In murky April weather, crews sent 8 inches of rain over 15 minutes gushing down on samples of an internal membrane planned to stop the Air Force Academy chapel from leaking.

At the same time, an airplane engine mimicked the high winds that can down trees in Colorado Springs.

Crews ran the test outside the big, white box that has hidden the chapel for years during extensive restoration that started in 2019.

The building, modeled after famous European cathedrals, such as Chartres and Notre Dame, is still a skeleton of tetrahedrons, awaiting its new membrane system and aluminum skin.

The new membrane system is critical because the chapel was plagued with leaks immediately after it opened in the 1960s, Academy Architect Duane Boyle said. To save costs, the original membrane system was removed from the designs and replaced by 32 miles of caulking.

To try to stop the leaking, stop-gap measures went in, such as storm windows that blocked about 50% of the light coming through the stained glass.

“When the building opens back up, it’s actually going to be brighter,” said Marty Rickett, a senior project manager for JE Dunn, the general contractor.

The building is slated to open in 2027 after eight years of highly detailed restoration expected to cost $250 million. The building was originally built for $3.54 million.

While it would have been less expensive to rebuild preservation is the focus because of the building’s status as a National Historic Landmark, Rickett and Boyle said.

The high costs have been driven by the complex design of the building.

“There is nothing common about this building,” Boyle said.

It’s also the site of the largest asbestos abatement in the state, he said. The removal filled 147 dumpsters and cost $62 million, the Gazette reported previously.

Since crews removed the final exterior panel on the building last spring, workers have laser scanned the building to create a computerized model of it and found the pipes slightly off — up to five-eighths of an inch, Rickett said.

So teams are working to adjust individual panels to ensure they fit perfectly, he said.

The building and its new internal membrane will be tested again to confirm that it’s water tight.

When the general contractor took over the building the leak situation was so bad that melting snow made it look like it was raining inside.

When the outer structure is complete, crews will install the refurbished pipe organs and the pews, while the big white box comes down, Rickett said.

“It will look exactly the same, except brand new,” he said.

While work is ongoing, the 450 to 500 cadets who attend weekly religious services gather at other sites on campus, Chaplain Capt. Jennifer Ray said. The academy serves Protestants, Catholics, Jews, Muslims and Hindus.

“We are looking forward to this place being resurrected,” she said.