Generous use of timber, simple exteriors and cantilevered decks or floors suspended above the landscape - these are some of the hallmarks of two exciting new Auckland houses.

Places on Waiheke Island and the North Shore won the 2011 NZ Institute of Architects awards for the Auckland area and were among 42 award-winners across all new buildings.

The Waiheke house is in a country setting overlooking the water and the North Shore house is squeezed on to a beachfront section under sprawling old pohutukawa.

The outstanding houses show how top architects are responding to dramatic settings and how they see their role in leading residential design.

The most theatrical and sprawling is Korora, named after the native Little Blue Penguin. The fortress-style house, which sits on a hill above Matiatia on Waiheke's northern rural edge, was designed by Daniel Marshall Architect - "a stunning and challenging context in which to design a home", the judges found.

Marshall worked with the ridge to minimise the building's impact on its site instead of making a glaring anti-landscape statement. But he did not want the place to morph completely into the hill.

"If you pretend you are trying to hide a house, it looks more conspicuous. As you get up to it, it's quite dramatic. We were trying to get it to look like a landscape element, like a piece of sculpture," Marshall said.

A cantilevered deck with a weir pool floats over the top of the hill and the roof-line lies flat and low with wide eaves, all presented in neutral tones to blend with the landscape.

Marshall picked materials inspired by the island itself: the masonry forms spring from gun emplacements at the historic and popular Stoney Batter while cedar and plywood reflect the kind of precarious weekend baches scattered over the island.

"The clients are returning to live in New Zealand after a long period in Asia," the judges said, noting clever interconnecting rooms and courtyards laid across the ridge that open to the views and towards the land "offering retreat from the sun and allowing cooling breezes to infiltrate the interiors".

Marshall said the house, built by Precision Construction, was restful and Buddha statutes were prominent.

"I spent a lot of time in Asia and the thing I love is the harmony and flow of interior to the exterior. The house is amazing - when you go there, it's very peaceful. It settles you down," he said.

"It has four different conditions: on the southern site, most of the property is covenanted in regenerating native bush. As you go up the hill, it's pasture which has been left intact. As you drop down south, you overlook the northeast across olive groves and grapevines. North is the coast and sea."

Interior living area floors are Australian tallow and paving is 4cm thick travertine.

"I am proud of it - I'd be prouder if I actually owned it!"

The second award-winning house at the end of Minnehaha Ave, Takapuna, is on an almost impossible site: mostly volcanic rock, steep with a 1:3 gradient and home to a grove of old scheduled pohutukawa trees. But the brief did not faze Pete Bossley, who also won an award for an artist's residence in the grounds of Colin McCahon's former home in Titirangi where he had to work around trees.

In both cases, his designs worked with, rather than against, the flora.

"Five pohutukawa were protected and we had to map the roots and then avoid them for the foundations. It was designed in a careful way, having a minimum number of footings which are quite shallow and there's a watering or irrigation system for the tree roots. Five arborists were involved and some argued the trees should be cut down because they may be going to fall down at some time. I think it took two years to get a resource consent," Bossley said.

Building so close to the swaying limbs meant some branches had to be propped up.

"We allowed enough tolerance for the trees to move, how much the tree trunks bend. It was similar at Titirangi with kauri."

The site, which was empty for years, had such a steep driveway that a turntable had to be used.

"It was bloody difficult, it had a lot of things going against it. Other architects had designed houses for the site but the owner said 'Just design what you can get on it'."

The result is a double-car garage, three bedrooms and a library like a child's tree hut, set apart from the house, accessible via a bridge.

The library is projected out to the sea, propped on asymmetrical steel columns. Much of the ground floor slab is suspended on foundations and the house has been squeezed under, around and in between.

Orthogonal spaces on the ground floor rise to a more organic shape towards the top of the house. The main bedroom opens out on to a rooftop terrace which weaves between branches, letting the trees take centre stage.

The judges said what first appeared as whimsical was a clever and controlled architectural response to the intimate natural environment.

AWARD WINNERS

Korora sits on top of a hill on Waiheke Island and features expansive views overlooking the water. The Takapuna house used plenty of natural timber and worked around the pohutukawa trees on the site.

The New Zealand Institute of Architects gave out 42 awards for buildings in Auckland including:

* Korora, Waiheke Island by Daniel Marshall Architects.

* Takapuna house by Pete Bossley Architects.

Source: NZ Institute of Architects