The old hall – an ex-RAAF demountable wooden hut – stood on the Kaleen property for more than 30 years. However, the building was targeted by teenage arsonists in 2010, leaving the Diamantinas to rebuild what was lost through painstaking fundraising.

"It is so surreal because we had to build basically on the footprint of the old hall. So it's sitting there and it's different but it's the same," Sue Groves, scout leader and rebuild committee member, said.

Through sausage sizzles and badge sales, the group raised more than $20,000. The Scouts ACT branch, the Rotary Club of Belconnen and in-kind work made up the $130,000 needed to start over.

However, not everything could be replaced. When the hall was doused in petrol and set alight, it was full of three decades' worth of honour lists, relics and flags from interstate competitions; even an old cow skull signed by former scouts.

"We lost all our memorabilia. There's not monetary value in any of it but . . . that's what we have to build up again," Ms Groves said.

The honour board that recognised Diamantinas who had achieved scouting's top award, the Australian Scout Medallion, was also damaged in the blaze. The committee has searched through records and scouts' histories to find the names and recreate the board.

"We tried to make sure that even though we've got a new hall, we've still got that connection to the history of the old hall and all the things that happened as part of that," rebuild committee member Sam Cavalli said.

While some younger members haven't fully grasped what it means to have their own space, for others, like Ms Groves who has been involved with the group for two decades, it's a return home.

She said the future was bright for the Diamantina Scouts.

"It's one of the oldest groups in the ACT; it's kept on going through all of this. It's giving [youngsters] something to think about and do, rather than setting fire to scout halls at two in the morning."