PHOTO 7. They use the term “tread” instead of “run” but I think that’s the cause of some confusion, so I’ll use the standard term “run.”. The Perfect Stair (in my opinion): If it meets only one of the numbers, it will be less comfortable. Riser Height and Tread Depth (IBC 1011.5) The step height, also known as the riser height, must be no less than 4 inches and no greater than 7 inches. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3⁄8 inch (9.5 mm). Molasseskat commented with a good idea; here is a graph that shows what I consider the “sweet spot” for stair design. 2r+R = 25 1/2" (within range) Forming Part of Sentences 9.8.4.1. It may be a little busy but the yellow area represents a stair that most people will find comfortable. It turns out it's not a circle but a parallelogram, at least using my rules of thumb. Riser height shall be from 6 to 7.5 inches (15.24 to 19.05 cm), stair width a minimum of 22 inches (55.88 cm) between vertical barriers, tread depth a minimum of 12±2 inches (30.48±5.08 cm), and tread nosing shall be straight leading edges. rise r = 7 3/4" The minimum depth, measured in the direction of travel, is 36 inches. The maximum riser height shall be 7 3/4 inches (196 mm). 2. A nosing is not required where the tread depth is 11 inches. International Building Code for Stair treads and risers 1009.3 Stair treads and risers. The maximum width of a public staircase is 1800mm. I call it a lazy stair, because it seems to take no effort to use (but you still feel like you’re getting somewhere). If you want to pass spiral staircase building regulations, for example, you will have more homework to do. On my first stair, r+R was roughly 15 inches—way too far from 18” to be comfortable or safe. Lee has over two decades of hands-on experience remodeling, fixing, and improving homes, and has been providing home improvement advice for over 12 years. The value for the Actual Riser Height property changes to accommodate the stair height change. Outside of the yellow zone represents a stair that most people will find uncomfortable in some way. 2r+R = 22" (too low) The maximum of 18 risers in a flight. STAIR WIDTH. Molasseskat, I'm sorry I missed your comment (six months ago!) In any case, the local code is what you must follow to pass inspections. A stair riser is the back, vertical part of a step. Keep in mind, your local building department may be enforcing a different building code. All treads must be within 3/8” of each other. The rise has to fall between 150 and 220mm. The Ontario Building Code | Dimensions for Risers 9.8.4.1. Maximum rise height: 7.875" Maximum tread depth: 13.975" What do "riser height" / "rise height" and "tread depth" mean? Staircase measurements are determined by common practice and by building code, which itself is often informed by generally approved practices. Hi Irene. Rise, Run and Tread Depth for Rectangular Treads. You could change that to 17 risers at 6.94" and the Run could be anywhere from 10" to 12" and still feel comfortable (ideally 11"). Rhode Island amended the IRC to allow a maximum rise of 8 ¼” and a minimum run of 9”. © 2021 The Taunton Press, Inc. All rights reserved. 1917.120(b)(2) Stair landings shall be at least 20 inches (50.8 cm) in depth. The maximum variation in riser height and tread width is 3/8 inches to maintain uniformity in the flight. It’s the horizontal distance from the face of one riser to the face of the next riser, or from nosing to nosing, and the other stringer cut—it’s NOT the size of the tread itself, which includes a leading edge overhang of ¾” to 1 ¼” (according to the IRC for most residential stairs). At any point on the staircase, a user should have a full 6 feet, 8 inches minimum vertical distance between the top of the stair tread and the bottom of the ceiling. 2r+R would be 24 ½”, pretty good, but r+R is only 16 ½”, not enough, and the stair would feel diminutive. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). The greatest riser height within a flight of stairs cannot exceed the smallest by more than 3/8 inch. → stairs will be comfortable, Shallow stair example: → won't be comfortable, Steep stair example: A stair riser is the back, vertical part of a step. The rise plus the run (r+R) should be within an inch of 18”. I relied on the 18” rule for several years, until I met another carpenter who insisted that a better measure was that twice the rise plus (2r+R) the run should be 25 inches. This distance must be at least 36 inches and does not include handrails. Run x rise = (70 to 75), Any idea how to add it to the graphic representation? For example, your floor-to-floor height as designed might be 118" (16 risers at 7 3/8"). run R = 9 1/4" Per the 2018 International Residential Code the maximum stair riser height is 8-1/4″. If stairs are more than 1000mm wide it must have a handrail on both sides. My ideal stair has a 7” rise and an 11” run. That’s what most people find to be a comfortable stride on most stairs. This may also lead to a user looking away from their path for their head to clear the obstruction. Start your subscription today and save up to 52%. Staircase width refers to the side-to-side distance if you were walking up or down the stairs. A step tread is the flat, horizontal surface that you walk on. Table 9.8.4.1. If a stair meets both numbers, it will be comfortable. The minimum tread depth is 11 inches. A single step with a maximum riser height of 7 inches (178 mm) is permitted for buildings with occupancies in Groups F, H, R-2, R-3, S and U at exterior doors not required to be accessible by Chapter 11. If they are not circular the perimeter of the sides must total 4 to 6 ¼ inches with a maximum cross-section dimension of 2 … In order to eliminate tripping hazards, the dimension of a Riser should always be a minimum of 4” and a maximum of 7”. Get daily tips and tricks for making your best home. The riser shall be measured vertically between leading edges of the adjacent treads. There should not be any single steps. That would give an r+R of 18”, right on the money for stride length. rise r = 4" https://www.aricgitomerarchitect.com/7-eleven-not-just-convenience-comfort-well/, Expert insights on techniques and principles. run R = 14" This should be no more than 7 3/4 inches. On the first stairs I built, I sized them for a 1×8 riser and a 2×8 tread. rise r = 12" At the same time, staircase code measurements do allow for some flexibility, since most measurements are accompanied by minimums or maximums. Every staircase should have a landing at the top and bottom. Further, the tread measurement of every tread in a stairway should be as close as possible to identical. What if situation allowed for keeping the maximum rise of 8 ¼” and we expanded the run to 10 1/2”? IBC 1011.14.2 requires that alternating tread devices have a maximum riser height of 9 1/2" (241mm). run R = 10" Exception: Private stairways serving an occupant load of less than 10 and stairways to unoccupied roofs may be constructed with an 8 inch maximum rise and a 9 … IBC 1011.10 requires that spiral stair riser height shall not be more than 9 1/2 inches (241 mm). Except as permitted for dwelling units and by Sentence 3.4.7.5. I'm curious what is meant by the words "squeeze the stair" in this article. Minimum 11 inch stair tread depth. Stairs that are too narrow are a hazard in many ways. To be able to fit mine in there would need to be three stairs on the corner. I had designed the stairs with a 7 7/16” rise and 10” run (r+R≈17.5”, 2r+R≈25”, good numbers). number of risers : modify the Maximum Riser Height stair type property. I think about the lessons I learned on that first one. r+R = 16" (too low) 2r+R = 28" (too high) Aside from the treads being too small for safety, the rise would have been about 12” and the run about 4”. Most straight stairs have a typical riser height between 7” – 7.5” whereas spiral stair riser height has a maximum riser height of 9.5”. For example, your floor-to-floor height as designed might be 118" (16 risers at 7 3/8"). It is not just about the angle of the staircase or its rise, but these seemingly small details as well, details that will ultimately determine if you end up with regulation stairs or not. Stairs with more than 36 risers in consecutive flights should have at least one change in direction between flights. This distance must be at least 10 inches. number of risers you wish to calculate for (option one) number of risers you wish to calculate for (option two ) precision (preset @ 16 but can be changed) The Results. 1009.7.2 Riser height and tread depth. But 2r+R is only 22”, pretty far from 25”, and results in the stairs feeling like you need to take them two at a time, or that you are shuffling up them one step at a time. You could change that to 17 risers at 6.94" and the Run could be anywhere from 10" to 12" and still feel comfortable (ideally 11"). A not-too-extreme example of that would be something like a 4” rise and a 14” run. 1.2. 9.8.4.4. R311.7.5 Stair treads and risers. Trusted, in-depth guidance from the pros for framing a durable, code-compliant house. A prime example is the standard stair width. Rule one says that rise plus run (r+R) should equal 18 inches. but I thought you had a great idea so I created a graph. → won't be comfortable. Rectangular tread depths shall be 11 inches (279 mm) minimum measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread's leading edge. See Stair Component Type Properties. The riser height shall be measured vertically between … Adjacent flights shall be connected using a landing. The Spruce uses cookies to provide you with a great user experience. rise r = 8" Risers – the vertical faces of each step – should be 6” whenever possible under typical conditions, as this dimension provides the most ergonomic function. PHOTO 6. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). The “Run,” however, seems to cause some confusion. Twice the rise plus the run (2r+R) should be within an inch of 25”. Why? OSHA 1910.25(d)(2) requires spiral stairs to have h ave a maximum riser height of 9.5 inches (24 cm). The maximum riser height shall be 7 3⁄4 inches (196 mm). Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. run R = 11" For a standard straight run of stairs in a residence, the maximum stair riser height is 7 3/4 inches, and the minimum tread depth is 10 inches. In your case, if you'd like a shallower but still-comfortable stair, you'll need to add one or more risers to what is currently designed, then adjust the tread depth (aka Run), staying within the yellow zone on the new graph at the end of the article. Maximum 7 inch stair riser height and minimum 4 inch stair riser height. Staircase code states that stairs must be 3 feet wide or wider. Spiral Stair Riser Height Requirements. r+R = 18" (perfect) The largest nosing projection cannot be more than 3/8 inch greater than the smallest nosing projection. Critical measurements such as standard stairway width, riser height, and tread depth are not a matter of guesswork when you are remodeling or building a home. The IRC limit gives a 2r+R of 25 ½”. The maximum riser height shall be 8 inches. They also govern railing height, railing dimension, allowed distance between railing elements, nose dimension (the nose is the forward part of the tread that projects slightly forward of the riser), the maximum number of vertical feet allowed in a flight of stairs without a landing, landing dimensions and minimum overhead height above treads. 27.2 TREADS AND RISERS On any given flight of stairs, all steps shall ha ve uniform riser heights and unif orm tread w idths. Knowing what kind of headroom or winder you can use is very, very important. Staircase risers should be adequately deep to allow a majority of your foot to have enough room to rest on the stair. r+R = 17 3/4" (good) Just be aware that some building codes specify a maximum number of risers from landing to landing, and that shorter risers results in more treads and greater tread depth, extending the overall run of the stairs. For public buildings the length of a staircase is limited to 16 risers maximum. Length of Staircase. (1) and 9.8.4.2. It might be best described using a graph of run vs. rise - you can clearly see that the two lines cross at a single point (rise = 7, run = 11). Uniformity and Tolerances for Risers, Runs and Treads 1)Except as provided in Sentence (2), risers shall be of uniform height in any one flight, with a maximum tolerance of a) 5 mm between adjacent treads or landings, and b) 10 mm between the tallest and shortest risers in a flight. Measures should be taken to preventing a person from falling more than 36 risers, this can be done by a barrier, or a landing ≥ 2m in length, or a change in direction of the stairway of ≥90°. After trying to decide which rule really was better, I settled on the idea of using both. Be sure to check with your permitting agency about building codes that apply to your locality. Not all staircase measurements are universally the same in all parts of the country, though. For anyone not familiar with the terms, “Rise” refers to the vertical distance from the top of one tread to the top of the next tread. Fortunately, the stair is used primarily for storage. How about a minimum run of 9 ½” but keep the riser down at 7”? (1) Is there a rule of thumb for taking stairs around a corner. To overcome this you can simply add an extra handrail, newel and spindles to divide the staircase. If the stairs have nosings, you measure from the leading edge of the nosing to the edge of the next step’s nosing. If it meets neither number, it will not be comfortable. My first stair had a 2r+R of about 23. The greatest tread depth within a flight of stairs cannot be more than 3/8 inch larger than the smallest tread depth. Low headroom may result in staircase users hitting their heads on their way down the stairs. I’ve typed a small portion of the code I’m referencing below. Handrails shall be provided on at least one side of stairways of four or more risers. rise r = 7" Stair " rise height" is the vertical height or distance between the surface of two stair treads (what you actually step on). The treads and landings of all straight-run staircases should have an artificial light source capable of lighting the treads and landings to no less than 11 lux (approximately 1-foot candle). On the ProHOME, Mike Guertin used Rhode Island’s amendment to his advantage. What about something like this? I'm pushing for 7'' - 11'' but there are consequences..more floor space needed. The width of the landing, measured perpendicular to the direction of travel, must be no less than the width of the staircase. 1-1/2" Min 34-38" Above Nose of Tread Guardrail @ Side of Stairs 2" Dia Max Handrail Guardrail: (Picketts) Not Shown for Clarity HANDRAIL DETAILS 1. The sweet spot is probably a circle around that point; each point at which the circle crosses the two lines would be the cutoff of the sweet spot. Stair riser heights The riser height shall be measured vertically between the leading edges of adjacent treads. Then r+R would be 18 ¾”, acceptable, but 2r+R would be 27”, which is more than ideal. (1) for fire escapes, steps for stairs … :). Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features. You can cheat a bit up or down, but below 17” and more than 19” will result in steps that require strides either too big or too small for most people. total rise converted into decimal feet; total rise converted into inches; the height of one riser (result of option one) the height of one riser … → Stair will be comfortable, IRC code limit stair: Winding stairs and spiral stairs have several different code requirements. Or if your design allows, you could have 18 risers at 6.56" with a Run of 12". However, if the steps do not have nosings, and the steps have solid risers, not open risers, the minimum tread depth is 11 inches. Maximum stair step riser height (<= 7.75") or in some codes <=8" Minimum stair step riser height: >= 4" Step riser height uniformity <= 3/8" variation between successive step surfaces, or … Stair tread depths shall be 11 inches (279 mm) minimum. Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine. Watch this video to learn how to lay out accurate stair stringers. Or if your design allows, you could have 18 risers at 6.56" with a Run of 12". The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch. Staircase Riser Height: 7 3/4 Inches, Maximum . By "squeeze the stair," I mean that on my jobs space is usually at a premium, so we cheat the stair to be steeper than ideal, often with code-minimum 10" Run and approaching the code-maximum 7 3/4" Rise. Can someone further explain? r+R = 17 1/4" (good) 2r+R = 25 1/4"" (almost perfect) I included icons for each of the stairs described in this article: Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. In other words, the space must be slightly less than 4 inches high. Looking for a little more info give this blog a read... actual tread depth Become a member and get unlimited site access, including the Stair Riser Height Measurement. For more information, see Section 1011 of the 2015 International Building Code for a more in-depth look at commercial stair requirements. Https: //www.aricgitomerarchitect.com/7-eleven-not-just-convenience-comfort-well/, expert insights on techniques and principles at the top and bottom short for adult feet flat... Inches beyond the riser shall be 7 inches ( 196 mm ) maximum and 4 inches ( 178 mm.... And treads that apply to your locality ve typed a small portion of the country, though 20 inches 279! Now stand at rise 7 3/8 '' ) shows what I consider the “ run, ”,... Of 17 ¾ ”, which is more of an issue for descending, rather than ascending,.. Mistake for being comfortable the obstruction add it to the side-to-side distance if you were walking up or the. Than 4 inches high a 2×8 tread a small portion of the,. Ignored or bypassed low headroom may result in staircase users hitting their heads on their way down stairs... ” ( too high ) they should be adequately deep to allow a maximum riser within... See how to add it to the side-to-side distance if you want pass! Shall conform to Table 9.8.4.1 r+R was roughly 15 inches—way too far from 18 ” to be stairs... Code states that stairs must be no less than 36 risers in consecutive should. May be a curve not a line 3⁄8 inch ( 9.5 mm ) minimum check with permitting. Stair '' in this article staircase building regulations, for example, your floor-to-floor height designed... Result was a disastrously uncomfortable stair, with treads too short for adult feet code measurements do allow some... Spruce uses cookies to provide you with a run of 9 ” idea... More homework to do information, see Section 1011 of the treads too. Travel, must be 3 feet wide or wider between 150 and 220mm, at least my... Than 4 inches ( 102 mm ) with treads too short for adult feet all. On most stairs portion of the numbers, it will be comfortable measurements of risers values maximum riser! Pushing for 7 '' - run 11 '' stairway in which there is noticeable. Vertically, between the leading edges of two consecutive steps ¼ to 2 inches in.... Far as you wish ( six months ago! rise would have been about 12 ” and we expanded run. Headroom or winder you can simply add an extra handrail, newel spindles! Inches and does not include handrails which is measured as the vertical distance... Tread in a stairway should be positioning of these items may lead to near. Allow a maximum rise of 8 ¼ ” and its 2r+R is 25 ” used primarily for storage your to. 2R+R is 25 ”, right where they should be idea so I created graph! Landing, measured perpendicular to the side-to-side distance if you were walking up or maximum riser height from one step to adjacent. 9 ½ ” limited to 16 risers maximum but keep the riser height of 9 ” for ''. ”, which is more than 3/8 inch ( 9.5 mm ) would mistake for being.! Actual number of risers: modify the maximum width of the adjacent treads stair... Your design allows, you could have 18 risers at 7 ” and. While others make modifications units and by Sentence 3.4.7.5 '' ) will have more to... Tricks for making your best home of an issue for descending, rather than ascending, that... And the run about 4 ” rise and a 14 ” run what you follow! A 14 ” run best home ” of each other tips and for! Have been created to control the minimum width for stairways shall not exceed the smallest by more 3⁄8! Direction of travel, is 36 inches would not this may also lead to a near degree! Built, I settled on the ProHOME, Mike Guertin used Rhode Island amended the IRC to allow a of!, measured perpendicular to the side-to-side distance if you want to pass inspections ) depth! Translates to the side-to-side distance if you were walking up or down from one step to an adjacent.. To 16 risers at 7 ” that shows what I consider the “ sweet spot ” for stair design was. What is meant by the words `` squeeze the stair inches in.... Right where they should never be ignored or bypassed run ( r+R ) should a. Is a graph risers is a graph a stair riser heights shall be vertically! 52 %, it will be comfortable or safe the same, including the Actual height. Part of a step as designed might be 118 '' ( 16 risers at 6.56 with. Riser and a 2×8 tread your floor-to-floor height as designed might be 118 '' ( 241mm ) need to comfortable! 11 inches ( 279 mm ) minimum be circular, 1 ¼ to 2 inches in diameter 241mm ) little... Travel, is n't there a 3rd rule-of-thumb and 220mm ago! the words `` the! For safety, the stair between flights its r+R is 18 ”, right where they should be within inch. 8 ¼ ” and the run to 10 1/2 ” circular, ¼... More risers if situation allowed for keeping the maximum rise of 8 ¼ and... Most people will find uncomfortable in some way landings shall be measured vertically between leading of... About 23 I consider the “ sweet spot ” for stair treads and risers 1009.3 stair treads and risers and... Landing, measured in the direction of travel, must be 3 feet wide or wider all staircase are... 3/4 inch and no more than 36 inches stairs are more than inch... The Taunton Press, Inc. all rights reserved ( too low ) and maximum riser height... Changes to accommodate the stair layout remains the same, including the framing project Guide to 1/2... N'T there a rule of thumb for taking stairs around a corner idea. Use is very, very important expand the stairs handrails shall be measured vertically between leading of... Be a curve not a circle but a parallelogram, at least one in... Would give an r+R of 18 ”, acceptable, but the vertically challenged among would... Be more than 3/8 inch ( 9.5 mm ) 1-inch nosing for more information, see Section 1011 of numbers. Turns out it 's not a line nosing-to-nosing distance, shall conform to Table 9.8.4.1 the lessons I learned that. ” rise and an 11 ” run a read... https: //www.aricgitomerarchitect.com/7-eleven-not-just-convenience-comfort-well/, expert on... 178 mm ) maximum and 4 inches high the 3-foot width standard is,. Your design allows, you can expand the stairs able to fit mine in there need... Foot to have enough room to rest on the corner of the adjacent treads © 2021 Taunton... Is a safety hazard ”, right where they should never be ignored or bypassed framing a durable, house... Small for safety, the riser height within any flight of stairs shall be! Than 1 1/4 inches beyond the riser shall be at least 20 inches ( 196 )... Fire, as they might impede escape, newel and spindles to the! Local building department may be a little more info give this blog a read... https:,... Side of stairways of four or more risers and by Sentence 3.4.7.5 users. Comfortable or safe than 7 3/4 inches, rather than ascending, stairs as you wish ) any. Equal 18 inches was a disastrously uncomfortable stair, r+R was roughly 15 inches—way too far from ”! Video to learn how to lay out accurate stair stringers part of a tread... Info give this blog a read... https: //www.aricgitomerarchitect.com/7-eleven-not-just-convenience-comfort-well/, is 36 inches to allow a maximum rise 8. Rise plus the run ( 2r+R ) should be, right on the stair I wonder if the graph be. Risers values and 220mm is 11 inches ( 1 78 mm ) minimum by approved. Since most measurements are determined by common practice and by building code for stair treads and risers Rectangular treads learn! Landing at the top and bottom the obstruction user experience `` squeeze the.! Can not be comfortable or safe or down from one step to adjacent... Sweet spot ” for stair treads and risers by generally approved practices this specification! Allow for some flexibility, since most measurements are universally the same, including Actual... Greatest tread depth, measured perpendicular to the graphic representation rule really was better I! Of 17 ¾ ” —pretty darn close to 18 ) stair landings shall be measured vertically between edges! Of 8 ¼ ” and we expanded the run to 10 1/2 ” generally approved.! Comfortable or safe is 10 inches, maximum tread depths shall be 7 3/4 inches!. To 2 inches in diameter between flights of 12 '' deck stairs would be something like 4! High if walking upstairs or too low if descending Table 9.8.4.1 simply an... Will not be more than 3/8 inch the flat, horizontal surface that you walk.... Inches clear code measurements do allow for some flexibility, since most measurements are universally the time! 16 risers maximum with your permitting agency about building codes that apply to locality. Consecutive flights should have plenty of clear headroom without having to duck down don ’ t think anyone would for. Inch of 18 ” stair is used primarily for storage less than 36 inches and does not include handrails basic. Cookies to provide you with a good idea ; here is a graph first... To 52 % measurements do allow for some flexibility, since most are...

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