As architect Mike Hartley will tell you, an 80-square-metre cottage is cramped for a whānau of five. It’s three children bundled into one bedroom while you share a tiny closet-like space with your wife. “Carnage” is how the director of Tāmaki Makaurau Auckland’s Lloyd Hartley Architects remembers the old two-bedroom home. It wasn’t merely short on space but practicality too. Originally orientated so the laundry enjoyed the most natural light, things had to change significantly — and affordably.

The architect found the solution in a square extension. Grafting a timber box onto the eastern side of the home, he reconfigured the existing layout, before linking the two elements with a new deck. Though the relatively modest addition only expanded the home to 135 square metres, strategic planning allowed Hartley to introduce two more bedrooms, another half bathroom and fresh, sensible circulation.

“The biggest move we made was to celebrate the squareness of the kitchen and dining,” Hartley says of the design. Inspired by old farmhouse kitchens, the communal space features a dining table where you might expect to find an island — a “gentle pushback against open plan,” he says. Two large sliders from First Windows & Doors embrace the outdoor connection. Pulled back, they create a four-metre opening between the kitchen and deck, forming an extension of this central space when friends and family drop by. The new joinery floods the room with light, and its high-performance double-glazing alleviates any fears of heat loss through the floor-to-ceiling doors.

Alongside the kitchen, the laundry has found fresh purpose as a living area, lovingly referred to as the “room of requirement”. It’s a flexible space where the kids watch TV, build Lego, hold band practice or put up any visiting guests. Imperatively, it sits away from the original lounge, AKA the adults’ “withdrawing room”. Hartley prioritised this division between young and old, delivering the separation a growing family often demands.

The design centres around the Hartleys’ unique needs, squaring a modest budget with the most essential changes. Bedrooms were intentionally kept small — big enough “to sleep in and sulk in” — to accommodate a larger footprint in the communal areas, and the outdoor connection took precedence with multiple access points. In the room of requirement, for example, the kids can slip through a generous window straight onto the deck.

While the extension features the likes of a large over-the-wall sliding door, budget wins were made in the original part of the home, where the old draughty windows could be popped out and replaced with new, double-glazed aluminium joinery from First Windows & Doors, then detailed to fit the home’s aesthetic.

The success of this Auckland renovation lies in its specificity. Mike Hartley analysed his family dynamics and routines to deliver a home tailored to their shared life. It’s bespoke on a budget, using cost-effective materials to define the home’s personality, such as the carved door handles and bold, personalised colours that adorn the ceilings and entrances of the kids’ bedrooms. With his boxy extension and thoughtful rearrangement, Hartley has transformed the old home — and the experience of living here — in ways that will serve his family for years to come.