Spiral Staircase Dimensions (with Drawings)

Spiral staircases are an elegant way to dress up your home and many people prefer to display them in an open space. You can use them for attics, porches, two-story libraries, study rooms or simply as a functional staircase to a second floor. However, the dimensions of spiral staircases can vary depending on the style and location.

Spiral staircases measure 9 feet in overall height and range from 48 to 54 inches in diameter or width, although some styles can be wider. Most spiral stages are angled at 30 degrees and each stage rises between 4 inches and 7 inches. The handrail must be 30 to 34 inches above the top of the tread with a width of 1-¼ to 2 inches.

People often choose spiral staircases for their aesthetics, but they are also very functional. They can be an effective space-saving alternative to traditional steps and feature versatile designs. Curved and circular stair dimensions are alternatives to spiral staircases that share similarities and differences.

Dimensions of the spiral staircase

The dimensions of a spiral staircase can change dramatically depending on the designer’s preference. Their height depends on the height of the second floor or opening they need to reach. Their width can be smaller if it is a narrow staircase, or much wider if it is in an open space.

Determining the height dimensions for spiral staircases

Because people use spiral staircases for lofts, two-story studies, or outdoor porches, their typical height is difficult to define. The height of the adjacent upper floor is the determining factor for the stair height.

However, many homes have rooms with a typical floor-to-ceiling height of 8 feet. When measuring for a spiral staircase, it is important to measure from floor to floor, not floor to ceiling. In an 8-foot room, a spiral staircase is 9 feet tall because it goes through the space between floors.

Spiral staircase diameter dimensions

Similar to the height, the diameter (or width) of a spiral staircase can vary greatly depending on the design. If the spiral staircase is located in a cutout, niche or hole in the ceiling, then it has a limited diameter. However, if the staircase is on the side of a house that connects two levels of the porch, its diameter can be larger.

They measure standard diameters of spiral staircases in 6 inch dimensions, e.g. e.g. 48″, 54″ and 60″. Typically, spiral staircases are no less than 3 ½ feet in diameter, but can be as wide as 6 feet. Diameter measurements are shown as 48″x48″ and 54″x54″.

You determine the walking area by the width of the stairs. On spiral staircases, every 6 inches in diameter equals 3 inches of walking space. The diameter of a 5 foot spiral stair is similar to the walking area of ​​a standard stair.

Spiral staircase opening and platform dimensions

If you have a round hole in your ceiling for a spiral staircase, it’s called a well opening. A well opening must be at least 2 inches wider in diameter than the diameter of the spiral staircase. For example, a 54″ x 54″ diameter well opening cannot accommodate a stair diameter larger than 52″ x 52″.

Landings are the entry and exit points of the spiral staircase. The platform width measurement is half the diameter of the stair, if not larger. This allows the staircase to transition seamlessly from entrance to exit.

Spiral staircase profile dimensions

The step dimensions of the spiral staircase depend on the diameter of the staircase. Both tread depth and width increase as the stair diameter increases.

The tread is the measurement from the front of the step to the back. Since the steps of spiral staircases are sharply angled, measure them near the middle of the step. Spiral stair treads must be no less than 7 ½ inches when measuring 12 inches from the center of the stair.

The riser height is the height from the top of one step to the top of the next. The minimum riser height in a spiral staircase is 9 ½ inches. The step heights in spiral staircases can be steeper than in other types of stairs.

Read more about tread materials and prices here.

Spiral Staircase Handrail Dimensions

All spiral staircases should have a handrail the full height. The handrail must be 30 to 34 inches above the tread. Additionally, it should be 1 ¼” to 2″ wide for support.

Handrail posts should be spaced a maximum of 4 inches apart to protect children. Railings should encircle the raised platform at the top of the spiral staircase and connect to the handrail. Railings must be at least 42 inches high from the ground to the top of the railing.

If you want to learn more about which colors to choose when painting your handrail or railing, you can read about it here.

Spiral staircase column dimensions

Spiral staircases wind around a central pole called a pillar. This column will be the central support for a spiral staircase, since spiral staircases do not have stringers.

Stair columns can range from 5″ to 10″ in diameter, but ultimately depend on the design of the stair. The overall height of the column extends from the finished floor to the floor of the upper platform. Some pillars will extend through the platform and act as posts as part of the railing.

Curved stair types and dimensions

Curved stairs are another stair option that is similar to a spiral staircase. People enjoy spiral staircases as they add a sense of grandeur to the space they occupy. Spiral staircases are more eye-catching than purely practical, but they serve just as functionally as a traditional staircase.

Curved vs Spiral Stairs

Spiral staircases and spiral staircases are similar in that both are rounded rather than straight like traditional staircases. However, there are key differences between the two.

The pillars of the spiral staircases serve as the primary architectural support. Curved stairs are independent of columns and instead have two stringers with steps connecting them. These stringers resemble those of a traditional staircase; only they are rounded or curved.

Because of this construction, curved staircases do not offer the space saving advantage that spiral staircases do. While spiral staircases usually only take up vertical space, curved staircases take up a lot of vertical and horizontal space.

Dimensions of the curved staircase

For any staircase, the height of a curved staircase depends on the distance between the bottom floor and the top floor. You should measure the height of a curved staircase from the bottom finished floor to the top of the top finished floor.

In a standard room with an 8 foot ceiling, a sweeping staircase is 9 feet high. However, many people who place curved staircases in their homes place them in larger spaces, such as grand entrance halls. In such a space, a sweeping staircase can be closer to 10 to 15 feet tall.

A standard spiral stair has a width of 36 inches across the face of the step. Railings and posts on either side of the stair can add 10 to 20 inches to the width.

By regulation, the stair step height must be a minimum of 4 inches and a maximum of 7 inches.

The top platforms of curved stairs must have 10 feet of clearance above the top step. Since many curved stair bases start in larger rooms, this shouldn’t be a problem. However, keep this in mind if you are planning for the staircase to lead to an upper hallway.

Circular vs Spiral Stairs

Spiral staircases are referred to as spiral staircases by many people. While spiral staircases are certainly circular, actual spiral staircases refer to a type of curved staircase.

Spiral staircases are similar to curved staircases in many ways. They are based on stringers rather than columns and serve a similar function to traditional straight staircases.

However, spiral staircases are very different from standard curved staircases. Spiral staircases have both the entry and exit points at the same angle and meet in the same vertical plane. They have a regular “U” shape.

Dimensions of the spiral staircase

The dimensions of spiral staircases are in many ways similar to standard spiral staircases. They range in tread height from 4 inches to 7 inches, a standard width of 36 inches, and a platform spacing of 10 feet.

However, spiral staircases have a specific radius dimension. A spiral staircase should have a minimum radius of twice the width of the staircase. For example, if the stair was 36 inches wide, the radius should be 72 inches.

Also, the inside tread depth on a spiral staircase should be at least 10 inches. The outer profile depth of each staircase is slightly longer than the inner one.

in summary

Spiral staircases are beautiful elements in a home. They are not only aesthetically pleasing but also practical. They are as solid as a traditional staircase and take up much less space than a staircase.

In general, a spiral staircase has an overall height of 9 feet and a diameter or width of 48 to 54 inches. They are usually angled at 30 degrees, with steps increasing between 4″ and 7″. The dimensions of spiral staircases change a lot depending on the room they are in, so make sure you get the exact dimensions.

Stairs don’t have to be boring, and you may want a more elegant staircase in your home. Spiral, curved, and circular all bring unique design characteristics to the table, and each is useful in specific design circumstances. Have fun choosing the strain that works best for you!

Stacy Randall

Stacy Randall is a NOLA wife, mother and freelance writer who has always had a passion for DIY projects, home organization and room beautification. Together with her husband, she has spent the last few years lovingly renovating her grandparents’ former house and making it her own, while learning a lot about life in the process.