Department of Building Inspection spokesman William Strawn said inspectors discovered the contractor had not obtained an excavation permit for work being done at the home, located at 38 West Clay St.
A concrete pillar for the home's backyard patio collapsed at about 12:50 p.m., causing a worker in his 30s to fall into a trench. He was buried in sediment that at one point reached his neck.
Fire crews were eventually able to rescue the man at about 4:50 p.m. He was taken to San Francisco General Hospital, where he was found to be in good condition and was released later Tuesday, hospital spokeswoman Rachael Kagan said.
Crews were remodeling the home and rear yard at the time of the accident, including adding a deck to the garage roof and a retaining wall and new exterior stairs in the backyard, according to Strawn.
He said the contractor, Brian MacNamara Construction, had appropriately obtained a building permit in March, but the company exceeded the scope of the permit and did not get the required excavation and shoring permit.
The stop-work order was issued late Tuesday. Crews will not be able to resume work at the site until the necessary permit has been obtained.
A geotechnical expert will also have to do a soils report before work resumes, that individual and must be on site for any future excavation and shoring on the property, Strawn said.
The California Division of Occupational Safety and Health was also at the site today conducting an investigation into the incident, spokeswoman Krisann Chasarik said.
Chasarik said Cal/OSHA also issued an order to stop work at the site Tuesday. Before work starts again, contractors will "have to prove to us that the area's been shored up. We'll go back out there and re-inspect it," she said.
Calls to Brian MacNamara Construction were not returned today.