OASIS IN THE CITY

Holt Street springs into life with a refit complete with tranquil green roof. 

Nestled in the heart of Sydney is a surprisingly beautiful, tranquil oasis. Holt and Hart at 50 Holt Street, Surry Hills has been injected with a new lease of life through a complete refurbishment coupled with the establishment of a lush and creative 1300m² rooftop garden.

Holt & Hart residential building had two large upper level areas suitable for roof garden environments. Developers, Cornerstone Property Group awarded the construction contract for refurbishment to Mainbrace Contractors. A vital component of the success of the design of the garden areas was Elmich’s range of innovative landscape engineering products.

“We aimed to create attractive, colourful and low maintenance functional rooftop garden areas,” explains Mainbrace Constructions project manager, Michael Fague.

The intense heat of Australian summer is a huge challenge for urban green roof designs. Elmich employed the use of VersiDrain 25P® drainage and water trays that keep plants well hydrated while eliminating excess water through drainage perforations. The trays are easily installed, enabling water to be stored and reused later. They also provide free drainage of excess water and protect the underlying water membrane.

Geotextile was laid over VersiDrain 25P® followed by growing media, plants, colourful scoria, as well as a range of coloured, decorative gravels.

To allow rapid drainage from the large, shallow planted areas to disperse to drainage outlets, VersiCell® lightweight drainage cells were installed at the perimeter of the green roof. Made from recycled plastic, VersiCell ®protects the waterproof membrane and can withstand heavy loads like large trees.

For large decking areas, Mainbrace selected VersiJack® high strength adjustable bearer supports. Manufactured from recycled plastic and unlike brick, metal or timber support systems, VersiJack® doesn’t damage the waterproofing membrane, rust rot, warp, absorb or retain water.

“VersiJack^® accommodates for falls in the roof slab, are infinitely adjustable and support bearers at heights of 80-1000mm,” Michael Fague explains.

As part of the refurbishment, the roof’s waterproof membrane was replaced. Supplied by Green Roof Technologies and installed by Spanos Waterproofing Evalon, a sheet waterproofing membrane that is both highly UV and plant root resistant was employed.

“All the elements used in the construction of the roof gardens were specified because they deliver visually appealing, highly functional and low maintenance recreational space areas,’” Michael Fague says.

The results – a tranquil place to unwind for busy urban dwellers.

PROJECT PARTICULARS
Developer Cornerstone Property Group
Construction Contractors Mainbrace Constructions
Green Roof Components Elmich
Waterproof Membrane Green Roof technologies/installation Spanos Waterproofing