Overview
In this lesson, students explore techniques for creating several types of common circulation elements for multistory buildings, including stairs, elevators, and ramps. They will learn how to:
- Create simple examples demonstrating circulation techniques.
- Edit and customize elements as needed to model more complex conditions.
- Add railings at floor edges and around floor openings.
Creating Simple Stairs and Ramps
Figure 1.4.1. Stair elements—treads, risers, stringers, and railings
As shown in Figure 1.4.1, stairs are typically composed of many elements, including:
- Treads―the the horizontal surfaces that you step on.
- Risers―the vertical surfaces between the treads.
- Stringers―the supports for the treads and risers, which can be located at the sides of the stair or in the center (underneath the treads and risers).
- Railings―on one or both sides of the stair.
Using Autodesk® Revit® software’s Stair tool, specify a few key characteristics, and Revit automatically creates a stair with all of these elements.
The simplest way to create a stair is to:
- Specify the essential properties that set the height and length of the stair―the levels of the top and bottom of the stair.
- Sketch the run line―an imaginary line that specifies the direction and length of each stair section.
Revit automatically calculates the number of risers required to connect the top and bottom levels and reports the number of risers created as you sketch the run line.
Ramps are created in a similar way using the Ramp tool, which also appears in the Circulation panel of the Home tab:
- Specify the top and bottom levels.
- Sketch the run line.
Revit automatically calculates the length of the ramp required using a slope of 1/12 for accessibility, but you can customize this slope as needed.
Modeling Custom Stair Shapes
You can change a stair in many ways to fit your requirements and the space available:
- Use the Move or Rotate tool to reposition or reorient the stair.
- Alter the stair properties (for example, the number of risers, tread length, or stair width) in the Properties palette.
- Edit the sketch that defines the stair’s layout to change the boundary shape or the placement and shape of the risers.
You can also sketch curved run lines to create curved or spiral stairs. When creating spiral stairs, keep in mind that a curved stair run is limited to a rotation of 360°. If you need to model a stair with greater rotation, create several segments, then move and join them to create a continuous run.
Modeling Floor and Ceiling Openings and Adding Railings
While the Stairs tool automatically creates all of the stair elements needed to connect between two levels, it does not cut openings in the floors or ceilings that separate those levels. You can create these openings in two ways:
- Use the Edit Boundary tool and adjust the floor or ceiling boundary sketch to include the layout of the opening.
- Place a vertical opening or shaft opening element.
When creating stairs and ramps, Revit automatically adds railings to these circulation elements for safety. You can use the Railings tool to adjust these railings or add new ones in locations where they are needed:
- Around floor openings
- At exposed edges of floors and balconies
Modeling Elevators and Shafts
Modeling an elevator in the Revit software requires several steps:
- Placing an elevator component
- Creating a vertical shaft to cut openings in floors and ceilings
- Adding walls around the elevator shaft
- Cutting openings in the shaft walls for the doors on each floor
If an elevator component is not included into your model, you can load one from an external library.
The Shaft Opening tool is especially useful for modeling elevators because it can cut a vertical opening through many floors, ceilings, and roofs. When you move or modify the boundary of a shaft opening, the changes are automatically updated on every level.
Learning Objectives
After completing this lesson, you will be able to:
- Determine the necessity of circulation elements in a structure and evaluate various options.
- Explore the architectural and spatial advantages of creating stairs of different shapes and sizes.
Tutorials
Creating a Stair and Ramp
In this exercise, you will learn how to:
- Create stairs by sketching run lines.
- Flip a stair direction and move a stair into place.
- Create stairs with multiple runs and complex layouts (for example, L-shaped,U-shaped, and curved stairs).
- Create and modify ramps.
Figure 1.4.2. Sketch of the run, boundary, and riser lines for an L-shaped stair
Student Exercise
- Create a new stair from the first floor of the studio to the second floor meeting space using Figure 1.4.3 and the view called Studio – Stair 3D as guides.
Figure 1.4.3 - Stair from first to second floor in the studio
- Create an L-shaped ramp with two runs and no railings connecting the deck at the first floor level to the parking area, which is 1'–9"(0.53 meters) below ground level, using Figure 1.4.4 and the default 3D view as a guide.
Figure 1.4.4 - Ramp from the concrete deck to the parking area
Modeling Custom Stairs
In this exercise, you will learn how to:
- Edit the sketch to change the stair boundary and shape of the risers.
- Change stair and rail types.
- Modify the steepness of a stair by adjusting the settings in the Properties palette.
- Create and edit a spiral stair.
Figure 1.4.5. Sketch of the modified boundary and riser lines for a custom stair layout
Video Tutorial
Student Exercise
- Replace the stair created in the previous exercise with a new steeper stair with only 16 risers:
- Open the Stairs tool, edit the type properties, choose the Residential – Open Riser type, duplicate it, and rename the new type Residential – Open Riser – Steep.
- Set the properties for this new type to allow a maximum riser height of 9" (0.23 meters) and a minimum tread depth of 9" (0.23 meters) then create a new stair using this type to replace the old one.
- Change the railing on the stair to Handrail – Pipe.
- Create a spiral stair with 15 risers and run radius of 2'-0" (0.6 meters) to connect the first and second floor of the residence:
- Open the Stairs tool and duplicate the Residential – Open Riser type again, renaming the new type to Residential – Open Riser – Spiral.
- Set the maximum riser height to 10" (0.25 meters) and the minimum tread depth to 11" (0.28 meters).
- Using the curved run line option, try sketching a spiral stair using this type. The sketch cannot be completed, because the rotation required exceeds 360°.
- Change the instance properties for this stair to set the Actual Tread Depth property to 10" (0.25 meters). This value will override the minimum value specified in the type properties.
- Resketch the spiral stair using these new properties and move it to the location shown in Figure 1.4.6.
Figure 1.4.6 - Placement of spiral stair in the residence
- Change the spiral stair’s railing to Handrail – Pipe and add a center pole as shown in Figure 1.4.7 using the views First Floor – Spiral Stair and Second Floor – Spiral Stair as guides.
Figure 1.4.7 - Spiral stair with pipe railing and center column
Creating a Floor Opening
In this exercise, students will learn how to:
- Cut an opening to allow stairs to pass through floors.
- Calculate the head height of stairways.
- Modify floor openings.
- Create railings.
- Modify the physical properties of railings.
Figure 1.4.8. Adding railings around floor openings
Video Tutorial
Student Exercise
- Create an opening in the second floor of the residence at the top of the spiral as shown in Figure 1.4.9 and add railings of the type Guardrail – Pipe as shown in Figure 1.4.10.
Figure 1.4.9 - Floor opening for spiral stair
Figure 1.4.10 - Railing around opening
Creating an Elevator
In this exercise, you will learn how to:
- Place an elevator component.
- Add walls to enclose the elevator.
- Cut an elevator shaft that spans all levels.
- Provide openings in the shaft walls to access the elevator at each floor.
Figure 1.4.11. Placing an elevator component and walls to enclose the shaft
Video Tutorial
Student Exercise
- Place the Electric_Lift elevator component in the studio near the stair placed in an earlier exercise.
- Add 6" (0.15 meters) generic walls to the first and second floors as needed to enclose the elevator with shaft walls.
- Use the Shaft Opening tool to cut an opening from the first floor to the roof within the shaft walls and place wall openings on the south shaft wall to provide access to the elevator.
- Add a guardrail at the edge of the second floor slab between the west exterior wall and the new elevator shaft walls. Use the view Second Floor – Elevator to see the progression of the elevator.
Figure 1.4.12 - Finished elevator with opening in shaft wall
Assessment
Creating Simple Stairs and Ramps
- How does changing the riser height affect the number of risers required and as the number of risers changes, what happens to the overall length of the stair?
Increasing the riser height decreases the total number of risers needed since each step provides a larger gain in elevation. If we assume a constant tread depth, the total length of the stair decreases. This method essentially increases the slope of the stair.
- If you need to shorten (or lengthen) the total run of a stair, which properties can you change to accomplish this?
To shorten a stair, increase the riser height and decrease the tread depth. To lengthen a stair, decrease the riser height and increase the tread depth.
- What are the required properties of a wheelchair-accessible ramp as specified by the Americans with Disabilities Act?
The ADA defines regulations for ramps in section 4.7 and 4.8 of their Standards for Accessible Design. In general, the maximum slope for a ramp in new construction is 1:12 with a clear width of 36 inches (0.91 m).
Modeling Custom Stair Shapes
- What is the typical relationship between tread length and riser height in a single family residence? For an exterior stair? Explain the difference.
Interior stairs in a typical residence typically have a riser height of about 7.25 inches (0.18 m) tall with a tread length of about 11 inches (0.28 m). For comfortable and safe use, the riser height and tread length should maintain the relationship: 2*Riser Height + 1*Tread Length = 25–26" (0.64 to 0.66 m). Building codes in the United States limit the riser height to no more than 8 inches (0.20 m).
Exterior stairs are typically designed with a shorter riser height and a longer tread length to create a shallower slope. This reduction is appropriate for exterior conditions which are often slippery or wet.
- What is the maximum riser height and minimum stair width allowed by today’s building codes?
Except for spiral stairs and winders, risers may not exceed 8 inches in height measured vertically from tread to tread. Treads shall be at least 9-inches wide measured horizontally from nosing to nosing.
Modeling Floor and Ceiling Openings and Railings
- How much clearance is required between the treads of a stair and the floor above (so users do not bump their heads)?
The required clearance between the treads of a stair and the floor above varies slightly based on the building code used. Typical values are 76 to 80 inches (1.93 to 2.03 m).
- What can you do to a floor opening to increase the clearance provided?
You can enlarge a floor opening to increase the clearance between the floor and the treads of the stair below.
- What are the key differences between a handrail and a guardrail?
Handrails are generally defined as being used for guidance and support while the purpose of guardrails is to resist accidental falls. Handrail heights are commonly between 34" (0.86 m) and 38" (0.97 m), while guardrails are 42" (1.07 m) in height. There is often a requirement that a guardrail have a handrail included as well.
Handrails are required on stairs, and guardrails are required on balconies and around floor openings.
Modeling Elevators and Shafts
- What are the advantages and disadvantages of creating floor openings with shaft opening elements versus editing the floor boundary?
By using the shaft opening tool, Revit automatically creates an opening extending through multiple surfaces. This is convenient when multiple boundaries must be edited because it eliminates the need to do each one separately.
The shaft tool creates problems when different shapes need to be created or when a different floor must extend into the shaft region. If part of a new floor or roof passes through a shaft region, it will not be displayed.
- Why are stairs and elevators typically located very close to each other?
Both stairs and elevators are essential circulation elements and they must be easily located. If the elevators are nonoperational and in cases of emergency, the stairs should be easy to access from the elevator location.
It is also common to place elevators next to stairways since they both require continuous vertical shafts.
Key Terms
Key Term | Definition |
Treads | The horizontal surfaces of the stair that you step on. |
Risers | The vertical surfaces of the stair between the treads. |
Stringers | The supports for the treads and risers, which can be located at the sides of the stair or in the center (underneath the treads and risers). |