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What are Tiny House Stair Sizes? (Explained)

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Tiny house stair sizes explained

Adding a second floor to your tiny home can be a great way to create additional living space.

Still, you’ll need to ensure that you get the stair design just right for your comfort and safety, as well as its impact on the overall aesthetic of your home.

In this article we cover what your tiny house stair size should be, the dimensions and exact width you will need. 

If you’re building your own tiny house, we’ll also explain how to calculate the right stair dimensions.

What are tiny house stair dimensions?

For a standard tiny house staircase, you’ll need a minimum width of 20 inches below the handrail and 17 inches above the handrail. The overall size of the stairs takes up, on average, around 20 to 25 square feet.

Some people opt for a more compact staircase to save space in their tiny home, but you must get the tread and riser proportions correct for the comfort and safety of everyone in your home.

The tread needs to be around 20 inches minus 4/3 of the riser height.

And the riser height should sit between 7 and 12 inches.

These measurements are crucial in making your stairs functional.

Sometimes, you’ll have to make the stairs more compact to fit in with your tiny house design plans. The Mac Shack design by Rocky Mountain Tiny Houses is only 14ft long, so it doesn’t have the luxury of a sweeping staircase. Instead, the compact staircase allows for a second floor that is easy to access and provides an additional sleeping room.

When designing your tiny house staircase, you’ll want to ensure that the steps are a manageable height and that the depth is large enough to accommodate your foot.

In addition, you’ll want to keep the stairs are uniform as possible to avoid tripping over the varying heights.

How wide are tiny house stairs?

The minimum width of stairs in a tiny home should be 20 inches.

The idea of a tiny home may conjure up images of a loft and ladder combination, but as more people turn to this off-grid living style (including children and older people), stairs are gaining much greater popularity.

Tiny house stairs provide easier access to loft areas and create additional storage space. They can add visual appeal to make your small house feel more like a home, and you don’t have to worry about finding a storage area for your ladder.

Like everything else in your tiny home, you must ensure that your stairs meet the minimum requirements in your jurisdiction to ensure your safety and security.

When installing stairs for your tiny home, ensure the minimum width is 20 inches. Meanwhile, the height of your steps should sit between 7 and 12 inches.

How to calculate stair size for your tiny home

To work out the riser height, use the following calculation:

Riser height = height from floor to loft / (the number of steps + 1)

To work out the tread length, use the following calculation:

Tread length = length of the stair run / number of steps

To save space in your design, you can also use an alternating tread step, like this design by Rocky Mountain Tiny Houses.

Tiny house staircase with alternating tread step

It’s not always easy to work out how many steps you’ll need, so you may have to experiment with a few different numbers before finding the right combination of riser height and tread length.

To help you calculate the correct number of steps, follow the tips below:

  • Calculate the distance from the ground floor to the loft.
  • Decide how tall you would like your tread to be (for example, 10 inches), then divide ground to loft distance by this number. That is how many steps you will need.
  • For example, if there is 6ft between the ground and floor level and you want a tread of 10″, the calculation would be:
    • 72″/10″ or 7.2 – meaning you’ll need a minimum of seven steps.
  • Work out how much room you can spare for your stair run. A shorter run may save space, but it is much harder to climb, especially for people with knee problems. A longer run is far more desirable, but it depends on your home design and space availability.
  • Divide your run length by the desired number of steps to work out the tread depth of each step.
  • For example, if you have an allocated run space of 4ft and seven steps to accommodate, the calculation would be:
    • 48″/7 or 6.85 – your tread depth will sit at 6.85.”
  • From there, you can determine whether the tread depth is sufficient.

Spiral staircases can save space on your build, but they are often much harder to design. Each step needs a minimum width of 26″, the tread depth needs at least 6.75″, and the riser should be a minimum of 9.5.”

When you begin your staircase build, you’ll start by estimating the measurements of the treads and riser, then match your design to your space requirements.