Saturday, 15 September 2012

Further Thoughts on Sustainable Design

Sue Roaf in her excellent book "Ecohouse" says:

"Your ecohouse design needs to be not just comfortable to live in but it has to remain habitable and safe despite the worst predictions for climate change. The future of the people that live in the house may depend on whether it stays cool in summer and warm in winter and to what extent it can do this without "outside" help in the form of energy from the gas main or electricity grid."

ie "A building that uses a minimum of energy and preferably generates its own energy."

Local concrete frame (earthquake requirement)
Particular design issues she raises are:

- Aim for a dwelling that uses the minimum amount of energy to run. This can be supported by applying conservation techniques and passive solar design principles. The use of solar hot water and photovoltaic systems is highly desirable to generate on-site energy.

- Local building materials (and expertise) and those requiring the minimum of processing should be selected in preference to highly processed materials and those from further afield.

- The durability of materials is also very significant as it will affect the lifespan of a building.

- The potential for flexible occupancy will help to extend the useful lifetime of a building.

Local building expertise

She further notes:

- the use of concrete floors and high density concrete blocks for walls as suitable materials for thermal mass.

- double or triple glazed windows with low emissivity coatings.

- as a rule of thumb (in UK) 150mm insulation in walls, 250mm in roofs and, say, 100mm expanded polystyrene under a concrete ground floor are considered to result in a "super-insulated" house.

- ventilation and insulation must be considered together since no point in heavily insulating a dwelling if it is not airtight. Adequate background ventilation, usually through trickle ventilators built into window frames is essential for health and condensation avoidance.

The above comments had a particular resonance with where       my design thinking had reached given my many months of background reading and research in designing my earth-sheltered, off-grid, solar passive, high thermal mass house in Crete. I found  Sue Roaf's book particularly useful since, like a pattern language (see earlier post) it did not present a particular solution to design but presented many case studies backed by scientific reasoning that enabled me to better understand the issues and formulate solutions to meet my particular requirements.

Design after a number of iterations


"Ecohouse" - Sue Roaf, Manuel Fuentes, Stephanie Thomas.