You might have seen her at the corner of Maple and Philadelphia avenues, blocking traffic so children can cross the street safely.

Minnie C. Johnson, 69, has dedicated her life to helping other people, first as an electrocardiogram technician at Holy Cross Hospital and now as a crossing guard in Takoma Park.

When she needed assistance keeping up with household repairs she could not afford, Rebuilding Together Montgomery County was there for her.

“Let’s just say, I was blessed all the way around,” she said. “Paying the mortgage and paying bills, there’s not too much left over to do anything.”

Last April, Rebuilding Together volunteers put grips in the bathtub of her Silver Spring home, carpeted the bedrooms and the stairwell, fixed an outside railing, laid flooring in the kitchen, and put in a new refrigerator and dishwasher. They also installed central heat and air conditioning — her first time living with that luxury.

Rebuilding Together Montgomery County is trying a new project, Rebuilding Hope: The RTMC Playhouse Project. Eight builders are crafting playhouses that will go to auction May 31.

Organizers hope to raise more than $100,000 to benefit people such as Johnson, said Susan Hawfield, executive director of Rebuilding Together, a nonprofit group dedicated to helping low-income homeowners fix deteriorating houses. Repairs range from minor problems to major structural modifications. Its budget is funded by the county, state, donations and grants.

Volunteers work on about 120 houses in Montgomery County each year. The organization rarely advertises because word of mouth is enough to keep them busy, Hawfield said. Rebuilding Together has 100 people on its waiting list.

The playhouse fundraiser was made possible by Montgomery County’s construction industry, which still is reeling from the recession.

“Hardly anybody got hit worse in this area than contractors and material supply, and yet the contractors are the ones that are putting in all this good time for the community,” said Jerry Liu, president of D.G. Liu Contractor in Dickerson. “The material suppliers are backing us up.”

Most of D.G. Liu’s 12 employees are working on the company’s Asian-themed playhouse, a teahouse with exposed posts and redwood rafters that retails for $10,000.

The company has been working with Rebuilding Together for 22 years. As construction chairman on Rebuilding Together’s playhouse committee, Liu reaches out to builders.

Each playhouse is built on an 8-by-10-foot platform, but heights vary, he said. Bidders will have a chance to own Liu’s Playhouse of the August Moon, medieval fortress, mini-mansion, lighthouse, cottage, firetruck or two-tiered discovery pod that includes a window seat, insect viewing boxes and space for a koi pond or sandbox.

Organizers seek to raise $15,000 to donate the Walter Reed General Store to the Walter Reed National Military Medical Center. The playhouse is open at the back, which will allow parents in wheelchairs to enter, said Karen Smith, a Rebuilding Together board member who pushed for the fundraiser.

The fair-market value of the playhouses ranges from $6,500 to $15,000, according to the Rebuilding Hope Web site. Any bid amount above fair-market value is tax-deductible.

The brainchild of Anthony Wilder Design/Build in Cabin John, the firetruck is a community effort.

Individuals and teams from the company vied for the best concept, but the winning design was chosen by the company’s clients. After nearly 100 votes, the firetruck was the winner. The truck features tire slides, tunnels and solar lights.

“It’s almost around the clock, because everyone is thinking about it — what kind of details can we put into it to make it as detailed and realistic as possible?” said Anthony Wilder, principal of Anthony Wilder Design. “People come up with it on the weekends, in their sleep.”

They have gotten more from the experience than they are giving, said Sean Mullin, an architect with Anthony Wilder , who designed the firetruck.

“Not only are we getting to have fun building it and designing it, but it’s all for a good cause,” he said. “Bottom line is, we’re helping Rebuilding Together.”