Prefab building maker Cover Technologies Inc. has assembled a milestone.

The Gardena company, which designs and builds accessory structures including guest homes, offices and artist studios, said this month it completed and installed its first building for a client.

“The first unit was delivered to an Oscar-nominated sound editor,” said Alexis Rivas, co-founder and chief executive of the company, who wouldn’t disclose the buyer’s name. “The client wanted a music studio space, and that’s what we provided.”

Cover and similar companies stand to benefit from a new state law that went into effect Jan. 1 that makes it easier for homeowners to add small in-law units, granny flats and studios to their backyards.

Rivas and Jemuel Joseph founded the company in 2014, but things didn’t kick off until 2016 when they got accepted into Y Combinator, an early stage startup seed funder in Mountain View. At the end of the program, the company announced a $1.6 million seed round in May led by General Catalyst and Khosla Ventures, with participation from Fifty Years, Hyperspeed Ventures and other angel investors, Rivas said.

The seed round helped with hiring, and the company now counts seven employees on its payroll. The staff includes a mix of architects, designers and software and manufacturing engineers.

Rivas said there are more orders on the horizon, and the company expects to deliver around 150 units next year.

Cover’s units start at $55,000 for a basic single-room space that can include plumbing and electricity. They can go up to $500,000, depending on the customer’s customization needs.

It took three months to design and install the company’s first unit, a 320-square-foot studio with a sleek, minimalist design and floor-to-ceiling windows, Rivas said. He wouldn’t say what it cost the client.

Cover doesn’t seem to have direct competitors for backyard homes, although companies such as Pico-Union-based Proto Homes and Blu Homes Inc. in Vallejo build prefab, customizable houses.

“What makes us different, besides specializing in backyard units, is we draw up plans based on the zoning codes for you in as little as three days, when that process normally takes weeks,” Rivas said.

He considers Cover a technology company and said its proprietary software can draw up a floor plan to fit the property and local zoning codes.

“This can be one way in addressing the housing crisis in L.A. without making drastic changes to neighborhoods,” Rivas said.