Festung Guernsey took on the St Andrew’s site two years ago and has been opening it up to more users and events, but the group has struggled with its outdated infrastructure.
The site’s director, Steve Powell, said they had decided not to open the hospital this year because part of the season had already been lost and this would now give them more time to get on with the upgrades.
The workers will also get to enjoy slightly drier working conditions in the summer compared with the winter.
‘We want to take the tunnel back to the bones at the entrance, so there will be a new ticket desk and shop,’ he said.
‘We are quite busy up there at the moment.’
The hospital and ammunition store is the largest surviving wartime structure in the Channel Islands and was still not completed when Guernsey was liberated. It could have accommodated up to 800 patients.
The site owners originally opened the site to tourists in the 1950s and built a wooden ticket area and a paper display.
However, the damp conditions rotted the wood and paper.
Mr Powell said they would be creating a new entrance out of a composite material which will not deteriorate in the damp.
It will also be used as the entrance and exit when the site reopens.
The hospital was designed to be self-contained during the war and at that time included a cinema.
Mr Powell said they had no pictures of what the cinema would have looked like, but there were still hooks where the original screen was once hung, so they planned to recreate the area and show wartime films.
The first will hopefully be about the Occupation.
The team working on the building were able to get permission to work on the site towards the end of lockdown.
Mr Powell said that over the last couple of months they had been upgrading the wiring, which will allow them to have internet in the hospital for interactive boards.
‘There was 700 metres of cable to just get to one of the areas,’ he said.
‘I think we have used maybe two kilometres of cabling over the last few months.’
He said the exact cost of the project was not known yet, but it was tens of thousands of pounds. The work is being funded through the last two years of ticket sales.
Although the facility is closed, special events and booked tours can take place on request.
Mr Powell said that they were already organising for a mountain bike event to take place and anyone interesting in using the site for an event should get in touch.