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Imagine entering a massive, centuries-old fort on a secluded island, armed only with flashlights and state-of-the-art laser scanners.

This was the unique challenge faced by Existing Conditions as we embarked on documenting the intricate and historic Fort Warren, showcasing how modern technology can breathe new life into our treasured past. Read on to learn how we documented this historic marvel.

History of Fort Warren

Interior of Fort Warren

Interior of Fort Warren, George's Island (courtesy of the Boston Public Library).

Fort Warren is located on George's Island in Boston Harbor. It began being built in 1833 and was mostly finished by 1861, taking nearly 30 years to build. Throughout its construction period, the fort kept updating based on new military technologies and continued to see changes up until World War II, during which an observation tower was added.


1842 planned sections (courtesy of McGinley, Kalsow, & Associates).

The fort has over 110 years of construction. It was initially designed as part of a defense system created after the War of 1812 to protect the East Coast from foreign threats, mainly from England. Fort Warren played a significant role during the Civil War and served as a control center for mining operations in Boston Harbor during World Wars I and II. It even had a special tower to watch for German submarines. The fort is shaped like a pentagon but not a regular one—it was built this way to fit the natural layout of the island, making it a large and unique structure.

Learn more about the history of Fort Warren on Georges Island by watching this YouTube video by the Boston Harbor Islands.


Partnering with McGinley, Kalsow, and Associates

Existing Conditions has a longstanding partnership with Wendall Kalsow, Principal, and President at McGinley, Kaslow, and Associates, collaborating on numerous high-profile historical projects over the years. The Fort Warren on Georges Island project was a continuation of this established relationship, building on the strong foundation we've developed with Wendell Calso through past collaborations.


For this project, given the substantial size of Fort Warren, hand-measuring the existing building drawings would have been a nearly impossible task. Especially considering elements like non-perpendicular walls and arches, obtaining accurate measurements would have been highly challenging. McGinley Kalsow & Associates, Inc. selected Existing Conditions to deliver reliable Revit files and detailed as-built drawings of the entire fort.

Fort Warren on Georges Island Map

Fort Warren on Georges Island map (courtesy of McGinley, Kaslow, & Associates).


Scope of Work Evolution at Fort Warren

The scope of the project at Fort Warren remained relatively consistent from start to finish, focusing mainly on utilizing the FARO Focus 3D S50 laser scanner to capture the entire fort with great detail. Our team, which included six people, worked on getting detailed scans of the fort’s floor plans, reflected ceiling plans, and exterior elevations, particularly around the main entrances. Throughout the project, there weren’t any big changes or additions to what we planned to do. We stayed focused on creating detailed documents of the fort’s complex design.

Exterior Photo Fort Warren

The exterior of Fort Warren was pictured while scanning on-site.

Fort Warren isn’t built like modern buildings. Its design doesn’t follow straight lines and often includes uneven shapes and surfaces. This made it a tricky place to work because our team needed to use very careful and flexible scanning techniques to get all the details correct. Existing Conditions had to make sure every part of the structure was captured accurately.


Over three days, Existing Conditions scanned the fort. Once on-site, Existing Conditions moved through various parts of the fort, some of which were hard to get into. Areas with spiral staircases or potential safety risks needed careful planning to make sure the team could work safely and cover all areas thoroughly. In addition, the building's earth-covered roof presented challenges for 3D laser scanning, but we managed to conduct 85 scans to capture the vast site.

Sketch to Plan Scanning

Sketch by Existing Conditions to help plan out the scanning.

Safety hazard of fallen bricks at Fort Warren

Fort Warren safety hazard pictured while scanning on site.

Working closely with McGinley, Kalsow, and Associates was important. Existing Conditions ensured the digital models of the fort met the needs for fixing and maintaining it in the future. It was thanks to this teamwork that the project progressed smoothly. The project was completed in August of 2018.


The Challenge

Ferry Boat to Fort Warren

Ferry commute to Georges Island on June 5th, 2018.

Reaching Fort Warren during the off-season presented significant logistical challenges due to the absence of regular ferry services. To undertake any preservation or improvement project, special arrangements had to be made to transport both the crew and equipment to the island. Even simple visits required detailed organization to coordinate the limited transport options available, turning what would usually be routine trips into complex excursions.


This transportation issue was compounded by the fact that any work needed to be completed within a short timeframe. The lack of regular access meant that each visit had to be highly efficient, with all necessary materials and plans ready to go. This included extra batteries for the scanners, lunch, water, and more since there were not any amenities on the island. Every trip was critical, and any delay or oversight in preparation could significantly set back the project, adding time and cost.

Moreover, the unpredictable weather and sea conditions during the off-season added another layer of complexity to these arrangements. Planning had to account not only for logistical and timing challenges but also for the safety of everyone involved. This often meant waiting for the right weather window to carry out the transport safely, further narrowing the work opportunity.


The Solution

Point Cloud Data Floor Plan

3D laser scan data of a floor plan of Fort Warren.

The deployment of 3D laser scanning technology was a game-changer for documenting and analyzing the complex structure of Fort Warren. Existing Conditions was able to capture detailed measurements of the fort’s irregular and expansive layout quickly and accurately. Traditional methods, such as manual measurement, would have been impractical and error-prone given the fort's complicated architecture and scale.

The data captured from laser scanning was then converted into Revit files, creating a building information model of the fort. These files are incredibly detailed, offering a three-dimensional view that highlights every architectural nuance, which is crucial for planning restoration

accurately. This digital representation is invaluable not just for current restoration efforts but for future preservation activities as well, allowing conservators to pinpoint areas in need of repair without intrusive physical inspections.


3D Revit Model

3D Revit model of Fort Warren.

Looking ahead, the digital tools and files generated from the laser scanning project are expected to guide the restoration and maintenance of Fort Warren for the next 20 years. The Massachusetts Department of Conservation and Recreation, which now holds these digital assets, can plan and execute restoration projects more effectively. These projects not only aim to stabilize and restore the fort but also enhance its accessibility and educational value for visitors, ensuring that this historical site can be enjoyed by future generations.

Floor Plan

Floor plan of Fort Warren.


How This Project at Fort Warren Was Unique

Georges Island Dock

Georges Island Dock.

The Fort Warren project had some special challenges because it was on an island. To get there, the team worked with the National Park Service and used a special boat from the Parks Department. This boat was quicker and went straight to Fort Warren, unlike the public ferry that stopped at many islands and would have taken much longer.

Working at Fort Warren felt like stepping back in time because the old fort doesn’t have modern things like electricity. The team used advanced scanners to get detailed documentation of the fort, but in some darker, enclosed spaces, they even needed to use flashlights. This made the job a bit like a historical adventure.



Depth_thickness of Fort Warren Walls

This image depicts the depth/thickness of a wall. Necessary construction was needed for the safety of weapon storage rooms.

It was also really important for the team to keep track of time. Existing Conditions had to catch the boat on time in the morning. If we missed it, they would have to wait for the slower public ferry or might even get stuck on the island until the next boat. This made planning very important and added an extra challenge to our work.


About the Client McGinley, Kalsow, and Associates

McGinley, Kalsow & Associates is an architectural firm that has been dedicated to the preservation of historical sites, primarily those listed on the National Register and recognized as National Landmarks, across New England for the past 40 years. They have undertaken several projects on George's Island, including the restoration of the mine storage building, the generator building, and the training center.

Wendall Kalsow is the Principal and President, and the firm is known for working on old and important buildings. He's an expert in assessing, restoring, and adaptively reusing historic buildings that are often recognized as National Historic Landmarks. Wendall possesses a deep knowledge of how old buildings were built and the best ways to fix them. He's committed to making sure that modern features like accessibility and updated building systems are added to old buildings without losing their historical charm.

Wendall also helps out on the board of Preservation Massachusetts and is part of the Lexington Historical Commission. For his outstanding work in preserving historical sites in Massachusetts, he received the Paul E. Tsongas Preservation Award.


Wendall Kalsow (Photo courtesy of McGinley, Kalsow, & Associates).

“The scale of Fort Warren, its irregular geometry, and the structural changes it has undergone over more than a century, presents unique challenges. Given its complexity and from my experience dating back to when we manually measured buildings, using traditional methods here would have been virtually impossible. The use of laser scanning and the creation of Revit files for this project provided extremely accurate information about this irregular geometry, which is a significant advancement. The Department of Conservation and Recreation now holds these files, and they will be instrumental as they secure funding for various restoration and stabilization projects over the next 20 years” - Wendall Kalsow, Principal and President at McGinley, Kalsow, & Associates.

Join us in preserving history with cutting-edge technology.

Contact Existing Conditions today to ensure your historical site is accurately documented and maintained for future generations.


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