This image shows an early design intent drawing of a Junior Tower; that is a 12' by 12' tower suitable for use as a cabin, office space. or spare bedroom.

Junior Towers

Figure 2: This 3D model of a Junior Tower shows the first LookoutTower.Org design to be completely engineered. The design was created by Fire Tower Engineered Timber ( 

Junior Towers

We decided to start small and progressively build larger towers, so our first project has been to design and build a Junior Tower; that is, a lookout tower with a 12' by 12' cabin supported by an 11' foot open base. Figures 2 and 3 show images snapped from a 3D model of a Junior Tower. 

A Junior Tower can be built nearly anywhere: it's foundation requires just four concrete piers, and they can be made by either pouring monolithic large blocks of concrete, or by stacking CMUs (concrete masonry units) and then dumping concrete inside. Because the total height of the tower is less than 25 feet, most residential zoning laws would allow a Junior Tower to be built in a backyard, perhaps to serve as an office or spare bedroom.  

If you would like to build your own Junior Tower -- go right ahead and do it. All these design work has been done, and the relevant files are all in the public domain. (Technically, they are covered by a Creative Commons license, and that is explained below.)

This link leads to the .RVT file used to create the images in Figures 2 and 3. An . RVT file is a Revit Project file used by Autodesk's Revit BIM (Building Information Modeling) program. Inside an RVT file is all the architectural details related to the design, such as a 3D model, elevation details, floor plans, and project settings.

Figure 3: The view from below of a Junior Tower. 

JuniorTower-estamped 5dec21.pdf

Figure 4: This window leads to an open source PDF file with detailed specifications for building a Junior Tower. The design was sealed by Ben Brungraber, Ph.D., P.E.. Ben co-founded Fire Tower Engineered Timber ( and is a timber frame visionary with more than forty years of experience in the field, including trend-setting research on mortise and tenon joinery.


About Sandbox Towers

Our first project was to define a new class of buildings called Sandbox Towers. This effort was completed in January 2020. This entirely theoretical design process created a set of design goals explaining how we expected Sandbox Towers to be  designed and built. The Junior Tower describe above is the first instance of a Sandbox Tower that has been completely designed and engineered.

As the five-page PDF file nearby explains, we expected a Sandbox Tower to use wood columns supporting a rectangular structure with balloon framing. Like shipping containers, we expected Sandbox Towers to be quite flexible, so they could be Apartment Towers, Office Towers, Shopping Towers or multistory homes. We expected Sandbox Towers share these common features to make them easy to design, engineer, and construct: 

Figure 5: This logo comes from the Creative Commons website available at

Figure 6: Please use this Creative Commons attribution if you reprint or otherwise use the Junior Tower designs shown in Figures 2, 3 or 4.

Creative Commons License

The work shown in Figures 2, 3 and 4 was initially created by Dave Sullivan working closely with Fire Tower Engineered Timber ( and is licensed under a Creative Commons Attribution 4.0 International License. We chose this license to promote the open source development of lookout towers while giving credit to people who contribute design and engineering work to LookoutTowers.Org. 

If you look up this license on the web, you will find you are free to:

As long as you agree to the follow these simple terms: