The tall brick building on Lawrence Hargrave Drive is planned to have a new single-storey "pavilion-style" extension to the rear of the school with disabled access, under plans submitted to Wollongong City Council.

Treasurer of the school Alison Wiig said the not-for-profit was given a bequest by the late Shoalhaven philanthropist Warren Halloran after he died last year, which sparked the process for the addition.

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Northern Illawarra architect Tim Antiohos jumped onboard to draft the plans "pro bono", crafting a multi-functional gallery space, store room, plus disabled toilet and access using sandstone, hardwood, glass and steel.

Committee member David Roach said they didn't want the addition to take away from the beauty of the heritage building, but also wanted the design to reflect the community.

"We wanted to reflect the fact we are innovative, we are open and creative and encourage cultural diversity," Mr Roach said.

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Built in 1911 on land donated to the community by the then Clifton Mine, the two-storey brick building was designed by architect Stuart Leslie Elphinstone and included a reading room, library and two offices.

The original plan was also to have a large hall at the rear but it was not part of the initial construction due to changed economic circumstances of the area, according to the NSW Office of Environment and Heritage.

Currently the back door of the school stands more than a metre above the ground and opens to a garden below.

Ms Wiig said the new hall would allow them to host an exhibition or wedding on a weekend without disrupting regular art classes or meetings.

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The new pavilion has been designed with "a minimalist approach to form", according to the DA, with a flat roof which seemingly "hovers over the landscape".

"[The roof] is supported by steel cruciform columns ... pencil like sculptures, that not only serve as structural elements but is also symbolic of the long history of steel making in Wollongong," the application states.

"The enclosed space strengthens the notion of a floating roof by providing highlight glass between the underside of the ceiling finishing at the top of entry doors and canopy."

In the past the community building has housed a library, a reading room, a general store, a billiard room, a post office, an electoral office and a dance hall for the miners of Scarborough and Clifton.

"Over the years the building deteriorated badly and it looked as though it would have to be demolished however finally in 1996, a new School of Arts Committee was formed and fundraising and lobbying for the restoration began," states the school's website.

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Ms Wiig said the generous bequest won't cover the entire cost of their new addition, so the committee would begin investigating fundraising opportunities and government grants once the development application is approved.

A DA for the new pavilion is currently on public exhibition through Wollongong council's website until April 1.