L'Institut des Freres des Ecoles Chretiennes has gifted the crumbling, iconic building and surrounding grounds to the new Little Chapel Foundation.
Foundation chairman Pat Johnson said underpinning the building had cost about £70,000.
Around £80,000 more was needed to stabilise the foundations and weatherproof the building and the exit.
This money has been loaned to the foundation and fundraising will start soon. But the work has to be carried out now.
In the long run it is estimated the site needs £500,000-worth of work.
More than 80,000 people visit the Little Chapel every year, making it the most visited attraction in the island.
Mr Johnson said Guernsey should not underestimate the site's importance.
'It is a place of international renown and is Guernsey's premier tourist attraction,' he said.
'I am extremely grateful that the councillors of the foundation have all agreed to provide their services free of charge and would give particular thanks to those professional bodies that have already rendered their services free of charge,' he said.
'Every penny that is raised will go directly to the restoration of the Little Chapel.
'Once this work is completed, we will begin on the supporting facilities.
'We are starting from a negative position because we have had to borrow money to carry out the immediate emergency work.'