# what is the maximum height of a stair riser

It is not likely that stairs would even be recognizable without the addition of the riser, because this key element is what gives stairs their gradual increase in height. It's used in calculations to determine a safe and comfortable design. Watch out: at STAIR RISER SPECIFICATIONS and at STAIR DIMENSIONS, WIDTH, HEIGHT you'll read that stair risers should be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. More importantly, they show that compliance with OSHA's requirements for the safe use of ladders and stairways could have prevented many of these injuries. 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”. Approved Document K requires that dwellings with more than 36 risers in consecutive flights of stairs, have at least one change of direction, with a landing that has a minimum length equal to the width of the stairs. The number of risers, not the number of treads, is used to determine the number of steps that comprise a staircase. Take the minimum riser height of 150mm. Nosing Protrusion: 1.5" | 38 mm max. Apologies for the delay. c. General access stairs (all other buildings): max Rise = 170 mm; min going = 250 mm. A stair riser is located at the front edge of each step. This is a somewhat cramped building and the stairs were put in as small a space as possible to maximize the usable square footage. The rise has to fall between 150 and 220mm. For utility stairs, the max rise is 190 mm and the min going is 280 mm. Divide the overall change in level (overall rise) by 150mm. What are the Best Tips for Building Basement Stairs. b. Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly. 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. John Wiley & Sons, 2006. Maximum pitch: 38°. Keep in mind the straight stair riser height and spiral stair risers height is different. The stair part marked D is the. The riser element of a set of stairs is generally a plank or board installed vertically at an angle of approximately 90 degrees to the stair risers above and below it. If the total height from where the stairs will begin to where they will end is 56 inches (142 cm), then the contractor can divide 56 inches (142 cm) by 7 inches (17.78 cm) to determine that he or she will require eight stairs in total. Maximum riser height, typically 8.25 inches (210 mm). On the other hand, a stair that is 5 inches high and 13 inches long might be acceptable, according to building safety suggestions. For stairs on a 40-degree angle, the rise must be 8 inches. Maximum pitch: 42°. Residential building codes will typically allow for steeper stairs than public building codes. What are the Different Types of Stair Gates? Stair risers that are too short result in very flat flights of stairs that … baluster. Note: a tangent is a ratio of two sides of a triangle - in our case the stair triangle shown above. The minimum tread depth is 10" and the maximum riser height is 7-3/4". The vertical difference between a stair tread nosing and any structure or ceiling above the stairway is known as the . These notes describe an ideal stairway slope or angle and in a table we give the stairway as well as access ramp "steepness" expressed as stair or ramp angle, slope, and as typical step riser height and tread depth dimensions. 7" Riser Height / Tread-Depth-Y = 0.7535 = 37° slope 37° slope converts to 75.3 % or in decimal form a slope of 0.7535. Note: that divisor of 360 is the number of degrees in a full circle. A stair riser accounts for the vertical distance between one step and the next. The reason for this is that as all the treads are set to a near 30 degree angle. Nosing Radius: .5" | 13 mm max. These data demonstrate that work on and around ladders and stairways is hazardous. We have no relationship with advertisers, products, or services discussed at this website. So, while there may be no code stipulating the size of the lumber you can use, the load and riser height and tread depth requirements do limit the dimensional lumber that will work as a stringer. Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. (3) Except in fire escape stairs and where an exterior stair adjoins a walkway as permitted by Sentence 3.4.6.3. What Are the Different Options for Stair Edging? But it would be slightly uncomfortable based on the second rule, given that double the rise plus the run equals 23. Maximum length of a flight of stairs - Designing Buildings Wiki - Share your construction industry knowledge. @Soulfox -- I hope your office doesn't own that building. ; 7" | 180 mm max. InspectAPedia tolerates no conflicts of interest. Continue reading at STAIR ANGLE & SLOPE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX. And making such modifications is rarely cheap. For risers, the minimum dimensions are 130 mm, and the maximum is at 225 mm. Standard Stair Riser Height Requirements. Some codes specify slightly taller stair risers, from 8" to 8 1/4" (Canada, for example). skirtboard. The total of the rise plus the run is 18, which meets the ideal, according to the first rule. That means a shorter staircase so the stairs had to be taller. Using the numbers I suggested above, and looking at the slope or angle of a stairway represented by a single step (rise & run) we have the following: To convert a % grade to slope we convert the percent slope to a decimal by dividing by 100, then find the inverse tangent of that value to convert to degrees. 178.6 mm (riser) Calculating tread and riser sizes The proposed stair is 2.5 m high (see Figure 3). Stair tread depths shall be 11 inches (279 mm) minimum. Tangent or "Tan" is the reverse of Arctan. 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. I believe in-house stairs are generally on the order of 7-1/2" or so, but, if I'm not mistaken, pool steps typically have a greater drop to them. The size of stair risers can vary depending on the total amount of space available, design aesthetic, or personal preference. nosing return. This means your stair risers should be less than or equal to 7 3/4 inches. On the other hand, tall people may find it uncomfortable to climb stairs with short risers. nosing. Best practices for stair layout & design: Here we describe the measurements for stair building that give a good starting point from which you can adapt the stairs to your specific need in total stair rise or height and run or length. 7" Riser Height / Tread-Depth-Y = 0.7535 = 37° slope, Again using Mrs. Revere's elementary school algebra instructions, we can re-write the formula as. 1.2. Riser Height: 4" | 100 mm min. 7" The stair part marked A is the. Riser height and tread depth should be of a uniform height within a tolerance of ±5mm, in one flight. By "ideal stairway" we mean a stair that complies with building codes and recommended stair construction standards and that produce a stair that is comfortable to climb or descend. If you want to pass spiral staircase building regulations, for example, you will have more homework to do. Note that dimensions here should be taken excluding carpets, rugs, or runners. Building codes generally suggest that the maximum height of a riser be 7.75 inches (19.7 cm) Nosing: The nosing is the protrusion at the edge of a tread that hangs over the riser below. When combining the Riser + Going to get the slope relationship, the minimum length is 540 mm, with the maximum at 700 mm. Minimum rise height . Maximum rise height: 7.875" Maximum tread depth: 13.975" This tells us that with a riser of 150mm we will need 3 risers/steps. For those with shorter legs, it may be difficult to climb stairs if there are tall risers. 1.1. Stair risers that are too short result in very flat flights of stairs that ascend very slowly and require frequent, short steps. Using simple algebra we re-arrange the formula above to read. We would need change the stair tread depth to make a 37° slope stair that has an acceptable 7-inch riser height. A stair riser is the back, vertical part of a step. NCC Part 3.9.1.4 – Stair Construction With Slip Resistance ::: As a general rule, stair risers should not be less than 4 inches (10 cm) tall, but their height should not exceed 7.5 inches (19 cm). The height of each step is called the rise. -osha.gov/doc/outreachtraining/htmlfiles/stairlad.html, 7" / 11" = 0.64 or about a 64% grade or slope. SeeBUILD a STAIR to a SPECIFIC ANGLE or SLOPE, CALCULATE stair tread depth or riser height from stairway slope in degrees, ROOF SLOPE CALCULATIONS for a complete explanation of the mathematics of calculating stair or roof slope, angle, pitch, rise, run, etc. Step riser specifications riser height (<= 7.75" or in some codes <= 7.0" or in Canada <=8.25") maximum and 4 inches (102 mm) minimum. [26] >Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989. How about 10"? 7, Â§3231. Staircase riser height translates to the distance you move your foot either up or down from one step to an adjacent step. "Riser height" is the vertical distance from one step to the next. Is 12" too much? My office has a staircase where the risers are too tall and the resulting stairs are hated by just about everyone who comes in here. If so, your company might be on the hook if anyone who has a disability can't get up those stairs. 450mm / 150mm = 3. 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. Stairways [PDF] Fig. The height of stair risers depends on the incline of the staircase and the personal needs of the user. Online, Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the, Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com. Watch out: at STAIR RISER SPECIFICATIONS and at STAIR DIMENSIONS, WIDTH, HEIGHT you'll read that stair risers should be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. The riser height shall be measured vertically between the leading edges of adjacent treads. 101-A& 101-B (may appear as ANSI B101.0) sets rules for measuring walkway slip resist, OSHA - (Dept of Labor CFR 1910.22 does not specify COF and pertains to workplaces) but recognizes the need for a "qualified person" to evaluate walkway slipperiness, ADA (relies on the ANSI and ASTM standards)Â, [43] International Building Code, Stairway Provisions, Section 1009: Stairways and Handrails, retrieved 8/29/12, original source: http://www.amezz.com/ibc-stairs-code.htm [copy on file as IBC Stairs Code.pdf], [44] Model Building Code, Chapter 10, Means of Egress, retrieved 8/29/12, original source: http://www2.iccsafe.org/states/newjersey/NJ_Building/PDFs/NJ_Bldg_Chapter10.pdf, [copy on file as NJ_Bldg_Chapter10.pdf] adopted, for example by New Jersey. Illustration: adapted from California Title 8, Ch. Maximum Stair Riser Height. No taller. You also will need to establish the tread depth and riser height for each step using our Decks.com Stairs Calculator. Tread Depth: 11" | 280 mm min. Another key element of a stair riser is its width. Eg: 7" rise / 11" run = 0.636 decimal slope, Degrees of Slope = [ArcTan (% Slope / 100)], Eg: [ArcTan (64% slope / 100)] = [ArcTan .64] = 32.6° slope, Percentage Slope = [ Tan ( Degrees of Slope ) ] x 100, Eg: [Tan 32.6° Slope] x 100 = 63.9 or about 64% slope. Divide the height of the flight by the maximum riser height to calculate how many risers are required: 2500 / 190 = 13.16 The maximum allowed riser height is 190 mm, so 14 risers are needed. The height of stair risers is essential to consider when constructing a flight of stairs, because that measurement is crucial to figuring out how many stairs are needed. Stair risers are usually not more than 1 inch (2.54 cm) thick. If stairs are built with a 37° stairway slope, what would be the step rise (Rise-X) if we use an 11-inch deep stair tread? For example, if a contractor decides he or she wants stair risers no taller than 7 inches (17.78 cm), the contractor can use this figure to determine how many stairs need to be built. Rises that are not exactly the same height are a serious fall risk. The going must be betwee… However the IRC does reference and use the following ANSI standard for minimum riser height. Using any online or textbook trigonometry tables we look up the arctan value of 0.64 (as that's easier than re-learning the trigonometry to calculate it). Stair riser heights shall be 7 inches (1 78 mm) maximum and 4 inches (102 mm) minimum. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code. We describe how to translate the stair rise and run into a specific number of stair treads and risers that will be uniform and of proper (safe) dimension. (3), risers, measured as the vertical nosing-to-nosing distance, shall be of uniform height in any one flight, with a maximum tolerance of, (a) 5 mm between adjacent treads or landings, and The stair part marked C is the. This should be no more than 7 3/4 inches. Utility (Public) Max Rise = 190mm, min going 250mm. Stair Riser Height. Any heights in between these two guidelines are typically considered acceptable for stair risers because they allow people walking up the stairs to assume a comfortable stride and pace. Risers (the vertical element connecting treads) that are no less than 6 inches in height and no more than 7.5 inches. This article series describes proper stair construction specifications, dimensions, measurements & codes. We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. [27] "The Dimensions of Stairs", J. M. Fitch et al., [28] Stair & Walkway Standards for Slipperiness or Coefficient of Friction (COF) or Static Coefficient of Friction (SCOF), NSFI 101-BÂ (National Floor Safety Institute), NSFI Walkway Auditing Guideline (WAG) Ref. For private stairs (domestic houses), the max rise is 220 mm, and the min going is 220 mm. STAIRWAY SLOPE or ANGLE & STAIR TREAD SLOPE, California Title 8, Ch. LAPro: 4.921" LA1: 5.125" Minimum tread depth: 8.268" Maximum step dimensions. 1. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also, [7] The Circular Staircase, Mary Roberts Rinehart, [8] Construction Drawings and Details, Rosemary Kilmer, [9] Falls and Related Injuries: Slips, Trips, Missteps, and Their Consequences, Lawyers & Judges Publishing, (June 2002), ISBN-10: 0913875430 ISBN-13: 978-0913875438, [19] Common Sense Stairbuilding and Handrailing, Fred T. Hodgson, [21] Building Stairs, by pros for pro, Andy Engel, [22] A Simplified Guide to Custom Stairbuilding, George R. Christina, [23] Basic Stairbuilding, Scott Schuttner, [24] The Staircase (two volumes), John Templar, Cambridge: the MIT Press, 1992, [25] The Staircase: History and Theories, John Templar, MIT Press 1995. The code specifies that risers should not be more than 7 ¾ inches in height and that any variation of risers within a flight of stairs should not be more than ⅜ inch. Each individual stair riser is usually no taller than 7.5 inches (19 cm), but as many as needed can be used to span the distance between the bottom of the flight and the top. Or see STAIR CONSTRUCTION, SPECIFIC ANGLE or SLOPE. OSHA and IBC also have different maximum stair riser height requirements depending on the type of stairway. Those with shorter legs, it may be difficult to climb stairs if there are tall.! 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By the amount of steps we want: 450mm / 2 = 225mm longer, which meets ideal... – stair construction specifications, dimensions, the rise & tread of stairs ascend... Legs, it may be difficult to climb stairs with short risers can depending! A 40-degree angle, the max rise is 220 mm, and the maximum is at 215 while! ±5Mm, in one flight: a Free Tool that Saves you Time and Money, 15 Ways. Backs instead of three the back, vertical part of a uniform height within any flight of stairs Designing! Also provide Conversion Formulas for stair Rise/Run, Percent slope & angle degrees calculations from California Title,! Tread-Depth-Y = 0.7535 = 37° slope converts to 75.3 % or in decimal form a slope of 0.7535 are to... Inch ( 2.54 cm ) thick either up or down from one step and the min going is mm. You will have more homework to do example, outdoor deck steps often open!: 8.268 '' maximum step dimensions to be taller = 250 mm stair a. One flight maximum length of a pool step that you would suggest, measurements &.! Less than 6 inches in height and no more than 7.5 inches Rizzoli 1989. Proposed stair is 2.5 m high ( see Figure 3 ) Except in fire escape stairs and where an stair... The nosings of adjacent treads if you want to pass spiral staircase what is the maximum height of a stair riser regulations, for example, outdoor steps... The usable square footage within any flight of stairs that … riser height translates to the you... Stairways is hazardous or Arc Tan no good solution to that design building and the maximum stair riser /... 0.7535 = 37° slope converts to 75.3 % or in decimal form a slope of.. Lapro: 4.921 '' LA1: 5.125 '' minimum tread depth to make 37°. The maximum riser height is no good solution to that design ) max rise is 220 mm and! Get up those stairs nosing Radius:.5 '' | 13 mm max stairs that … riser height 100! Winder you can use is very, very important stairs with short risers above the stairway known... Title 8, Ch stair risers, the max rise =170mm, min going 250mm,! Height requirements depending on the second rule, given that double the rise & of... Hope your office does n't own that building a riser of 150mm we will 3... Flights of stairs the change in level ( overall rise ) by.. Are not exactly the same height are a serious fall risk ( c ), the tread. The amount of space available, design aesthetic, or services discussed at this website going = 250 mm and... 450Mm / 2 = 225mm to climb stairs if there are tall risers an exterior stair adjoins a as! Total amount of steps we want: 450mm / 2 = 225mm mobility or seniors seniors! Depths shall be 11 inches ( 210 mm ) '' / 11 '' = 0.64 or about a 64 grade. Be 11 inches ( 279 mm ) minimum the maximum riser height shall be inches... Will typically allow for steeper stairs than Public building codes stairway is known as the knowing what of... Vertical element connecting treads ) that are too short result in very flat flights of,! ( riser ) Calculating tread and riser sizes the proposed stair is 2.5 m (. About a 64 % grade or slope on and around ladders and stairways is hazardous looking at a of! From the closely-related articles below, or services discussed at this website ( overall rise ) 150mm! The stairs were put in as small a space as possible to the... 355 mm Title 8, Ch example, outdoor deck steps often have open backs instead having! % or in decimal form a slope of 0.7535 vertically between the leading of! Means a shorter staircase so the stairs piece that appears to connect the horizontal treads of each step,. You will have more homework to do readers to a companion article on Designing comfortable stairways for people limited. 3/8 inch maximum and 4 inches ( 102 mm ) 170 mm ; min going 250mm small space! A is the maximum riser height of each step of 7-3/4 ” no. And riser height is different: //www.dir.ca.gov/title8/3231.html be less than 6 inches in height and stair. Slope = angle in degrees / 360 x 100 this means your stair risers are usually more.

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