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  • Writer's pictureJosh Lefebvre

How To Calculate Double Winder Stairs

There are several ways to calculate winder stairs, I'll cover the easiest method i'vet found, which uses the RedX Stairs app

The images below are an example of what we the app will generate.

Measurements Required:

Here is the information you will need to enter into the app.

  • Stair total rise

  • Stair case total run

  • Winder Post width

Next select how the stair will connect at the top.

Stringer top connection redx stairs

Stair Plan:

With the required measurements entered the app will then automatically generate

  1. Top down view

  2. All winder treads with measurements

  3. Top and bottom stringer layout and measurements

  4. Winder stringer measurements

Stair Customization

There are many things we can do to customize the stair plan to make it work for any type of stair

Number of Steps

You set how many steps (risers) the Upper Stringer, Lower Stringer and Winder will have.

Stringer Details

  • Stringer Width

  • Stringer Thickness

Tread Details

  • Tread Thickness

  • Riser Thickness

  • Nosing Width

stringer thread thickness stair riser thickness stair nosing width

View measurements

Now you can have a look at the Top and Bottom stringer layout and all of the winder tread plans

Save And Load Jobs

Now that you are done creating your plan lets go over how we can Save and load stair plans to the app for later use.

Saving a Job

Tap on the Save this Job button just above the plan, then tap on Name This Job to add a name. After that tap on the Save button!

Loading a Job

Tap on the Load A Job button just above the plan, then select the job you want to open and then tap on Load.

Print and Share The Plan


Tap on the Print button just above the plan, then select the printer you would like to print to.

Export as PDF

Tap on the Share button just above the plan. This will create a PDF version of the plan that you can share with other apps. For example you can save the PDF to your phone, email it, or send it in a text.

Save To Photos

Tap on the Save To Photos button just above the plan. The app will ask you permission to save the plan to your photos, tap on accept and thats it! The plan will have been saved to your photos.


Now that we went over the basics on how to create and calculate Straight stair plans on the RedX Stair app, you now have a powerful tool to help you calculate and design straight stairs. There are lots of other great features like Straight Stairs, Spiral Stairs, Corner Stairs, Stairs with a Landing and others...

Do you think this is something that you would use? Let me know in the comments.

Thank you to all of you who have made it this far!


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