How Big Is A Spiral Staircase?

Spiral staircases might be a viable option for your home. They take up less space than typical staircases and can be a unique part of the home's aesthetic. How can you decide if a spiral staircase would fit well in your home? We've researched the dimensions of spiral staircases to help you plan for the right fit. 

Spiral staircases generally range in size from 42" to 76" in diameter. The floor opening at the top of the staircase must be two-square-inches bigger than the staircase's diameter. Spiral staircases are also measured by their floor to floor height, footprint, walking space, and landing length.

We know this is a big decision, so we've organized the most important information for you. Keep reading for more details on how to measure for a spiral staircase, as well as other things to keep in mind when thinking about spiral staircases as a functional feature in your home.

Spiral staircase to second floor in hall of modern luxury apartment, How Big Is A Spiral Staircase?

Are spiral stairs practical? 

Spiral staircases are great solutions for small homes or apartments as a space-saving measure. They work well as a second way to access a certain level, potentially as a private entrance to a bedroom or suite. You might also consider a spiral staircase as a replacement for a failing set of stairs. If the stairs to your basement are falling apart, consider installing a spiral staircase.

These stairs might not work in situations where large items are moved up and down frequently. If this is the case, consider a normal staircase or an extra-wide spiral staircase. For more information on staircase sizes, check out "How Much Floorspace Do Stairs Typically Take?"

How do you measure for a spiral staircase?

Several measurements must be taken. Use a tape measure, get some help from a friend, or hire a professional to take the measurements.

Diameter or Footprint

The staircase's diameter is found by measuring all the way across the staircase, from railing to railing. It includes the pole or standard in the middle. 

The footprint of the staircase is found by doubling the diameter. For instance, a staircase with a diameter of 4' 6" would have a footprint of 54" x 54". This provides a square of space that ensures there is plenty of clearance around the staircase. 

The smallest standard diameter is 3' 6" (or 42" x 42" footprint), and the largest standard diameter is 6' (72" x 72" footprint). However, specialty staircases can be made outside of these dimensions. 

Entrance door and hall in luxury apartment. Spiral staircase. Modern interior in light tones.

Well opening

The well opening is the space that the staircase will require on the upper level. Essentially, it is the size of the hole that will need to be cut. This can be either square or round opening, depending upon your preference. The well opening should also have handrails to prevent people from falling down the staircase.

No matter the staircase's size, the well opening must be two-inches longer and wider than the diameter. So, if you want to install a staircase with a 4' diameter (48" x 48" footprint), the well opening must be 50" x 50". This provides plenty of clearance for the railing so that there is room to grasp it, even when it meets the ceiling.

Floor to Floor Height

The first measurement to determine is the floor to floor height of the place you'd like to put the staircase. This can be found by measuring from the top of the lower level floor to the top of the upper-level floor, including the subfloor. This will determine which staircase is right for you, how many steps it will have, and the slope of the staircase. 

Walking Space

Because the diameter is a measurement of the entire staircase, please note that this does not describe the staircase's walking space. The walking space is the distance from the center pole to the outer railing. For the smallest standard diameter -- 3' 6" -- there are 17" of walking space. At each six-inch increase in diameter, the walking space increases by three-inches.

Stair Diameter Walking Space
3′ 6″ 17″
4′ 0″ 20″
4′ 6″ 23″
5′ 0″ 26″
5′ 6″ 29″
6′ 0″ 32″

Landing Length

This is the measurement of space from the last step of the staircase. In addition to being two inches wider than the staircase, the landing length must be enough that users don't hit their heads on the ceiling. There also must be enough space for users to clear the stairway. Ensure enough space for the user to exit the stairway without running into a wall or sloped ceiling. 

How to choose a spiral staircase size?

Interior, wide open space of a duplex, parquet floor, dark spiral staircase

The diameter and walking space of the staircase should be based on your preferences and needs. Ensure that you have enough space for the footprint, plus enough space on the top level for the well opening. If this staircase is the only way to access that level, the stairs should be at least 5' in diameter for a walking space of 26". This is for fire safety purposes, allowing as many people as possible to exit quickly. 

This decision should also be based on how much space you'd like the stairs to take up. If you're looking to be as minimal as possible and it is not the only way to access a particular level, purchase the smallest diameter stairs.

If you are carrying large items up and down the stairs, you will find that a larger diameter is better. If the person using the staircase needs a wider berth when walking, make sure to take that into account. For details on how to decide where to place a staircase, read "Where Should Stairs Be Located In A House (And Can You Relocate Them?"

Can you move furniture up a spiral staircase?

Keep in mind that any furniture will need to fit through the well opening at the top of the staircase and within the walking space of the staircase. For these reasons, spiral staircases make it more difficult to move furniture and other large items than normal staircases. If the spiral staircase is the only point of access to a certain level, you should only install a staircase big enough to handle the necessary furniture.

When figuring out if you can move furniture up a spiral staircase, the most important dimension is the well opening. There are ways to move big pieces up the staircase even with a small walking space, but if it cannot fit through the well opening, another method will be needed. You can also determine if it is possible to take the furniture apart to fit through the well opening.

If there is no way to transport some of your bigger furniture up the spiral staircase, consider hiring a professional moving company. Make sure they know about the spiral staircase. Most moving companies have the ability to move large furniture into homes using hoisting equipment. 

Are spiral stairs safe?

Spiral staircases are very safe as long as appropriate precautions are put in place. For instance, a solid railing should be installed the entire length of the staircase. Additionally, there should be a railing around the well opening.

The best way to ensure that your stairs are safe is to have a professional install them. Some products offer DIY installation but only do it yourself if you are confident that you can follow the directions exactly. Be sure to check your local building codes to ensure spiral staircases are allowed and that the dimensions you've chosen are satisfactory.

One way to ensure that the staircase is as safe as possible is to pay attention to the degree of each step. Steps should be at least 30-degrees of a circle. This guarantees that each step is wide enough to be safe. 

In Closing

A spiral staircase might be the perfect addition to your home. Be sure to measure for the staircase's diameter or footprint, the height of the floor on the top level, and the well opening on the top level. Decide how much walking space and landing length you need, considering how often the staircase will be used and how often you will have to carry large items up and down it. Find a staircase with a 30-degree step and a railing to make it as safe as possible.  As always, don't be afraid to hire a professional contractor to help.

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