Spiral Staircase Dimensions & Sizes

Paragon Stairs provides spiral stairs that are safe and reliable, even at our smallest width. The smallest spiral staircase diameter we offer is 3’6”. This space saving spiral stair is perfect for the homeowner looking to maximize their square footage without sacrificing style or safety.

From there, Paragon’s diameters increase in 6” intervals. An International Building Code compliant spiral staircase must have at least a 5’ diameter. Our standard diameters range up to 6’ wide, but we are able to go much wider if your custom staircase calls for it.

Clear Walking Path represents the space that you have to walk up and down the stairs.

The best way to envision the clear walking path of a spiral stair is to use the Sliding Door test. If you have a sliding door in your home, slide it open 17 inches. 17 inches is the clear walking path of our smallest diameter 3’6”. As you increase spiral stair diameter in 6” increments, clear walking path increases in 3” increments. Here is a list of our diameter and their clear walking paths.

3’6” Diameter – 17 inch clear walking path
4’0” Diameter – 20 inch clear walking path
4’6” Diameter – 23 inch clear walking path
5’0” Diameter – 26 inch clear walking path
5’6” Diameter – 29 inch clear walking path
6’0” Diameter – 32 inch clear walking path

Determining the diameter that is best for you depends on a few variables including the intended use of the stair (will you be carrying items up and down the stair?), how much it will be used (daily, monthly?) as well as budget.

Keep in mind that no matter what diameter of stair you choose, the minimum finished opening for your stair should be at least 2” bigger than the stair itself.

For example, the smallest stair that we offer is 3 feet 6 inches in diameter. 3’6” translates to 42 total inches in diameter and therefore the MINIMUM opening size that you need MUST be 44 inches x 44 inches (44”x44”). You need at least 44”x44” opening because you’ll need two extra inches for your fingers to travel along the handrail as you walk up and down the stairs. The two extra inches ensures that there will be no finger pinch-points.

If you are putting your spiral through a hole in the floor, here is a quick guide on the MINIMUM opening that you will need for each Paragon diameter. The absolute smallest opening size we can work with is 44 inches x 44 inches.

3’6” Diameter (42 inches) – requires at least a 44 inch x 44 inch floor opening
4’0” Diameter (48 inches) – requires at least a 50 inch x 50 inch floor opening
4’6” Diameter (54 inches) – requires at least a 56 inch x 56 inch floor opening
5’0” Diameter (60 inches) – requires at least a 62 inch x 62 inch floor opening
5’6” Diameter (66 inches) – requires at least a 68 inch x 68 inch floor opening
6’0” Diameter (72 inches) – requires at least a 74 inch x 74 inch floor opening