Southland's Charity hospital has reached another milestone with the Armagh Street building now fully enclosed and watertight.

As we move to the next stage of the build we are now able to have multiple trades on-site completing work throughout the hospital as the internal fit-out starts in earnest, organiser Melissa Vining said.

Tradesmen install a window at Southland's Charity Hospital. Photo: Supplied

Since the project began we have been collecting volunteer details and creating a database of volunteer tradespeople such as plasterers, electricians, carpenters, joiners, and painters, she said.

"I would like to personally thank all those who have already donated their time and skills to this project, we wouldn't have been able to get this far without you all."  

Tradespeople who have volunteered will be contacted in the coming weeks to check their availability and organise a schedule, she said.