Esther Collins sat on the front steps of her brick home in north St. Louis on Saturday afternoon, and watched as hundreds of volunteers scurried around her block with ladders, paintbrushes and drills.

"It's just wonderful," said Collins, 72. "I'm just so happy to see them here."

Collins has lived on the 4400 block of Clarence Avenue since 1963 and watched in recent decades as the neighborhood began to crumble.

But for about 12 hours Saturday, the sound of decay was overwhelmed by the buzz of power saws, as seven of Collins' neighbors had their homes rehabbed.

The idea, from Alderman Antonio French, D-21st Ward, is that if the city — with its corporate and nonprofit partners — can leverage volunteer muscle to refurbish multiple homes on one block for one day each month, an entire section of the city can be saved one block at a time.

"I don't know if the idea is original, so much as it is common-sensical," French said as he watched volunteers reconstruct a front porch. "It might sound strange, but it's a more efficient use of tax dollars to rebuild a community block by block."

French said that when he was elected last year, his office had about $70,000 at its disposal for residential renovation. The money was helping about seven homeowners a year. But there were more than 450 applications, and helping one resident here and another on the other side of the ward didn't seem an efficient way to aid the community.

The alderman approached David Ervin, executive director of Rebuilding Together St. Louis. French knew about the group's annual Rebuilding Day when volunteers rehab 100 homes in St. Louis and St. Louis County in one day.

He asked Ervin to help organize rebuilding days focused on one block of the 21st Ward each month for six months.

"Doing block-by-block is somewhat easier than being spread out over the area," Ervin said. "All the supplies are on one street, and there's a concentration of forces. We'll probably do more things like this in the future."

Rebuilding Together St. Louis has been working since 1994 and had done rebuilding projects with Boeing. Boeing's volunteer program was growing rapidly, and the company was looking for more outlets.

Eliza Thompson, Boeing's Rebuilding Day program manager — whose weekday title is F-15 Korea System Engineer — said the company's volunteer pool had grown from about 200 in 2005 to 1,500 today.

French's office took six months to plan the monthly Rebuilding Days, and launched its first effort, with Boeing and Rebuilding Together, in May, repairing 10 houses in the 4400 block of Penrose Avenue.

In June, volunteers tackled 15 houses in the 4000-4100 block of Taylor Avenue. In August they move to the 2000-2100 block of Fair Avenue.

The ward has 186 blocks, and French's office picks which block to rehab by studying applications and mapping the needs into clusters. Home ownership and financial need determine which houses are visited by the volunteers. The city spends money on infrastructure — fixing sidewalks, alley access, streetlights — on the blocks French's office chooses for renewal.

French says that by year's end, thousands of volunteers will have rehabbed 70 houses for about $300,000. French's project spends an average of $7,000 on each house.

Justin Rathert, 27, a program manager for Boeing's IT department, was the "house captain" for 4407 Clarence.

He directed 30 volunteers, who ranged from entry-level Boeing employees to vice presidents, with what Rathert diplomatically called "varying skill levels" of construction experience.

His team was tuckpointing, hanging doors, running electrical wiring, painting, plastering and pouring new concrete steps.

Across the street, Betty Newburn, a homeowner in her 70s who has lived on Clarence for 41 years, watched as another team put a new deck on the back of her house, ripped up carpet and laid new hardwood flooring, replaced her kitchen cabinets, replumbed her bathroom sink and built new front steps.

"It's amazing to watch," Newburn said. "I've never seen anything like it in my life. It's a blessing to me."

Next door, Terry Beck, 49, and Arthur Mayfield, 46, both of whom grew up in the neighborhood, sat on the stoop and watched the activity.

"In this economy a lot of people with fixed income, a lot of older people, could never afford this," Mayfield said.

"It's a great thing to help people who can't help themselves," Beck said.