3D stair calculator project walk through

Designing and manufacturing a staircase can be one of the trickiest tasks in woodwork. However, if you use a 3D stair calculator you can speed up the process massively and at the same time eliminate errors.

It’s much easier to use a staircase calculator than drawing by hand, or indeed drawing using a CAD package. Instead you input the project dimensions, add components and adjust their parameters. The software does the hard work and calculates a safe, good looking and easy to build stair for you.

In this example, we’re going to create a quarter turn right stair using StairDesigner, a professional stair calculator.

Step by Step Summary

Step 1: Take the stairwell dimensions
Step 2: Initial quarter turn staircase calculator set up
Step 3: Optimise for safety
Step 4: Headroom control
Step 5: Optimise for aesthetics and ease of manufacture
Step 6: Output your stair cut list and plans
Step 7: Expand your design options

Step 1: Take the stairwell dimensions

Without a doubt the most important step of all. Take time to get the stairwell dimensions right, you’ll save much more time in the long run if you do.

Despite your best efforts, 100% accuracy is practically impossible however. For this reason it is a good idea to introduce a minimum play. It’s much easier to add fillers to make a slightly too small stair fit, than to cut down a stair that is too large. Allow for 10 mm play between two walls, or 20 mm if the walls are particularly irregular.

The basic set of measurements you’ll need are shown below, we’ve added in some example dimensions to use:

• The height from floor to floor: 2800 mm
• The length and width of the stairwell which will give the length of each flight in StairDesigner: for example 2000 mm for the 1st flight and 2500 mm for the 2nd flight
• The width of each flight: both 800 mm
• Thickness of the floor joist will also be needed to calculate headroom

And remember to always use the same units of measurement. Don’t change between metres, centimetres and millimetres, or between feet and inches. It is much easier to misinterpret your recorded dimensions if you do.

Step 2: Initial quarter turn stair calculator set up

Open up the StairDesigner stairs calculator and create a new stair from the model catalogue. Select Model #2 from the ‘Stair without Landing’ list. This is a classic quarter turn to the right stair.

Now enter your overall stair dimensions.

• The overall stair height of 2800 mm, this is the first parameter to enter.
• We’ve got two flights in our quarter turn stair, now we enter those dimensions.
• A good stair width is 800 mm so let’s go with that for both flights as we’ve said above.
• A stair should normally have a landing step as well, let’s include one and set it’s width at 100 mm.

At this stage we can also very quickly set up some other key assembly details:

• Stringboards: let’s have strings on both side of the stair, to the left and the right
• Handrails: just on the right this time as the other side of the stair is against the wall
• Lateral cut strings: these are strings that are cut so the steps sit on the string rather than being housed within them – we’re not using this construction method here so we’ll say no in this case
• Newel posts: to go with the handrails, we’ll chose to have them on the right side only

Click OK and we’ve got our basic design already created in StairDesigner. The image below is taken from StairDesigner and shows the stair in plan view and also in 3D.

Step 3: Optimise for safety

The overall properties of the stair are shown in the Properties menu.

The number of steps is shown by the number of risers. The optimal number of steps/risers is automatically calculated by StairDesigner.

From that number, and knowing already the total height of the stair, the riser height is calculated and shown in the properties as well, along with the tread width (also called the going).

The tread width is the distance from one step nosing to the next along the treadline.

Finally in this section of the Properties menu stair is the Stair Rule calculation.

This value is 2 x RISER HEIGHT + 1 x TREAD WIDTH

There are control values for all 3 of those, shown below.

You should set the range of values to promote a safe stair. You don’t want the height of the riser to be too big. You also want a sufficient tread width so there’s enough room for your foot to fall on.

If the control window indicators are not being met, you can always change the quantity of risers/steps and also the length of the flight if the room allows it in regards to the headroom space, more on this below. This will automatically recalculate all values so that you can have a stair that meets requirements.

In practice, it will not always be possible to get all the values within the given range but then you can make sure they are as close as possible to the window value or even get 1 parameter within the value. This is a compromise you make and it will always be determined by the situation.

Step 4: Headroom control

StairDesigner includes the option to draw the stairwell on top of your stair design in order to calculate the headroom.

You can edit the shape to represent the real stairwell on site. StairDesigner will then, based on the start of the well hole, the floor thickness and its position in relation to the steps calculate the headroom space. If it falls outside the control window requirements it would be shown in red.

The headroom minimum height can be set in the control values. The tolerance is the percentage of the step width which is excluded in the headroom calculation, starting with the sides of the step and so the part of the step you are less likely to be using. In this case the first 5% of the step width is not taken into account for the calculation of the headroom space.

Step 5: Optimise for aesthetics and ease of manufacture

Steps first

In the stair shown above all steps are gradually tapered in and out of the turn, this is the safest way to build a stair.

For aesthetic or technical reasons, the winding of the steps may need to be adjusted. StairDesigner has a number of winder stair calculator features built in for this.

This can be done globally by using the sliders local and distant. This ensures that the winding is adjusted for all steps together. The higher the slider value, the straighter the steps become. With both sliders at maximum value, you get a maximum number of straight steps.

In some countries it is common to have the tapered steps, also called winders, just around the turn. Another way to do this efficiently is to set the start and end winders in StairDesigner by applying fixed steps (marked in red), the result is shown below:

The reason you’d build a staircase like this? Well, it’s much easier to manufacture, most steps are identical and simple.

Finally, you can modify steps individually. Select a step, right click and convert to a floating step, indicated by an orange colour this time. You can now modify this step, drag it into a new position for example, without affecting the other steps.

Stringboards

StairDesigner will automatically calculate the shape of the stringboards taking the steps into account. If you prefer to adjust them, you can easily change them to a straight type and adjust the necessary angle parameter for this.

You can also change the shape of the stringboard completely to your liking via the editor for aesthetic reasons, adding curves for example. The ease of use of this particular adjustment feature makes StairDesigner unique amongst stair calculators.

Handrails, newel posts, and more

In fact, you can adjust all the components of your stair to create your preferred combination of a good looking design that is as easy as possible to build. For example, we can fine tune the look and position of the handrail and newel posts, for now let’s just take a look at the step and riser parameters.

Some of the step properties are shown in the image below.

You can see that it’s possible to adjust the material, in fact you can adjust the material of each individual step if you want. You can also adjust step thickness, how wide the nosing is and the exact assembly of riser to steps.

Step 6: Output your stair cut list and plans

Once you’re happy with your stair, output of the manufacturing files is virtually instant. You can print a workshop document containing the cutting list and plans of each part, you can create 1:1 templates, and you can export each part as a DXF or in a range of other file formats for a CNC machine.

Diagrams of the full stair and elevations are also readily available.

Step 7: Expand your design options

It’s very easy to move beyond simple L shape stair calculator operations. Here we’ll show you how to add a landing to your project, and create U shaped stairs.

Stairs with landing calculator

StairDesigner allows the insertion of landings of different shapes, each with its specific parameter set.

Options include:

• Joining two straight flights running in the same direction
• A landing as part a quarter turn stair to the right or left
• Joining two flights at an irregular angle
• A landing turn as part of a U shaped / half turn stair

As well as inserting the landing between two flights, they can be inserted at the staircase’s beginning and end.

U shaped stairs calculator extension

StairDesigner goes further and allows you to add flights and landings of your choice. In this example, we’re inserting an intermediate landing, then an additional flight, which now makes it a U shaped stair.

A U shaped staircase can also be created directly via the existing models or the multi-flight application.

StairDesigner pro and amateur options

Professional use

There is the option to buy StairDesigner outright to have immediate access to all this output for your own projects.

One-off and occasional use

Alternatively and for those working on only the occasional stair project, there’s the option to use the free version of the StairDesigner 3D stair calculator. This version allows you to design in full, but it doesn’t give you the output such as the cut list, plans of each part and 3D and elevation diagrams.

To get that, sign up for a Premium Support subscription and use our stair cut list and plan processing service.

Get started today

Please click here to download StairDesigner.