Elon Must announced last month that he planned to create bricks out of dirt to build low-income housing, reports Bloomberg's Sarah McBride. But critics are wary that his plan will actually alleviate the housing crisis.

How many affordable housing units those bricks will create, though, is a different matter, says Juan Matute, a lecturer at the University of California, Los Angeles, and associate director of UCLA's Institute of Transportation Studies. Musk’s tweet "assumes that housing costs are driven by construction materials, and particularly, construction materials that can be replaced by bricks," Matutue said. "That's not the case." At least in California, the only state where Boring Co. has started digging a tunnel, land and labor drive prices more than anything else.

Going forward, a spokesman said, the company plans to make bricks out of excavated mud from all Boring Co. tunnels, not just the one currently under construction in Hawthorne, California, on land owned by Musk's Space Exploration Technologies Corp. When it comes to actual housing construction, bricks tend to be expensive, in part because assembling brick walls takes more work than other options, such as putting up panels. And because bricks don’t stand up well to earthquakes, a major concern in fault-riddled California, building codes typically require buttresses such as reinforced steel and rebar when bricks are used.

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