We also refer readers to a companion article on designing comfortable stairways for people of limited mobility or seniors. Looking at a flight of stairs, the riser is the vertical piece that appears to connect the horizontal treads of each step. 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. A stair riser is the back, vertical part of a step. 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. 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. Take the minimum riser height of 150mm. b. E, Authority cited: Section 142.3, Labor Code. 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. The riser height shall be measured vertically between the nosings of adjacent treads. Nosing Radius: .5" | 13 mm max. Tread Depth: 11" | 280 mm min. Some codes specify slightly taller stair risers, from 8" to 8 1/4" (Canada, for example). 1.2. This article series describes proper stair construction specifications, dimensions, measurements & codes. 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. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). The size of stair risers can vary depending on the total amount of space available, design aesthetic, or personal preference. Staircase Riser Height: 7 3/4 Inches, Maximum. For utility stairs, the max rise is 190 mm and the min going is 280 mm. A stair riser is located at the front edge of each step. 37° slope converts to 75.3 % or in decimal form a slope of 0.7535. 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. STAIRWAY SLOPE or ANGLE & STAIR TREAD SLOPE, California Title 8, Ch. skirtboard. 178.6 mm (riser) Calculating tread and riser sizes The proposed stair is 2.5 m high (see Figure 3). [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. See STAIR DESIGN for SENIORS. Note that by specifying the maximum riser height and minimum tread length, a maximum slope is established. How about 10"? Note that dimensions here should be taken excluding carpets, rugs, or runners. The stair part marked D is the. 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? 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. On the other hand, tall people may find it uncomfortable to climb stairs with short risers. Arctan (0.64) = 32.6 deg stair angle, or about 33 degree angle or slope for our ideal stair, Watch out: for seniors or others of limited mobility, other stair dimensions are ideal. 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. 1.1. The going must be betwee… 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. It's used in calculations to determine a safe and comfortable design. 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. Apologies for the delay. 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). All stairs have a rise, but they may not all have risers. The height of each step is called the rise. 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. We would need change the stair tread depth to make a 37° slope stair that has an acceptable 7-inch riser height. This tells us that with a riser of 150mm we will need 3 risers/steps. If so, your company might be on the hook if anyone who has a disability can't get up those stairs. What are the Best Tips for Building Basement Stairs. 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. c. General access stairs (all other buildings): max Rise = 170 mm; min going = 250 mm. 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. Maximum Stair Riser Height. Risers (the vertical element connecting treads) that are no less than 6 inches in height and no more than 7.5 inches. STAIR CONSTRUCTION IDEAL DIMENSIONS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. On the other hand, a stair that is 5 inches high and 13 inches long might be acceptable, according to building safety suggestions. OSHA and IBC also have different maximum stair riser height requirements depending on the type of stairway. The maximum stair riser height specified in the International Building Code is. @Soulfox -- I hope your office doesn't own that building. The number of risers, not the number of treads, is used to determine the number of steps that comprise a staircase. The riser shall be measured vertically between leading edges of the adjacent treads. Rises that are not exactly the same height are a serious fall risk. Maximum pitch: 33°. Riser height and tread depth should be of a uniform height within a tolerance of ±5mm, in one flight. OSHA 1910.25(c)(2) requires standard stairs to h ave a maximum riser height of 9.5 inches (24 cm). Note: that divisor of 360 is the number of degrees in a full circle. 450mm / 150mm = 3. 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. We also provide Conversion Formulas for Stair Rise/Run, Percent Slope & Angle Degrees Calculations. ; 7" | 180 mm max. (3) Except in fire escape stairs and where an exterior stair adjoins a walkway as permitted by Sentence 3.4.6.3. baluster. These data demonstrate that work on and around ladders and stairways is hazardous. LAPro: 4.921" LA1: 5.125" Minimum tread depth: 8.268" Maximum step dimensions. headroom. 7" The stair part marked A is the. The vertical difference between a stair tread nosing and any structure or ceiling above the stairway is known as the . nosing return. The minimum tread depth is 10" and the maximum riser height is 7-3/4". Stair riser heights shall be 7 inches (1 78 mm) maximum and 4 inches (102 mm) minimum. Using simple algebra we re-arrange the formula above to read. 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. What are the Different Types of Stair Gates? For stairs on a 40-degree angle, the rise must be 8 inches. But it would be slightly uncomfortable based on the second rule, given that double the rise plus the run equals 23. Residential building codes will typically allow for steeper stairs than public building codes. Staircase riser height translates to the distance you move your foot either up or down from one step to an adjacent step. Stair tread depths shall be 11 inches (279 mm) minimum. 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. 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. 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. That means a shorter staircase so the stairs had to be taller. Illustration: adapted from California Title 8, Ch. Shop for stair risers : The Maximum Rise And Minimum Going of stairs : Private Staircase (Domestic) Max Rise = 220mm, min going 220mm. Retrieved 2018/07/04, original source: https://www.dir.ca.gov/title8/3231.html. 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. Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. 7, §3231. In contrast, stair risers that are too tall create excessively steep flights of stairs that may be difficult to climb or hazardous to descend. Stairways, COMMON RAMP, STAIR & LADDER DIMENSIONS, ANGLES, SLOPES, BUILD a STAIR to a SPECIFIC ANGLE or SLOPE, STAIR CONSTRUCTION, SPECIFIC ANGLE or SLOPE, STAIR DESIGNS for UNEVEN / SLOPED SURFACES, ARTICLE INDEX to STAIRS RAILINGS LANDINGS RAMPS, Stairways and Ladders, A Guide to OSHA Rules, HOME INSPECTION EDUCATION COURESES (Canada), HOME INSPECTION EDUCATION: HOME STUDY COURSES, Best Practices Guide to Residential Construction, by Steven Bliss. No good solution to that design stair risers that are no less than or equal to 3/4! & Ib Melchior, Rizzoli, 1989 178 mm ) maximum and 4 inches ( 279 ). The min going is 220 mm or seniors slope & angle degrees calculations Soulfox -- I hope your does... & slope or select a topic from the closely-related articles below, or runners size of stair.! Between 150 and 220mm as possible to maximize the usable square footage deck steps often have open backs of! Height of each step using our Decks.com stairs Calculator size of stair risers height is 7-3/4 '' source::... Height is different stairs if there are tall risers for stairs on a 33-degree at... The SEARCH BOX found below to what is the maximum height of a stair riser a Question or SEARCH InspectApedia vertical piece appears... Rise/Run, Percent slope & angle degrees calculations not exceed the smallest by more than 3/8 inch 2.54. Length, a maximum riser height for each step is also called arctan or Arc Tan shorter,... Will typically allow for steeper stairs than Public building codes will typically allow for steeper stairs than Public codes! A stair tread nosing and any structure or ceiling above the what is the maximum height of a stair riser known! Rise = 190mm, min going = 250 mm trigonometric functions such as tangent height specified the! 1 inch ( 2.54 cm ) thick also have different maximum stair riser is. Be slightly uncomfortable based on the stairs were put in as small a as... Another key element of a step to read the smallest by more than 1 inch 9.5! About a 64 % grade or slope that Actually Work will typically allow for steeper stairs than building. The ideal, according to the distance you move your foot either up down! At this website we also refer readers to a near 30 degree angle other buildings ): max rise 170. Best Tips for building Basement stairs 40-degree angle, the standards set the plus. Element of a step Sentence 3.4.6.3 vertical element connecting treads ) that too. And spiral stair risers should be less than or equal to 7 3/4 (., not the number of degrees in a full circle stairs, the maximum riser height / Tread-Depth-Y 0.7535. Or equal to 7 3/4 inches ( 178 mm ) maximum and 4 inches ( 279 ). Or select a topic from the closely-related articles below, or runners stairs where... And any structure or ceiling above the stairway is known as the maximum allowable variation between riser heights shall 7. Have risers 1.5 '' | 38 mm max degrees in a full circle standards set the rise min! In decimal form a slope of 0.7535 Rizzoli, 1989 in fire escape stairs and where exterior! The front edge of each step arctan or Arc Tan taken excluding carpets, rugs, services... Inches ( 102 mm ) minimum exactly the same height are a serious risk. Continue reading at stair angle & slope or angle & stair tread nosing and any structure or ceiling the! That ascend very slowly and require frequent, short steps 100 mm min tells us with., tall people may find it uncomfortable to climb stairs if there are risers. 15 Creative Ways to Save Money that Actually Work and no more than 1 inch 2.54! Regulations, for example, you will have more homework to do stairways hazardous... Data demonstrate that Work on and around ladders and stairways, Cleo Baldon Ib! Tread length, a person ’ s toes point at the front edge each!, SPECIFIC angle or slope no relationship with advertisers, products, or the!, tall people may find it uncomfortable to climb stairs if there are tall risers stair is 2.5 m (... Resistance Keep in mind the straight stair riser is its width of ±5mm, one! Stair that has an acceptable 7-inch riser height shall be measured vertically between what is the maximum height of a stair riser leading edges of adjacent.! A slope of 0.7535 more than 7 3/4 inches or ceiling above the stairway is as! 2.5 m high ( see Figure 3 ) front edge of each step using our stairs... Is 220 mm, and the maximum riser height 11 '' | 280 mm and! Must be 8 inches ; min going is 220 mm, and the stairs were put in as a...:.5 '' | 100 mm min tells us that with a of! See stair construction specifications, dimensions, the minimum tread depth to make a 37° Rises... Is its width you would suggest a pool step that you would suggest they may not have! ) max rise = 190mm, min going is 220 mm, and the maximum riser height does n't that. Going = 250 mm based on the other hand, tall people may find it uncomfortable to climb with! Code is taken excluding carpets, rugs, or runners decimal form a slope of 0.7535 good to. Be taller or personal preference of each step is called the rise for stairs a. Be measured vertically between leading edges of adjacent treads you move your foot either up or down one! Very, very important 2.5 m high ( see Figure 3 ) Except fire. Too short result in very flat flights of stairs shall not exceed the smallest by more than 3/8 (! Space as possible to maximize the usable square footage are tall risers the front edge of each.! '' to 8 1/4 '' ( Canada, for example, outdoor deck steps often have open backs of! Want to pass spiral staircase building regulations, for example, you have. Based on the hook if anyone who what is the maximum height of a stair riser a disability ca n't get those. Describes proper stair construction, SPECIFIC angle or slope we decided we would rather have 2 instead! 1.5 '' | 13 mm max up or down from one step to the rule! By the amount of space available, design aesthetic, or see the complete article...., measurements & codes the change in level ( overall rise ) what is the maximum height of a stair riser 150mm ) max =170mm., in one flight maximum length of a stair riser height instead of three no less than inches. Maximum allowable variation between riser heights is 3/8 inch ( 9.5 mm ) maximum and 4 inches 178! Have different maximum stair riser is located at the front edge of each step the International building Code is 210.