Nestled in the Good Class Bungalow area of Bukit Timah, the site - an L-shaped plot with a staggered, sloping terrain and narrow frontage, and surrounded by multiple houses - would have been considered unfavourable by most. However, the architect responded to the challenge with a design that is not only sensitive to, but leverages on, the land conditions.

Lush greenery, striking contemporary geometry, and natural materials are some of the defining features of the Secret Garden House by Wallflower Architecture + Design that achieved the feel of a peaceful, secluded resort after its full potential had been harnessed.

"We saw an opportunity in using the terrain to camouflage the bulk of a large house, and the potential of lush greenery to screen it from prying eyes," says Robin Tan, principal architect of Wallflower Architecture + Design. Over a third of the house was integrated into the rising land profile, with the perceived ground floor set one level up, atop a 'plateau' where the open living spaces and gardens blend into one another.

A roof garden, instead of the conventional roof form, was adopted to "cool the rooms below while functioning as an outdoor entertaining deck that offers views of Bukit Timah Hill", says Tan. In this way, the design of the house minimises visible mass to be less obtrusive, while also reclaiming its 'green footprint'.

The Secret Garden House is home to the Ng family. They own local construction company Progressive Builders, which took charge of the build. Their expertise in the building and construction industry meant that the Ngs understood the constraints of local building guidelines, and appreciated the potential of the site. They easily agreed with Tan on the house design, says Mrs Ng, and allowed him to take the lead, rather than let the family's knowledge of construction get in the way.

Cross-ventilation was especially key, and this is reflected throughout the house. In the basement, air flows into the impressive cave-like garage through the timber slatted lobby and out of the back via a sunken garden courtyard. Above the open ground level, the private areas are passively kept cool by travertine stone cladding, air cavities, pergolas and roof gardens. In front of the windows, timber screens filter strong sunlight and also encourage an ever-shifting play of light and shadow in the interior spaces.

Her favourite area of the house is the ground floor, where the family spends the most time together in the living and dining areas that are linked and interspersed with landscaping. "I think that's because the food, coffee and TV are there, so there's the factor of both convenience and social interaction, and there's also a good calming view of the pool," she adds.

Function-wise, the Ngs had specific requirements for a steam room, KTV room and a multi-purpose room for activities such as dance, group yoga and table tennis. "I wanted a pool - although we haven't swum as much as I thought we would, it gives a very serene view and I enjoy looking at it - and it was important to have a garage that has sheltered access to the main house," says Mrs Ng.

When it came to the materials used, purchases were made mostly through the construction company's contacts.

As modern as it is, the design unexpectedly parallels that of a more historic period. "The inspiration came from local colonial bungalows which are raised on masonry piers," explains Tan. "Under the floor of the main house, a casual living setting leads to the surrounding gardens. The upper floor that houses the family room and bedrooms is more enclosed for privacy and security. There is clear spatial arrangement of enclosed spaces stacked over an open plan; private spaces above public space."

This article was first published in The Peak.