Since Russia’s invasion, more than 6.5 million internally displaced people in Ukraine have fled their homes to find safety. Many of them are currently crowded in large spaces like school gyms or bomb shelters, with bare amenities available. In a bid to properly accommodate these refugees, a team of architects has designed modular shelters that can be quickly built.

It was Kyiv-based architect Slava Balbek who kicked off the project after contemplating the urgent need for new housing for those who’d had to leave their homes. Together with a team of 10 architects, Balbek came up with a design for a modular refugee shelter that’s both quick and affordable to build.

Thanks to their modular design, the shelters can be arranged in different configurations to house up to hundreds of people. The design also includes green space and room for playgrounds and sports fields. But the best thing about the initiative is that the design is open source, meaning that it’s available to anyone who wants to use it.

The first shelters are expected to be built in Western Ukraine, where many people have fled in the past couple of weeks because it’s relatively safe. Just one day after publishing the design, Balbek’s firm received hundreds of messages from people willing to volunteer or invest in the project. A company in Lithuania, for example, offered to donate building supplies.

“Now we’re trying to manage all over Ukraine,” Balbek tells Fast Company. “We already have two sites in different cities, and they’re already waiting for the drawings,” he says. As new sites become available, architects in Western Ukraine have offered to volunteer to adapt the plans according to those spaces, which doesn’t require a lot of effort because the architecture firm designed the plans so they can be easily adapted for different locations.

Working on the designs has also helped the architects cope with the reality of suddenly having to live in a war zone. “I remember in the first days, we were counting hours,” says Balbek. “You’re looking for the news. And we were just sitting outside at the café, all the volunteers, and we just realized that a month has passed. It’s huge. The helpful thing is to focus on something. For me, that’s this project.”