NORWAY — Contractors are putting the finishing touches on a home they’ve built for free for the family of a 10-year-old boy recovering from third-degree burns over 70 percent of his body.

“Everyone has been so wonderful,” said Susan Duchaine, the builder who organized the volunteer effort.

The house, a four-bedroom split foyer, now stands on a wooded lot owned by the mother of burn victim Andrew Frechette outside of Norway. The exterior is finished, and workers are installing insulation, wiring and plumbing.

“The (contractors) I know, it doesn’t surprise me, but I couldn’t believe how many people wanted to be involved and how generous everyone has been,” said Duchaine, owner of Design Dwellings in Gorham. “It’s unbelievable.”

More than 50 contractors from Limerick to Naples to Belfast joined together to build the home, valued at $70,000, for free for Andrew’s family.

The contractors’ gift tops a list of donations the family has received from people touched by the story of Andrew, a sensitive, good-natured boy who won a battle with leukemia and then was burned by an exploding gasoline tank on Dec. 9.

Andrew is undergoing painful skin-grafting in a Boston hospital. He is expected to return home sometime in the spring, his mother said.

On Wednesday, Janet Frechette, Andrew’s mother, left her son’s side and returned to Norway by bus to visit her three daughters. She also went to see the new house.

“I cried because it’s still unreal,” said Frechette, who had lived in a run-down mobile home with no running water or sewer. “I’m thankful, more than I could tell anybody. But I have mixed feelings.”

Frechette said her thoughts about receiving a new home may differ from those who donated it.

“It seems like, you know, we benefit because of this accident,” she said. “But if I could change it, if I could go back to Dec. 9 and change it, I would live in a tarpaper shack.”

Frechette said the new house excites her son, who remains immobilized with his body covered in gauze, and gives him an incentive to keep fighting.

Andrew is in stable condition. His bout with leukemia has made his skin thin, doctors say, which is keeping areas of his body used for grafting skin — the back of his legs and buttocks — from healing as fast for more grafting.

The grafting on his arms was not successful and will need to be repeated, his mother said. Since the accident, the boy’s left lung has collapsed twice, and he contracted a mild case of pneumonia, she said.

Frechette now can feed her son, but must use her fingers. He recently had his favorite food, pork chops.

Frechette said Andrew will not talk to her about his pain.

“He’s very compassionate for me. He doesn’t want to hurt me,” she said. “He’s told me two or three times he’s sorry. Finally I said, `What are you sorry for?’ He said `I’m sorry for putting you through this.’ This is coming from a 10-year-old boy.”

Once Andrew is released from the hospital, he will require constant supervision and also need to be bathed and have his bandages changed four times a day.

Donations for the family’s expenses have reached $20,000, said the United Way’s Kathleen Scott, fund-raising adviser for the Andrew Frechette Committee.