"It was within walking distance of the office but, for work-life balance, you don't want to live so close," says Chan.

So, four years ago, the couple, who have two sons, Tom, seven, and Sam, 10, decided to look farther afield. They settled on a 1,000 sq ft flat in One Beacon Hill, a luxury housing estate in Kowloon Tong. Instead of a concrete jungle, their new home overlooks a verdant hillside and has a spacious balcony that faces the sunset.

"In the morning, you can hear the birds singing," says Ng. "Before, I thought you could hear that only in the New Territories."

The couple hired Frankie Lam, of Bugs Design Consultants, to revamp the space, creating features including a glass-walled study for the boys. Then, last year, an unexpected opportunity arose: the flat immediately above went on the market.

"With one floor, it was comfortable enough but, as the boys are still growing, we wanted more space," says Chan.

The couple bought the unit and asked Lam to merge the two properties into a three-bedroom, 2,000 sq ft duplex.

"The procedure was not as complex as we thought," says Ng.

Lam hired a Buildings Department-approved "authorised person" to oversee the construction of an internal staircase between the two apartments. The renovation took six months and involved a near-total reconfiguration of both floors.

Upstairs, Lam converted what had been a living room, dining area and kitchen into an extra-large master bedroom and en suite: "They wanted it to feel like a hip hotel," he says, citing the entertainment centre, work desk, for late-night conference calls, and minibar.

"We tried to make the bedroom self-contained," says Chan. "Sometimes at night we sit on the balcony. It's a nice place to enjoy a cigar."

Highlights in the master bathroom include: a walk-in wardrobe, a dressing table and a 30 sq ft shower area that includes a large standalone bathtub that appears to hover above the ground, thanks to a central pedestal. A large swinging door between the bedroom and bathroom is flush to the wall when open, so the two spaces appear seamlessly integrated.

Between the master bedroom and the staircase is an open study for the boys, with built-in cabinetry and a glass whiteboard. The boys share more than just the workspace; their bedroom is next door and includes its own bathroom, which has a frosted wire-glass door that reminds Chan of one in her childhood home.

Downstairs, the boys' old bedroom and workroom were demolished to double the size of the living room. A storage unit was built underneath the staircase while the old master bedroom was converted into a multi-functional space with a sofa bed and mahjong table.

Everything but the kitchen and one bathroom was changed, says Lam.

Chan says her main request was for the design to be simple and modern, partly so she and Ng could showcase their extensive collection of lighting fixtures.

"We have more than 20," says Ng, adding that they range from Murano glass items to modern pieces, including one that casts dramatic shadows that resemble torn paper. Chan put it above the stairwell and painted the wall grey to enhance the silhouette.

"It's like a piece of art," she says.

Living room The cabinet under the television (HK$31,000) was supplied by HB Collection (3/F, Kar Chau Industrial Building, 6 Sheung Hei Street, Kowloon, tel: 2117 0858) while the standalone speakers and subwoofer were from Bang & Olufsen (IFC Mall, Central, tel: 2918 0007). The black coffee table (HK$22,000) came from Ligne Roset (16 Blue Pool Road, Happy Valley, tel: 2891 0913) and the egg-shaped stool (HK$3,500) was from Lane Crawford Home Store (Pacific Place, Admiralty, tel: 2118 2288).

Dining room The dining table (HK$39,000) and pendant lamp (HK$31,500) both came from HB Collection. The dining chairs (HK$3,510 each) were from Kartell (46 Wyndham Street, Central, tel: 2810 0408). The stairs were constructed by New Fortune Decoration (12/F, Kin Fat Industrial Centre, 13 Kin Fat Street, Tuen Mun, tel: 9340 6696) and, including the services of a Buildings Department “authorised person”, cost HK$314,000 to install.

Master bedroom The two silver adjustable reading lamps (HK$4,896 each) and the pendant lamp (HK$9,936) all came from Apartment (62 Leighton Road, Causeway Bay, tel: 2882 2198). The black wall lamp (HK$1,920) came from Artemide (Ruttonjee Centre, 11 Duddell Street, Central, tel: 2523 0333). The bed (HK$35,000) and desk chair (HK$16,000) both came from HB Collection. The desk (HK$14,985) came from Posh Office Systems (3/F, Warwick House, Taikoo Place, Quarry Bay, tel: 2169 9231).

Study Custom-built shelving and desks provide plenty of room for schoolwork. The bookcase (HK$19,800), desk (HK$12,870) and shelves (HK$10,750) were built by New Fortune Decoration. The chair/stairs are the same as the one in the multi-functional room. The silver chair (HK$7,000) came from Aluminium.

Bathroom The desk cost HK$14,000 from HB Collection. New Fortune Decoration built the wardrobe for HK$57,024, the basin cabinet for HK$7,095 and a floating mirror for HK$8,800. The wall lamp (HK$2,780) came from Zodiac (32 Morrison Hill Road, Wan Chai, tel: 2832 9987). The make-up mirror (HK$3,880) was from Oscar (342 Lockhart Road, Wan Chai, tel: 2988 1904). The silver chair is the same as before. The wavy tiles (HK$228 per 40cm x 80cm tile) on the feature wall came from La Casa (175 Lockhart Road, tel: 2511 7880). The mushroom-like wall hooks were bought for a total of HK$1,580 at Flea + Cents (8/F, BT Centre, 23 Wong Chuk Hang Road, Aberdeen, tel: 2528 0808).

Boys’ bedroom Tom and Sam chose the wallpaper (HK$4,900) for their room at Wallpaper Plus (9/F, The Hennessy, 256 Hennessy Road, Wan Chai, tel: 3525 1785). The leather monkey cost HK$5,500 at Lane Crawford Home Store. The beds (HK$7,000 each) and wardrobe (HK$58,080) were built by New Fortune Decoration while the bedside table (HK$1,000) came from Kartell. The silver wall lamps (HK$1,150 each) were from Artemide.

TRIED + TESTED

Inspired by a filing cabinet at his own studio, Frankie Lam, of Bugs Design Consultants (27/F, Winsan Tower, 98 Thomson Road, Wan Chai, tel: 2866 0279), designed this plywood storage unit for Tom and Sam's room and had it built by New Fortune Decoration for HK$58,080. Each cabinet has a slot for the boys to insert their own labels.