"It seemed irrelevant to go back to my old job and work for a profit-making company," said Chaggar. So now he manages a housing project for some 180 Thais in the village of Thap Tawan, in the Khao Lak resort area, 360 miles south of Bangkok.
The killer wave that struck on Dec. 26 killed 5,400 people in Thailand, and 2,800 are still missing. Foreign victims numbered 2,436.
Since the disaster, thousands of people from around the world have used vacation time or interrupted careers to help out.
There's Scott Carter of Georgetown, N.C., making fishing boats, and Joa Keis, from Corvallis, Ore., teaching English. Dive enthusiasts are scouring the seabed for debris. Others comb the beaches. The visitors make everything from playgrounds with brightly colored swings to furniture for newly rebuilt homes.
The Tsunami Volunteer Center says it has found work for more than 3,500 volunteers aged 19 to 67 from countries as diverse as Canada, Singapore, Malaysia, South Africa, Saudi Arabia, France, Germany and the United States; 51 countries in all since the center opened in January.
Sombat Boon-ngam-anong, the program's Thai founder, marvels at the sight of Christians, Buddhists and Muslims working together to rebuild homes for Thai victims.
"I see the universality and open-mindedness, which goes beyond religions and races," he says.
"At Thap Tawan, when the volunteers finish building a house, you will see their photographs pinned on the wall. Villagers still talk about this and that volunteer," said Sombat.
He himself fondly remembers a spirited, one-legged woman in her 40s named Elle, helping to rebuild houses.
"When we saw her working, we felt that we couldn't do less than what she did," he says.
At the Phi Phi Dive Camp on the island of Phi Phi, they call it "voluntourism," a program in which some 4,000 volunteers have helped to remove 290 tons of debris from the sea and the beach.
Some stay just a day, others have been here for eight months. Some are here for the first time; others, like Chaggar, were here when the wave struck.
Chaggar and his girlfriend, both from Leicester, England, were on the seventh week of a round-the-world trip when the tsunami pounded their bungalow on the beach at Khao Lak. Chaggar survived with a broken collarbone and badly injured legs. His partner, whom he prefers not to identify, was washed away and her body identified only six months later.
The young engineer returned home and struggled to cope with the absence of someone who had been part of his life for six years. In April he returned, and was recently with six other foreigners mixing concrete under a glaring sun.
The work helped him to get over his loss.
Thousands of fishing boats were destroyed, leaving many villagers without a livelihood. So Scott Carter closed his small engineering firm in North Carolina and moved here in March. He and other volunteers work with fishermen to produce a boat every three weeks, each at a cost of about $3,250. Using donations from Americans and other donors, they have built 36 boats and aim to build 47 in all before turning the enterprise into a commercial one run by Thais.
A self-taught boatmaker, Carter said he doesn't get paid. Payday, he says, is seeing a new boat launched.
"The last boat that I build will be mine," Carter says, a 62-footer which he plans to sail back to the United States next year.
Keis, the 25-year-old from Oregon, has been teaching English to schoolchildren for most of the year to prepare them for jobs in a revived tourism industry. He and 12 others teach 16 hours a week.
He says he was amazed by the resilience and optimism of his students, many of whom lost their homes and parents.
"You can have your whole life making money," he said, "but a lot of people would pay a lot of money for my experiences."