Have you ever been someplace where the stairs feel off for some reason? Some stairs are too high or too low, and in both cases, you might feel like you’re about to fall. And you can!.
There are codes and best practices to ensure the safety of your stairs. One of the most critical question in this regard is:
Is there a standard height and depth for stairs?
According to the International Residential Code, the maximum height of stairs must be 7.75 inches with an 11-inch run. The tread depth, or horizontal step, should not be less than 10 inches. IRC also requires the slope to be not more than 30 degrees.
These codes leave the guesswork out of how you should construct your stairs. However, you need to understand when and where the code is applied. For instance, the area can be too cramped or too low to apply these codes by the book. There are other best practices to make sure you are building safe and easy to use stairs despite the lack of room or height.
We will try to cover all those cases in this post.
Table of Contents
Is It Mandatory to Follow the Code?
While IRC is an international set of standards, it isn’t globally implemented by law. Even in the US, some states might include IRC standards to the local building codes, and some won’t.
Still, you should know that these standards are laid out by engineers and experts with decades of experience. The purpose of these standards is to ensure safety and maximum useability.
In short, following the codes is always a best practice.
Poorly built stairs are a safety hazard around your house. In the US alone, there are more than a million reported cases of stair related accidents every year. Most of these cases are a result of poor construction and design.
And two of the common defects leading to accidents and falls are related to height and depth:
Tread Depth – The tread depth is measured from the nose of the tread to the face of the riser. It’s the amount of room each step has to accommodate your foot. If the tread is too narrow, your foot might hang down ate the heel, and you can slip.
Riser Height – Riser height is simply the height of each step. The higher the riser, the higher you will need to lift your leg, which increases the chances of falling, especially for children, the elderly, and those with infirmities
Ideally, follow the code to keep your stairs safe and comfortable for everyone. If that isn’t possible for some reason, forget the numbers and focus on the range.
The Rules and Range
Sometimes the building doesn’t allow you to follow the IRC code. There are factors such as floor-to-floor height. You need to leave at least 6’8” headroom to make it feasible for the average adult.
To ensure better headroom adjustment according to the height of the room, many professionals follow two different rules:
The r+R Rule – According to this rule, the sum of the run and rise should be 18 inches. That is generally, what you get when you apply the 11-inch run and 7-inch rise, but this rule brings in a bit of flexibility.
The 2r+R Rule – In some cases, the above rule may not give you an acceptable range. In that case, the sum of the rise and twice the run should be 25 inches.
You have to see which rule works best for your home. Most professionals would try both calculations and see which fits the given area and height.
Other Important Factors
Slope is an important consideration and is calculated for the entire staircase, not just step by step. Individual steps shouldn’t be sloped, but sometimes people do leave a few degrees of inclination in each step to ensure the easy flow of water.
Ideally, the slope of your staircase shouldn’t be more than 30 degrees. Anything more than that will make your stairs dangerously steep. Steeper slope also needs a higher rise, which doubles the risk. Not to mention climbing that kind of stair is quite exhausting.
Height and depth consistency is another crucial safety factor. We tend to walk or climb stairs in autopilot mode. Our mind synchronizes with our feet, and the movement is almost involuntarily. In that mode, however, our mind will treat each step precisely like the previous one, and that doesn’t work when each step is a different height or depth. Your next step might be too small or too big, causing you to trip and possibly fall.
The Case of Spiral Stairs
Keep in mind that calculation for spiral staircases will differ from the ones described in this post. If you are looking for safe and easy to use stairs, spiral, or angled stairs are not the best option. But sometimes, they are more practical for areas with less horizontal space.
In these fancy staircases, steps are usually narrower at one end and wider at the other. The tread depth for the narrow end should not be less than 10 inches, and riser height should be around 7.5 to 7.75 inches. However, there are several other aspects to take care of in these designs — for instance, the overall diameter and the opening size.
How much space do you need for a staircase?
To build a proper staircase, you need space around 3 feet wide and 10 feet long on the floor.
Is a 45 degrees slope safe for stairs?
While not uncommon, 45 degrees slope is quite steep and risky for stairs. Ideally, the slope should not be more than 30 degrees. Lack of space might push you towards a more vertical angle.
Where do you put stairs?
Ideally, staircases must be planned at a spot where they are most functional. However, you need to make sure that the area has enough horizontal and vertical room to build a safe and convenient staircase.
How much headroom should I leave for stairways?
You should have around 6.8 feet of headroom clearance for your stairways. Enough room for an average person and also makes it easier to carry furniture through the stairs.
Are angled or spiral stairs safe?
Angles and spiral stairs serve an aesthetic purpose. They aren’t the best option as far as safety and functionality are concerned.
Now that you know how important it is to follow the best practices when it comes to stair dimensions make sure you are picking the right spot in the first place. With enough horizontal and vertical space, it is easier to follow the codes and built better safer stairs. Remember, staircase safety is extremely important for homes with kids, pets, the elderly, or anyone with mobility issues.