A house designed for the tropics.

4 August 2014 — Cairns Regional Council has released a guide to designing and constructing more sustainable homes in the tropics. Developed with input from some of the region’s leading architects and designers, the Cool Homes Guide – Smart Design for the Tropics aims to assist home buyers, homeowners and builders with region-appropriate principles and detailed checklists.

The release of the guide is being supported by a series of workshops for both homeowners and the local building industry.

The first of the industry workshops saw 50 businesses from the Cairns region attend a session presented by People Oriented Design’s Shaneen Fantin with Russell Parnicott, Cairns branch manager of the Housing Industry Association as a feature speaker.

“Perceptions are changing in this area,” Mr Parnicott said. “We are finding that more builders are investing in sustainable projects.

“The consumer is asking for a new type of housing design for the tropics that suits the climate.”

Terry James

Council’s Planning and Economic Committee chair Terry James said the “hip pocket” was one of many reasons people chose sustainable design.

“A sustainable home is an affordable home,” Mr James said.

“If the home is well orientated to the breezes and sun it will be more comfortable and also reduce the demand for airconditioning. The demanding is increasingly for homes that cost less to run, especially with rising electricity costs.

“There is an appetite for new ideas and new ways of thinking to challenge how things have traditionally been done. Some of the perceived barriers like affordability of sustainability features and lack of locally relevant information in the community and industry have been addressed in the Cool Homes Guide and workshops.

“One of the comments from a workshop participant was that it doesn’t cost any more to face your house in the right direction to capture a breeze or keep out the summer sun.”

The guide addresses the topics of orientation and ventilation comprehensively, including providing diagrams of optimal orientation on the site and optimum room layout within the building envelope. Considerations such as not placing laundries or garages where they will block breezeways, where to place louvres so as to maximise cross-flow ventilation, and the use of roof cavity ventilation for cooling and for mould prevention are discussed.

One of the major concerns in structural terms for the tropics is cyclones, which can make the solid concrete-block type construction seem a better choice. However, concrete block will absorb considerable heat that is then radiated into the home through the night. Wide eaves to protect against direct sun and solar gain, combined with vegetation and the use of nighttime ventilation to purge heat all become important in reducing the radiant heat effect.

The guide points out that lightweight construction, such as insulated timber homes, where appropriate tie-downs have been completed to the ground, can perform well in cyclones. This also has the advantage of making it easier to achieve a raised style of home construction that allows for the cooling benefits of an under-floor gap between the home and the ground-level or slab.

For any type of home construction, the benefits of light-coloured walls and roofs, and the use of vegetation are highlighted, as both reduce the amount of absorbed heat and the radiant heat effect.

As well as detailed information on maximising the benefits of orientation, shading, and designing for maximum natural ventilation, the guide outlines the key aspects homebuyers and house designers should look at to ensure sustainable material choices and a healthy indoor environment.

These include choosing paints and finishes with low or no volatile organic compounds (VOCs); selecting E0 (formaldehyde-free) laminates and composite wood products for joinery; and looking for physical barrier solutions to termite protection rather than chemicals.

There is also a suggestion to look into using recycled materials, including recycled insulation products, recycled plasterboard and wood-substitute products made from recycled plastic.

Energy efficiency – including lighting, pool pumps and appliances – renewables and hot water systems are explained, as are the various insulation options.

You can download the Cool Homes Guide here.