Am I right? The IRC has no minimum rise height for stairways???

(Nick Gromicko, CMI) #1

We made it 4" in because a low rise height is a trip/fall hazard (people don't see it as a step).

(Jeffrey R. Pope, CMI) #2

You are correct. No minimum rise (R311.5.3.1). A 0" rise would be a ramp :D

(Nick Gromicko, CMI) #3

Short rises are a serious hazard on stairs, people don't recognize them as a step coming down. I've seen some treads intentionally carpeted with very different colors to alert people of a low rises.

(Nick Gromicko, CMI) #4

I should have looked at my morning emails first:

*Dear Mr. Gromicko:

Re: Minimum riser height of the 2006 IRC

Unlike the 2006 IBC, which has a 4 inch minimum riser height (Section
1009.3, IBC/06), the 2006 IRC does not have any such requirement.

This opinion is based on the information which you have provided. We
have made no independent effort to verify the accuracy of this
information nor have we conducted a review beyond the scope of your
question. As this opinion is only advisory, the final decision is the
responsibility of the designated authority charged with the
administration and enforcement of this code.


John S. Gonzalez
Technical Staff
Chicago Dist. Office*

(Michael Larson, WI Lic. # 1672-106) #5

I would say that depends on the tread depth. It's not really a problem as long as one can descend reasonably comfortably.

(Robert D. Grizzle, Jr.) #6

I looked it up in the IRC Commentary and it states
"This code establishes that the maximum riser height is 7-3/4 inches. the IRC does not state a minimum riser height as does the IBC, where 4-inch limit is specified."

(Emmanuel J. Scanlan, TREC# 7593) #7

As Jeff stated the IRC code itself does not specify a minimum height.

2003 IRC:

311.5.3.1 Riser height.
The maximum riser height shall be 7 3/4 inches (196 mm). The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm).

However the IRC does reference and use the following ANSI standard for minimum riser height. ANSI A117.1-1998

504.2 Treads and Risers.
All steps on a flight of stairs shall have uniform riser heights and uniform tread depth. Risers shall be 4 inches (100 mm) high minimum and 7 inches (180 mm) maximum. Treads shall be 11 inches (280 mm) deep minimum, measured from riser to riser.

So your minimum riser height is justified by at least one accepted, and major, standard.

(Nick Gromicko, CMI) #8

Good then, we're sticking with 4".

We're eventually going to come up with a stairway add-on to

(John Bowman, Executive Director) #9

I believe the UBC addresses it. This may help.

(Nick Gromicko, CMI) #10

Thanks John. The author of that article is going to review our document.

(John Bowman, Executive Director) #11

Here is some more info for you out of the ADAAG.

<H4>Treads and Risers [4.9.2], Nosings [4.9.3]**

Treads must be at least 11 inches wide and uniform. Uniformity is important not only between steps but along each step; curved stairs, where the width of each tread varies, do not meet this requirement. Variation in riser height along a set of stairs can be a tripping hazard. ADAAG requires the height to be uniform but does not specify a minimum or maximum height which is addressed by most local building codes. (The CABO/ANSI A117.1-1992 standard requires a riser height between 4 to 7 inches.)
People without full use of a leg may drag a foot when ascending stairs. A smooth transition from tread to tread is essential. Open risers and abrupt or extended nosings (i.e., projecting more than 1 ½ inches) can catch the toe. Angled or rounded nosings or sloped risers help prevent this hazard and provide a smoother transition. Straight risers without nosings are acceptable. ADAAG specifies the radius of the curvature of the leading edge of treads and the underside slope of angled or rounded nosings.


(Bob Elliott, 450.0002662) #12

Hmmm, I think back to all the natural stone or slate steps with extremly wide treads and have no recollection of tripping , unlike if it was unexpected at an indoor setting.
I think one should take the surroundings into account when reporting.

(Barry Adair, TREC#4563 EIFSTX#39) #13

many issues on this upscale over $1M condo

client busted his nose during the inspection coming out of the kitchen onto the angled landing

(Kenneth Lott, 001236461) #14

Nick, I agree some of these stepdowns are dangerous, there needs to be a way to make them at least visible, especially in dark areas. Since I'm just offering opinions on my observations, I always mention them in my reports as possible trip hazards. If it kills the deal, then there never was much of one anyway. IMO

(Nick Gromicko, CMI) #15


(homebild) #16

You are correct that the IRC does not have any maximum riser height, but your change to require a 4" minimum is not legally enforceable...particularly in your home state of Pennsylvania.

The Pennsylvania Uniform Construction Code has amended section R311.5.3.1 of the International Residential Code and replaced it with exception 8 to section 1014.6 of the 1992 BOCA National Building Code and additional provisions of the 1992 CABO One and Two Family Dwelling Code namely:

Pennsylvania Uniform Construction Code Section 403.21 (6)(ii):


(ii) The following specifications apply to residential stairway treads and risers.(A) The maximum riser height is 8¼ inches. There may be no more than a 3/8 inch variation in riser height within a flight of stairs. The riser height is to be measured vertically between leading edges of the adjacent treads.* *
**(B) The minimum tread depth is 9 inches measured from tread nosing to tread nosing. **

**(C) The greatest tread depth within any flight of stairs may not exceed the smallest by more than 3/8 inch. **

**(D)Treads may have a uniform projection of not more than 1½ inches when solid risers are used. **

**(E) Stairways may not be less than 3 feet in clear width and clear headroom of 6 feet 8 inches shall be maintained for the entire run of the stair. **

(F) Handrails may project from each side of a stairway a distance of 3½ inches into the required width of the stair.


The Pennsylvania Uniform Construction Code **prohibits BY LAW *it's stair geometry regulations from being made stricter by local amendment and *prohibits BY LAW **previously enacted local codes which required stricter geometry for stairs from being continued or enforced....including riser height minimums.

While a 4" riser minimum might seem like a 'good idea', there does not appear to be any empirical evidence to support claims for such a minimum.

As mentioned, safe stairway construction does not preclude risers being less than 4" high, provided the ratio of riser height/tread depth is kept within the limits of a normal human walking 'pace', or about 17-18".

(homebild) #17

"However the IRC does reference and use the following ANSI standard for minimum riser height. ANSI A117.1-1998?

This statement is completely false.

The 2000-2006 International Residential Code does not reference ANY 'ANSI' standards regarding stairway geometry or riser heights.

Requiring a 4" minimum riser height is completely arbitrary and without merit.

(Erby Crofutt) #18

Ben & Nick:

Ben said in another post

That's a good document. Boring. But good.

It doesn't come close to the information presented by Paige.

Recommend printing out and reading the companion checklist and stairway narratives while viewing

Your are right. It is a good document.

You're right. Doesn't come close. But I can't carry Paige to the inspection in my pocket or briefcase. (Bummer) Good source, but no quick referral method.

Where are the links to the companion checklist and stairway narratives? Can you provide a link to all appropriate documents on the video page? That would be a big plus!

The main reason I use the Stairway Manufacturer's Document is to give to builders who want to argue with me about interpretation. When I give them that, they usually just shut up and fix it.

(Richard A. Hetzel) #19

When will people realize that the building code is not a design textbook? Stair proportions should be given by the designer, and there are several rules-of-thumb for determining proper stair proportions. It is the designer's obligation to know which one to use and how to apply it properly. If it left to the builder, the result may or may not be good, even if it meets code.

The most frequently used is Tread + Riser = 17 to 17 1/2 inches. Also used is Tread times Riser = 70 to 75 inches. There are others. However, when the riser is less than about 6 inches, it is sometimes best to elongate the tread dimension, especially on exterior steps. There is some professional judgement involved.

(Emmanuel J. Scanlan, TREC# 7593) #20

"However the IRC does reference and use the following ANSI standard for minimum riser height. ANSI A117.1-1998?

This statement is completely false.

The 2000-2006 International Residential Code does not reference ANY 'ANSI' standards regarding stairway geometry or riser heights.

Requiring a 4" minimum riser height is completely arbitrary and without merit.

Wow! Looks like somebody got up on the wrong side of the bed this morning!

Actually we are both wrong and both right. Yes, the IRC does not have a specific, printed reference to ANSI A117.1-1998. However the IRC was intended to cover 1 - 4 family dwellings. The IRC concerns itself with accessibility issues (which is what this ANSI standard is about) in a structure with 4 or more dwelling units:

[QUOTE] R322 ACCESSIBILITY 322.1 Scope. Where there are four or more dwelling units or sleeping units in a single structure, the provisions of Chapter 11 of the International Building Code for Group R-3 shall apply.

Now if you follow that to the IBC:

1101.1 Scope.
The provisions of this chapter shall control the design and construction of facilities for accessibility to physically disabled persons.
1101.2 Design.
Buildings and facilities shall be designed and constructed to be accessible in accordance with this code and ICC A117.1.

So as you can see the IRC does reference the ANSI standard, but again not directly printing the number in the IRC.

I am curious though about your profile. You state you are a "Homebuilder" and a "Building Code Official" in PA. As a proclaimed "Authority Having Jurisdiction" ( see post reference below) why do you feel the need to hide beyond the moniker of "homebild"? Why do you not provide your name and jurisdiction and assume a true authoritative role? Are you here to educate or berate?


As an Authority Having Jurisidcation and an Energy Code Inspector, I can speak with authority that your original post was misleading and wrong and did more harm that help the discussion....and hence the need for correction.

Whether a Code Department is large or small has no bearing on the fact that the Authority Having Jurisdication and the Energy Code Inspector are completely different entities serving different functions.

There is also no correlation between the size of a Code Department and whether or not the functions of Authority Having Jurisdication and Energy Code Inspector are performed by the same or separate individuals. In many small code departments, the AHJ and Code Inspector are still not synonymous.

The fact remains, your information regarding the purpose, means and intent by which certificates of energy compliance are required to be installed, was not true under any circumstance, and your continued attempt to justify your errors only continues to serve to confuse this issue and thread.

If you wish to further confuse others and demonstrate your ignorance on the subject, please continue to post...