Modular buildings, which are constructed offsite in segments before being assembled onsite, are gaining popularity as an affordable and sustainable solution for private homes, but are gaining some popularity in larger projects, too. CitizenM has been stacking up its pre-built rooms to create hotels around the world, including in New York—and most recently a hotel in Seattle’s South Lake Union designed by architecture firm Gensler.

CitizenM’s rooms were built offsite at Polcom Moduling in Poland, complete with flooring fixtures, and furniture—”everything except the mattress, pillow, and towels,” said CitizenM in a press release. Every piece of the hotel was shipped from Europe on the Thorco Legacy, unloading at the Port of Everett this past August.

This week, general contractor Mortenson started stacking up the rooms at the construction site at Westlake and John, where building elements like staircases, utility hookups, structural decks, and hallways have already been constructed. Now, it’s just a matter of assembly.

The small hotel rooms arrived in Everett already complete with built-in bed platforms, showers, and decor already at the ready, which gives us an early peek at the hyper-efficient units—although photos currently show the picture windows peering out into a warehouse as opposed to the street.

According to Mortenson, using this method reduces construction costs, limits pedestrian and traffic interruptions around the construction site, and reduces construction waste by 60 percent.

Seattle’s CitizenM is scheduled to open in 2019.