Indoor building material-maker Serious Materials has taken on a large $50 million second round of financing to launch a line of environmentally friendly drywall, the most common indoor building material in the United States.

Indoor building material-maker Serious Materials has taken on a large $50 million second round of financing to launch a line of environmentally friendly drywall, the most common indoor building material in the United States.

The funding will help the company cover the costs of a manufacturing plant, to open next year. The cost for new plants commonly runs into tens of millions of dollars.

Serious will make three product lines: EcoRock, ThermaProof, and Quiet Solution. EcoRock is drywall that produces less carbon dioxide and harmful chemicals to make, ThermaProof provides superior insulation against temperature extremes, and Quiet is a line of soundproof building materials.

We reported on Quiet earlier this year, without mentioning that Serious is the parent company's name. Marc Porat, a successful Silicon Valley entrepreneur, started it along with a pair of other green building companies, California Cement and Global Homes, which remain secretive.

Porat's persistent investments into green building suggests he foresees a lucrative market. He isn't the only one. Khosla Ventures, which invested in California Cement, also recently put money into Calera, which has plans to recycle escaping carbon dioxide into concrete. Gigacrete is another company after the same market.

Other green-building startups range from Solar Cynergy (our coverage ), a decorative LED maker, to the entire gamut of solar cell makers, who rely in part on consumer interest in solar paneling for their homes.

The funding for Serious Materials was led by New Enterprise Associates and Foundation Capital. Rustic Canyon Partners, which provided the previous round of $5 million, also participated.