It's by far the newest addition to 30 Cork Street, home to the heritage-listed Gundaroo Store and Sally Paskins Store, both more than a century old.

While many travellers may be able to recall the slab hut hidden behind climbing roses or the time-worn facade of the larger store, not many would be acquainted with the people behind the landmarks, Peter and Jenny Thorne.

The couple have owned the sites since 1975, during which time the main building has operated as a tea house, gift shop and even a restaurant. Dubbed the Bush Spit, the eatery served a three-course spit-roast meal for $16, all of which was cooked in the back room - two lambs and 14 chickens at a time.

Mr Thorne said the 37-year-long endeavour started when they made their tree change south from Gladesville, stumbling across the unique property almost by accident.

He said the main store and smaller slab hut, built circa 1893 and 1886 respectively, caught their attention at once.

''We had a little stone cottage in Sydney which we spent six years restoring, so we've had a long-term interest in old buildings,'' he said.

But buying a heritage-listed property isn't as easy as handing over cash and taking the keys - Mr Thorne said it was a sizeable responsibility to take on a piece of history and keep it intact.

''You've got to be terribly careful,'' he said. ''Originality is absolutely beyond everything else. You can't muck around with things and destroy the history.''

He said attention to historical detail had been fundamental to the upkeep of the properties over the past four decades.

The walls of the slab hut had been plastered with news pages reprinted from the era in which it was originally built, while outside the main building a set of doors still bore the original paintwork from more than a century ago. ''It was painted once in 1893 and it's never been touched,'' Mr Thorne said.

''We'd never dream of repainting it. People who do this stuff are terribly conscious of these sorts of things. If they repaint, they go right back to pigments.''

However, there had been some changes made to the main building, with windows installed in the back room - but even then, the cedar frames were meticulously sourced from Macquarie Street in Sydney.

All the restoration work has been undertaken by Mr Thorne himself since the pair bought the property, a habit he hopes will stick with the next owners, who are likely to pay more than $1 million for the property.

Mr Thorne said the growing amount of media dedicated to the restoration of historic buildings had helped boost the popularity of heritage properties, but there were potential downsides.

Chairman of the ACT Heritage Council Duncan Marshall said it was important that people buying a heritage-listed property understood why it had been listed, as the heritage values could limit what owners could do with the building.

Mr Marshall said the owners would also be charged with maintaining the property's heritage value, although that could be as simple as keeping paintwork up to scratch.

''In most cases, that may be no more than maintaining the place in the way you would maintain any property,'' he said.

''Quite a lot of conservation is really just maintenance.''

Across the border in New South Wales, councils such as Yass Valley offer property owners grants to help cover the proposed costs of maintenance works such as painting, repairs and structural works that will extend the life of properties.

Similar heritage grants are available in the ACT, though Mr Marshall warned that the funds were limited.

He said there also were restrictions in what you could do with heritage properties, in terms of extensions and other changes, but most owners were happy to work within the limits.

''By far the largest number of heritage-listed places in the ACT are houses, and people are always changing their houses in little ways,'' he said. ''It's a case of how you do it, rather than what you do.''