Beacon

Getting rid of damp

High insulation levels and passive solar design in the Waitakere NOW Home® created a warmer indoor environment, less prone to condensation.  Cold air holds far less moisture than warm air.  In cold temperatures the moisture naturally in the air settles on cold surfaces such as un-insulated walls, ceilings and windows as condensation.    Double glazing keeps the inside glass surface warmer, so fogging and condensation (which can damage woodwork, furniture or upholstery) is much less of a problem.

A rangehood extracts moist air from the kitchen, and the laundry is sited in the larger, better ventilated space of the garage.  With no clothes dryer, the tenants were encouraged to dry clothes on the washing line outside, or on a rack in the garage. 

Solatube mechanical ventilation fans in the bathrooms are linked to the light switch being turned on, and run on a timer.  These are particularly important in ensuites where extra moisture can affect the adjoining bedroom.

Passive ventilation

The Waitakere NOW Home® used aluminium window frames with in-frame passive ventilation systems which allow constant air circulation even with windows and doors closed.   

The passive ventilation systems did not prove enough to cool the Waitakere NOW Home® during the heat of summer.  For greater cooling, security stays were fitted to some windows so they can be left open, and a Solar Star ventilation unit was installed in the kitchen.  The Solar Star is solar powered but can be turned off when not needed. 

Photo: Deborah Dewhirst

 

Weathertightness

The Waitakere NOW Home® meets the challenge of creating a weathertight house with good design.   The house has over-hanging eaves to keep wind-driven rain from the wall claddings. The roof has a more-than-adequate slope to shed water. 

Flashings have been installed wherever disparate materials meet.  Joins in materials, and around windows, are often prime sites for moisture penetration into the linings of a home.  Flashings are used:

• around all windows and doors
• where the roof of the entry porch meets the wall
• around the concrete slab and insulation
• wall cladding junctions
• roof valley, barge, ridge and apron flashings

Kiln-dried boric-treated H1.2 Radiata pine was used for wall and roof framing.  This meets the new requirement for treated radiata to be used in external walls and moisture risk situations. Breathable paper wall and roof linings stop moisture and dampness entering the home.

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