Welcoming warmth in Wakefield

02:01, Jun 21 2012
Sjef Lamers near one of the concrete tilt slab panels showing through the double glazed window on the north facing side of the house.
COMPACT: Sonja and Sjef Lamers' home in Pigeon Valley, Wakefield.
The bathroom at Sonja and Sjef Lamers home at Pigeon Valley, Wakefield.
An internal window in a bedroom looks out towards the hall, office and living room
Inside the living space showing one of the concrete tilt slab panels, left, which absorb heat during the day then radiate warmth into Sonja and Sjef Lamers home during the evening.
An interior view of open plan living at Sonja and Sjef Lamers' home.
SONJA AND SJEF LAMERS: They have a warm, comfortable home.

Most of us like the idea of working from home. The convenience and flexibility it offers appeals, as well as setting one's own hours of work.

But one of the most off-putting aspects is the expense of heating the house and specifically the workspace during winter.

For Sonja and Sjef Lamers who run their home business, Sustainable Nutrition, it was a top priority to have a low-cost option for heating their home and business premises. They also wanted a warm space for themselves and visiting grandchildren.

Coming from the Netherlands in 1986 where homes were small and centrally heated, they first lived in a cold, damp timber home in Tapawera, so were even more motivated to build a warm home on their land in Pigeon Valley just out of Wakefield.

When working with Architect Peter Olorenshaw they were keen to have a small house that could use as much solar passive heating as possible, given that our winters may be cold but are also sunny.

Peter spent a lot of time walking about their one-hectare property observing the sun's position, the proximity to neighbours and the direction of rainwater runoff, before choosing the best site to meet their criteria.


The resulting house is a compact 127-square-metre, two-bedroom with open plan office, with large north-facing windows, including high clear storey windows, allowing plenty of sun into the building during winter.

This also allows the tile floor over the concrete pad to absorb heat, plus the wall dividing the main living area from the bedrooms and office area is adobe brick which absorbs warmth in the day and radiates this back out during the evenings.

For Sonja and Sjef their favourite aspect in the house are the two floor-to-ceiling non-vented Trombe walls in the main living space – named after French inventor Felix Trombe, who designed a vented system in the late 1950s whereby a 10 centimetre to 40cm-thick masonry wall with a dark heat-absorbing surface (usually painted black) is built behind north-facing double glazed glass.

Heat from sunlight passing through the glass is absorbed by the dark surface as well as in the gap between the glass and the wall. Vents at the top and bottom of the wall are opened to circulate air around the wall and transfer this into the house by convection air movement.

In the case of the Lamers' non-vented Trombe walls, which are essentially large thermal masses, heat takes eight to 10 hours to move through the tilt-slab concrete then releases warmth slowly for many hours after the sun sets.

Rooms heated by a Trombe wall often feel more comfortable than those heated by forced air because of the large warm surface providing radiant comfort. Built on an insulated concrete pad this also has an added "wing" of polystyrene insulation on an angle sloping out from the pad, so as to minimise cold air and dampness creeping into the house.

Framing is untreated douglas fir, with a 150mm cavity instead of the standard 100mm, with ample insulation using wool block.

The exterior is clad in corrugated colour steel on the north side with board and batten in lawson's cypress on the east, west and south sides.

They tried to use locals as much as possible for the build, with Wakefield-based Brian and Tony Bashford coming on board as their building team.

Roger Davies was their kitchen designer and made the kitchen from solid poplar finished with a varnish from Motueka-based Natural Varnish Company.

Richmond company Thelin made the two tilt slab concrete walls and Solid Earth of Wakapuaka supplied and laid the adobe bricks.

Being rural, they had to rely on providing their own water so installed two 25,000-litre water tanks with low-flow shower heads at 4 litres per minute – a standard showerhead uses about 15 litres.

They also have a wood burner with wetback which heats their 180-litre hot water cylinder.

They are keen gardeners and Tree Crops Association members with Sjef and Sonja also trialling seedlings of argentinian/brazilian feijoa crossings as part of their consultancy in soil and plant nutrition.

For storage of harvested fruit and vegetables they have a large pantry/cool room off the kitchen which is well insulated and has two small windows on the south wall for ventilation.

Peter designed a "bridge insulation" feature which keeps the cool room at low temperatures, regardless of how warm the kitchen may get.

Sitting in this warm home on a winter afternoon is a pleasurable experience, and understandably makes for a work environment many of us would gladly swap the corporate office in town for.