The work will take place at Cannon Hall Museum, Park and Gardens’ north range glass house, one of the oldest of such structures within the site’s walled garden.
Barnsley Council has agreed to put £209,000 from its capital budget into the work and accept £50,000 grant funding from the Wolfson Foundation.
Plincke Landscape will be principle designer on the project with a contractor appointed at a later date.
The work comes at the tail end of the Parks for People refurbishment programme, a £3.8m scheme to renovate Cannon Hall’s buildings, improve the landscape and open up previously lost vistas, as well as reopen the park’s Georgian lakes.
The building became unused after the Second World War and fell into disrepair, but last year work started to improve its structure - with a new roof, windows and doors.
Earlier this year, new pieces of glass were installed at the front of the glass house.
Plans are to renovate the interior of the building, for it to become a new learning space scheduled to open next year.
Coun Tim Cheetham, cabinet spokesperson for place, said: “The new training and a creative space at Cannon Hall Museum will have a huge impact on young people across the borough. It will also offer an opportunity to learn more about the Hall, its collections and links to Barnsley.”