prevent peoples clothing from getting caught on railing in case of fire/emergency.

      It never mentions nosing, only the riser.

      It states that the end of the railing (newel post) at minimum needs to terminate “directly above the top riser”.

      My homes top newel post actually overlaps the edge of nosing and the riser line. If at least part of the newel post is directly above the riser line, I think you are good to go.

      Good luck!

  2. I am installing a 2 round railing for my outside steps . If I dont hit a stud will the partical board be strong enought to support the railing and the people using it?

    • Hi Ardell,

      I don’t think such an installation would be to code. In section R301.5, its says that a “concentrated load applied in any direction at any point along the top” of 200 pounds per square foot for guards & handrails. I wouldn’t settle for an OSB wall connection.

      Good luck!

  3. Hi Arie,
    We recently constructed a small loft under the sloped ceiling of our living room. It’s about 6 feet off the ground, and the ceiling ranges from 26 inches – 36 inches above the floor of the loft. We were thinking of putting a ladder up against it and making it a hangout space for our kids. I’d put a railing up there for them of course, but I’m wondering about the minimum height of the railing since the ceiling is so low. (I’d prefer to keep it around 26 inches and not run the balusters up to the ceiling). I’m also wondering if there are any other code requirements to worry about with the ladder leading up to the loft. Or if you think an inspector would have an issue with this idea altogether! Thanks for your advice!

    • Hi Kelly,

      There would be a few code violations such as minimum ceiling height and minimum guard rail height. However, if you call that area a non-habitable storage area — it may exclude your from most of these codes to be honest. As home inspectors, we aren’t allowed to cite code violations in our home inspection reports, only government inspectors are allowed to call out code violations.

      Personally, I wouldn’t worry about it.

      Good luck!


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Arie Van Tuijl

Arie Van Tuijl

I am a licensed home inspector in two U.S. states and the founder of Home Inspector Secrets. After performing hundreds of inspections, and seeing thousands of house defects, I realized people would love to have an online resource dedicated to home maintenance. I write detailed home guides and product reviews sprinkled with inspection tips. You can read my bio here.

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Home Inspector Secrets is an online resource for owners, buyers, and sellers to understand all aspects of home maintenance. We have detailed home guides, product reviews, inspection advice, and much more.