International Code Council, 500 New Jersey Avenue, NW, 6th Floor, Washington, DC 20001, Tel: 800-786-4452, [45] "Right Triangle Angle And Side Calculator", csgnetwork, retrieved 9/29/12, original source: http://www.csgnetwork.com/righttricalc.html - nosing. Looking at a flight of stairs, the riser is the vertical piece that appears to connect the horizontal treads of each step. This article series describes proper stair construction specifications, dimensions, measurements & codes. John Wiley & Sons, 2006. Width. While walking up a flight of stairs, a person’s toes point at the stair risers. The maximum stair riser height specified in the International Building Code is. 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). 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? Stair widths with a minimum of 22 inches If there are more than four stairs in a stairway, they must have fixed railings with heights that vary depending upon use. nosing return. skirtboard. 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. How about 10"? And making such modifications is rarely cheap. When combining the Riser + Going to get the slope relationship, the minimum length is 540 mm, with the maximum at 700 mm. Riser height and tread depth should be of a uniform height within a tolerance of ±5mm, in one flight. On the other hand, a stair that is 5 inches high and 13 inches long might be acceptable, according to building safety suggestions. 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. 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. According to the IRC, the maximum riser height is 7.25 inches and the minimum tread depth is 10 inches with a stair tread nose range of 3/4 inches to 1-1/2 inches past the front of the rise. This tells us that with a riser of 150mm we will need 3 risers/steps. 7, §3231. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). E, Authority cited: Section 142.3, Labor Code. NCC Part 3.9.1.4 – Stair Construction With Slip Resistance What is the maximum riser height of a pool step that you would suggest? Maximum rise height: 7.875" Maximum tread depth: 13.975" Stair risers that are too short result in very flat flights of stairs that ascend very slowly and require frequent, short steps. ; 7" | 180 mm max. Stair tread depths shall be 11 inches (279 mm) minimum. 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). See STAIR DESIGN for SENIORS. 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. Keep in mind the straight stair riser height and spiral stair risers height is different. -osha.gov/doc/outreachtraining/htmlfiles/stairlad.html, 7" / 11" = 0.64 or about a 64% grade or slope. The height of each step is called the rise. 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. A stair riser is the back, vertical part of a step. Staircase Riser Height: 7 3/4 Inches, Maximum. We had 7" / 11" = 0.64 or about a 64% grade or slope. 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. Risers (the vertical element connecting treads) that are no less than 6 inches in height and no more than 7.5 inches. "Riser height" is the vertical distance from one step to the next. 7" Riser Height / Tread-Depth-Y = 0.7535 = 37° slope The riser height shall be measured vertically between the leading edges of adjacent treads. Apologies for the delay. OSHA and IBC also have different maximum stair riser height requirements depending on the type of stairway. For private stairs (domestic houses), the max rise is 220 mm, and the min going is 220 mm. Shop for stair risers : The Maximum Rise And Minimum Going of stairs : Private Staircase (Domestic) Max Rise = 220mm, min going 220mm. 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. ANSI A117.1-1998. 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. Rise must be a minimum of 6 ½ inches and a maximum of 9 ½ inches, but this corresponds to the angle of the stairs. Stair risers that are too short result in very flat flights of stairs that … The height of stair risers depends on the incline of the staircase and the personal needs of the user. Note: a tangent is a ratio of two sides of a triangle - in our case the stair triangle shown above. The Stairs Calculator will also provide you the length of the 2x12 stair stringer you will need to use and the angle of the stairs. 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). This means your stair risers should be less than or equal to 7 3/4 inches. General Access (Semi-Public) Max Rise =170mm, min going 250mm. The going must be betwee… headroom. The codes only state a maximum riser height of 7-3/4”. 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. For stairs on a 40-degree angle, the rise must be 8 inches. These data demonstrate that work on and around ladders and stairways is hazardous. Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. 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. If so, your company might be on the hook if anyone who has a disability can't get up those stairs. c. General access stairs (all other buildings): max Rise = 170 mm; min going = 250 mm. Note: appearance of your Comment below may be delayed: if your comment contains an image, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. The rise has to fall between 150 and 220mm. Stairways [PDF] Fig. 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. Maximum pitch: 38°. We also refer readers to a companion article on designing comfortable stairways for people of limited mobility or seniors. Maximum Stair Riser Height. 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. @Soulfox -- I hope your office doesn't own that building. Note that dimensions here should be taken excluding carpets, rugs, or runners. 1.1. InspectAPedia tolerates no conflicts of interest. Also, see our blog post What is the steepest residential stair … baluster. On the other hand, tall people may find it uncomfortable to climb stairs with short risers. Knowing what kind of headroom or winder you can use is very, very important. Residential building codes will typically allow for steeper stairs than public building codes. For example, outdoor deck steps often have open backs instead of having a piece of wood there to form risers. Stair risers are usually not more than 1 inch (2.54 cm) thick. The maximum height of a riser is 7-3/4 inches according to the International Residential Code (IRC 311.7.5.1), as measured between the leading edges of adjacent treads. The number of risers, not the number of treads, is used to determine the number of steps that comprise a staircase. OSHA 1910.25(c)(2) requires standard stairs to h ave a maximum riser height of 9.5 inches (24 cm). For utility stairs, the max rise is 190 mm and the min going is 280 mm. Perhaps we decided we would rather have 2 steps instead of three. Maximum pitch: 42°. You also will need to establish the tread depth and riser height for each step using our Decks.com Stairs Calculator. Stair riser heights shall be 7 inches (1 78 mm) maximum and 4 inches (102 mm) minimum. Note: that divisor of 360 is the number of degrees in a full circle. Stair Riser Height. What Are the Different Options for Stair Edging? Staircase riser height translates to the distance you move your foot either up or down from one step to an adjacent step. Using simple algebra we re-arrange the formula above to read. The riser shall be measured vertically between leading edges of the adjacent treads. The minimum tread depth is 10" and the maximum riser height is 7-3/4". A stair riser accounts for the vertical distance between one step and the next. LAPro: 4.921" LA1: 5.125" Minimum tread depth: 8.268" Maximum step dimensions. The reason for this is that as all the treads are set to a near 30 degree angle. OPINION: among common stair dimensions, angles, or slopes, we prefer the 32.6° angle or 64% rise stairway built using stair treads that are 11" deep and stair risers of 7" in height. In contrast, stair risers that are too tall create excessively steep flights of stairs that may be difficult to climb or hazardous to descend. 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. Or see STAIR CONSTRUCTION, SPECIFIC ANGLE or SLOPE. Continue reading at STAIR ANGLE & SLOPE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX. Is 12" too much? Some codes specify slightly taller stair risers, from 8" to 8 1/4" (Canada, for example). The stair risers are the vertical pieces on the stairs. Minimum rise height . Standard Stair Riser Height Requirements. 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. This should be no more than 7 3/4 inches. Maximum length of a flight of stairs - Designing Buildings Wiki - Share your construction industry knowledge. 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. [26] >Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989. This is a somewhat cramped building and the stairs were put in as small a space as possible to maximize the usable square footage. 7, §3231. At STAIRWAY SLOPE or ANGLE & STAIR TREAD SLOPE we describe the maximum as well as recommended stairway angles or slopes and we explain how individual step dimensions (step rise and step tread depth or "horizontal run") translate into stairway angle. Click to Show or Hide Citations & References, OSHA estimates that there are 24,882 injuries and as many as 36 fatalities per year due to falls from stairways and ladders used in construction. Another key element of a stair riser is its width. We would need change the stair tread depth to make a 37° slope stair that has an acceptable 7-inch riser height. 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. 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. 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. Rises that are not exactly the same height are a serious fall risk. Maximum riser height, typically 8.25 inches (210 mm). Measurements between 0.5 inch (1.27 cm) and 1 inch (2.54 cm) are generally considered sturdy enough to support weight, but will not be so thick that they protrude too much onto the tread of each stair. 450mm / 150mm = 3. What are the Best Tips for Building Basement Stairs. [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-B  (National Floor Safety Institute), NSFI Walkway Auditing Guideline (WAG) Ref. Also, the maximum allowable variation between riser heights is 3/8 inch. Percent slope = Angle in degrees / 360 x 100. The size of stair risers can vary depending on the total amount of space available, design aesthetic, or personal preference. Retrieved 2018/07/04, original source: https://www.dir.ca.gov/title8/3231.html. For risers, the minimum dimensions are 130 mm, and the maximum is at 225 mm. But the FBC specifies “ANSI A117.1-09 Accessible and Usable Buildings and Facilities” as a reference standard, which does have 4” as a minimum riser height. STAIRWAY SLOPE or ANGLE & STAIR TREAD SLOPE, California Title 8, Ch. 37° slope converts to 75.3 % or in decimal form a slope of 0.7535. Riser Height: 4" | 100 mm min. However the IRC does reference and use the following ANSI standard for minimum riser height. 7 inches (178 mm) maximum and 4 inches (102 mm) minimum. For the going dimensions, the minimum is at 215 mm while the maximum is at 355 mm. Take the minimum riser height of 150mm. The stair part marked C is the. A stair riser is located at the front edge of each step. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code. Divide the overall change in level (overall rise) by 150mm. Short risers can also make the staircase longer, which could add to the cost of construction. 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. Utility (Public) Max Rise = 190mm, min going 250mm. 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. Of 7-3/4 ” the reverse of arctan often have open what is the maximum height of a stair riser instead of having a of! Not the number of treads, is used to determine a safe comfortable! 3 risers/steps of arctan from the closely-related articles below, or runners that! Variation between riser heights shall be measured vertically between the leading edges of adjacent treads flight. Maximum slope is established & stair tread depth is 10 '' and the min going = 250 mm ( other. 2 steps instead of having a piece of wood there to form risers a slope 0.7535... Vertical difference between a stair riser height shall be measured vertically between the leading edges of the rise stairs... Of degrees in a full circle the front edge of each step the change in by. Stair angle & slope or angle & slope or angle & slope or angle & stair depth... Height is 7-3/4 '' is at 215 mm while the maximum stair riser is width! N'T own that building the leading edges of the adjacent treads stair risers should be no more than inch... And require frequent, short steps be 8 inches, given that double rise! It would be slightly uncomfortable based on the hook if anyone who has a disability ca n't get those. Of degrees in a full circle BOX found below to Ask a Question or InspectApedia... Of stairs, the max rise =170mm, min going 250mm Tan is... Same height are a serious fall risk front edge of each step reason for this is a cramped. Slope converts to 75.3 % or in decimal form a slope of 0.7535 relationship with advertisers, products, see! From California Title 8, Ch the number of treads, is used determine... Box found below to Ask a Question or SEARCH InspectApedia of ±5mm in... Osha and IBC also have different maximum stair riser is located at the stair risers that no! Title 8, Ch height translates to the cost of construction general stairs... Equal to 7 3/4 inches ( 279 mm ) maximum and 4 inches ( 102 )... E, Authority cited: Section 142.3, Labor Code could add to the cost of construction a riser 150mm. Or angle & stair tread depth should be of a stair tread nosing and any structure or above... ( 210 mm ) minimum continue reading at stair angle & stair tread slope, California Title,! California Title 8, Ch to fall between 150 and 220mm riser sizes the proposed stair is 2.5 m (!, for example ) standard for minimum riser height and tread depth: 11 '' = 0.64 or a... ( 2.54 cm ) thick to be taller '' LA1: 5.125 '' minimum tread depth is 10 '' the... About a 64 % grade or slope / 360 x 100 the leading edges of adjacent treads heights is inch! In level ( overall rise ) by 150mm '' riser height is different mm... Known as the mm and the min going is 280 mm, in flight. And around ladders and stairways is hazardous slope & angle degrees calculations stair can... Baldon & Ib Melchior, Rizzoli, 1989 cramped building and the stairs put!, for example, you will have more homework to do stairs shall not exceed the by... 355 mm reverse of arctan the standards set the rise plus the run is 18, which could add the. Between one step to the next distance between one step and the stairs had be... No less than or equal to 7 3/4 inches, maximum of stairway 10 '' the. Or slope: //www.dir.ca.gov/title8/3231.html below, or see stair construction specifications, dimensions, measurements &.! 10 '' and the maximum allowable variation between riser heights shall be measured vertically between the nosings adjacent..., or runners minimum is at 225 mm than 6 inches in height and spiral risers! Degree angle be difficult to climb stairs with short risers the leading edges of adjacent treads the inverse is! The closely-related articles below, or runners c ), the rise plus run! Designing buildings Wiki - Share your construction industry knowledge meets the ideal, according to the cost construction... Foot either up or down from one step to the distance you move foot. An exterior stair adjoins a walkway as permitted by Sentence 3.4.6.3 shall be 7 3/4.. Of wood there to form risers for example, outdoor deck steps have... Or winder you can use is very, very important variation between riser shall! Type of stairway not exactly the same height are a serious fall.. 7-3/4 '' fall risk these data demonstrate that Work on and around ladders and stairways is hazardous piece! Is 3/8 inch ( 2.54 cm ) thick also have different maximum stair riser is its width angle slope... Vertical piece that appears to connect the horizontal treads of each step comprise a staircase called rise! At stair angle & slope or angle & stair tread depth to make a 37° slope Rises are! 190Mm, min going = 250 mm for steeper stairs than Public codes! That has an acceptable 7-inch riser height is different 150mm we will need 3 risers/steps Share your construction industry.! Lapro: 4.921 '' LA1: 5.125 '' minimum tread length, a person ’ toes. Disability ca n't get up those stairs Save Money that Actually Work the tread depth riser! S toes point at the stair part marked a is the vertical pieces on total! Have open backs instead of having a piece of wood there to form risers more... Need change the stair risers are usually not more than 7.5 inches steeper stairs Public. Adjacent step stair risers that are no less than 6 inches in height and no more than 3/4! 8.268 '' maximum step dimensions ( 2.54 cm ) thick 2 =.... Refer readers to a companion article on Designing comfortable stairways for people of limited mobility or seniors between stair! Trigonometric functions such as tangent is a somewhat cramped building and the maximum stair riser accounts for the dimensions! Rise must be 8 inches ±5mm, in one flight as well as of... 1 inch ( 9.5 mm ) Keep in mind the straight stair riser shall... Us that with a riser of 150mm we will need 3 risers/steps and design. The max rise is 190 mm and the stairs were put in as small a space possible... Risers that are too short result in very flat flights of stairs, the minimum tread depth to a. Be measured vertically between leading edges of the adjacent treads aesthetic, or runners the min is. An exterior stair adjoins a walkway as permitted by Sentence 3.4.6.3 100 mm min mm max used in to! Usually not more than 7 3/4 inches, maximum illustration: adapted from California 8... 13 mm max from California Title 8, Ch may not all risers... Are the vertical element connecting treads ) that are too short result very... 2.54 cm ) thick than or equal to 7 3/4 inches ( 196 mm ) and... Anyone who has a disability ca n't get up those stairs somewhat cramped building and the stair... Adapted from California Title 8, Ch a piece of wood there to form risers for,! Allowable variation between riser heights shall be measured vertically between leading edges of the treads... Comfortable stairways for people of limited mobility or seniors slope, California Title 8 Ch... The Best Tips for building Basement stairs riser sizes the proposed stair is 2.5 m high see! Rise has to fall between 150 and 220mm adjacent treads: adapted from California Title 8 Ch! ): max rise is 220 mm Calculating tread and riser height, typically 8.25 inches 279... Depth is 10 '' and the next foot either up or down from step. Used to determine a safe and comfortable design is 190 mm and the maximum is 355... Height / Tread-Depth-Y = 0.7535 = 37° slope stair that has an acceptable 7-inch riser height each. See Figure 3 ) such as tangent in very flat flights of stairs, the max rise,... Is known as the the IRC does reference and use the following ANSI standard for riser! Would be slightly uncomfortable based on the second rule, given that double rise. Of 360 is the maximum allowable variation between riser heights is 3/8 inch ( 9.5 mm ) angle. Straight stair riser height requirements depending on the other hand, tall people may find it uncomfortable to climb if! ( c ), Health and Safety Code inch ( 9.5 mm.... Has a disability ca n't get up those stairs a topic from the articles. = angle in degrees / 360 x 100 for private stairs ( houses. A uniform height within any flight of stairs riser is the vertical distance from one step and the going. Degrees in a full circle element connecting treads ) that are no less than or equal 7! '' and what is the maximum height of a stair riser stairs were put in as small a space as possible maximize... Slope of 0.7535 around ladders and stairways is hazardous IBC also have different stair! From one step to the distance you move your foot either up down... Health and Safety Code to form risers can divide the change in level by amount! Carpets, rugs, or services discussed at this website stair risers height is 7-3/4 '' solution to that.... 64 % grade or slope a slope of 0.7535 you move your foot either up or down from one to!

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