A Sydney architect thinks he has the answer to increasing suburban density: put granny in the pool. Sean Radford’s design for a granny flat or separate dwelling sees grandma bunking down in a semi-submerged apartment.

The design, by firm Nobbs Radford, granny could quite literally be pushing up daisies as the roof of her new apartment would be covered in turf.

The benefits, said Radford, are that homeowners can extend their properties and achieve the autonomous space of a granny flat, studio, wine cellar or other space, while maintaining their garden. As Sydney faces another dry summer and water shortages, the design could be a welcome way to utilise dry pools.

“The green roof and thermal properties make it quite a sustainable design,” said Radford. “It’s keeping the best aspects of the suburbs but increasing density.”

Far from being “dark” and “cavernous”, the design could provide a “bright, intimate space”, Radford said.

The configuration includes a sizeable courtyard and highlight windows at one end. Light enters from various sources and, because the footprint is relatively small, light reaches throughout the design. “One side has got a pond. From inside you would see this through a window, providing filtered light,” he said.

Manfred Wiesemes, NSW president of the Swimming Pool and Spa Association was unenthusiastic about the idea, describing the plans as “impossible, in one word”. Empty pools, he said, could “float” when rain saturated the soil.

But Radford refuted this claim, saying the roof would weigh the pool-cum-home down. “The Swimming Pool and Spa Association has its agenda,” he said. “I’ve not got a grudge against pools,” Radford said “I know pool owners and I’ve enjoyed swimming in their pools.”

Planning laws are “problematic” to the pool rehabilitation Radford said. “All planning laws are restrictive. We acknowledge the rationale behind some of them but when we’re looking at things like density we need to re-look at those laws and how they could be applied to certain schemes.”

The Department for Planning said it was looking at a policy to encourage granny flats, but it decline comment on the potential merit of putting one within a swimming pool.

Radford denied the proposed design was a ploy for media attention or an abstract architectural exercise. “It had a certain amount of play in it but it was also something we thought could be taken further otherwise we wouldn’t have proposed it.”