A 70-year-old wooden hut for scouts and guides in Menai Bridge on Anglesey is getting a £350,000 brick replacement.
Part of the cost involved is due to the location of the hut on a steep slope near Thomas Telford's suspension bridge.
Over 120 children and young people go to beavers, cubs, scouts, explorers, rainbows, brownies and guides in the hut every week.
The new 'eco-friendly' building should be ready by Christmas.
Scouts and guides have been meeting in Menai Bridge for over 100 years - 70 of them in the existing building.
But the 'dilapidated' wooden hut, built on brick pillars, is beyond repair or upgrade, and has no facilities for people with disabilities, according to Malcolm Rogers, chairman of the management committee.
"The project is to provide a replacement building to be used by the scouts and guides and to serve as a community groups and individuals," he said.
"It involves the clearance of the existing site and the erection of a new building that fully complies with modern specifications for multi-use buildings, including being accessible to all."
Mr Rogers said the plans for the new building had to be sympathetic to its location within a conservation and residential area.
"As the current building is up on stilts, it was rather like a drum, and some residents complained about the noise after any of the more energetic activities," he said.
It will have eco-friendly features such as photovoltaic panels on the roof to produce electricity - with any spare being sold back to the National Grid.
It will be available for community use by other groups or individuals.
"We needed a wide hall too, so the roof needed to be lightweight and we've gone for cedar shingle tiles," Mr Rogers added.
The project has received funding through the rural development plan for Wales 2007-2013, which is funded by the Welsh Assembly Government and the European agricultural fund for rural development, as well as grants from the community faciltiies and activities programme and Anglesey Council.
It is expected to be completed by Christmas.
Meanwhile, the members have had to find alternative venues to meet in.
Brownie leader Gay Jacob said: "Between all of our groups we have over 120 young people involved in our meetings each week and it has been difficult to find suitable meeting places to enable continuity during the construction work.
"It really shows the need for additional community facilities," she added.