We were the first to review the text at both Amazon.co.uk and Amazon.ca, though Amazon.com has so far declined our submission.

From Green Roof - A Case Study:

... In the search for technical solutions, the rationalists always answered the question of how to build a green roof by looking at new materials and technologies, as well as the employment of new substances for roofs and soils. The opposing faction argued that flat roofs leaked and that even a child knows that a proper house has a pitched roof. This controversy, led by technical mock arguments between modernism and traditionalism, was finally ended by the rather cumbersome achievement of technical perfection. Flat roofs are in the meantime up to par even in climates with long winters and rainy summers. - Peter Latz, Amertshausen, January 2007, Introduction, p. 15)

'Technical perfection' -yeah, right!

Visit Is Oak Street Vancouver's new Boulevard of Broken Dreams? for some context on Vancouver and technical perfection in green tarped condo buildings.

More Quotes From Green Roof - A Case Study:

Roof gardens and green roofs both belong to a type of roof that supports vegetation. In general, the planning profession draws a clear distinction between the two types. Roof gardens are installed to be accessed and enjoyed. They are the most cost intensive to construct, heavy in weight with deep soil profiles (more than six inches), and maintenance intensive. In contrast, green roofs cost a fraction of a roof garden, are lightweight with thin soil profiles, and require minimal maintenance. Most green roofs are inaccessible, and they are mainly installed for environmental performance and visual improvement. Green roofs are descended from the vernacular architecture of various countries in all parts of the globe, whereas roof gardens are known as luxury items of the affluent since the famous hanging gardens of Babylon (600 B.C.) (From The Reclamation of Roofs, p. 18)

If roof-top use remains a privilege of the wealthy living in historic districts, the democratic promise of the modern movement to build roof gardens for everybody has obviously failed.

Thereby a variety of factors played a role. The biggest factor was and is the considerable additional expense of a roof garden compared to a regular roof. One must not forget that the flat roof is attractive to a developer because it is less costly than a sloped roof. The addition of a roof garden eradicates those savings. It is not the additional cost of the garden that has to be paid for but also the reinforcement of the whole structure that has to hold the weight of the garden. There is also a considerable financial commitment to maintaining a garden that is mostly out of sight from social supervision. For the average developer who has a revenue expectation of seven years, the increase in value of the property through a roof garden does not occur fast enough to be profitable[/color], moving the roof garden into the realm of a luxury item.

Other factors had considerable influence as well, like the exodus of the middle class into low-density suburbs that drained the city of people who could have asked for and afforded a condensed architecture of roof gardens and terraces. On top of this, technical shortcomings like the leakage problems of early roof gardens created an aura of suspicion and avoidance - prejudices that persist up to today. Finally, it has to be acknowledged that a majority of buildings do not have the programmatic need for intensive roof gardens, such as industrial buildings, warehouses, most commercial buildings, and residences in low-density areas with too low a population to profit from a roof garden or with too much open space around.

About 30 years ago, the desolate sight of these bare flat roofs triggered a counter movement in the German-speaking countries of Europe. Methods of exchanging the gravel of ballast roofs for a thin coat (three to five inches) of growing medium were tested. The low weight of the soil made structural reinforcement of the existing roofs unnecessary, thus substantially reducing costs. They also found that the minimal type of a "roof greening" (the direct translation from the German) provided similar environmental benefits as a traditional roof garden. The thin coatings retained and cleaned rain water, cooled and humidified the surrounding air, filtered dust, reduced noise levels, insulated against heat, provided habitat for flora and fauna, and prolonged the life expectancy of the roof. The technology was widely implemented as a remedy against many problems of urban density, such as frequent flooding, water and air pollution, and high energy consumption. (emphasis added) (III The Shattered Dreams of Modernism, pgs. 21-23)

 

What do the experts say about building maintenance and inspections?

More about the already onerous maintenance / inspection / repair / management obligations inherent in condo living here.

Stephan Brenneisen, a Swiss green roof specialist and ecologist, claims that many of the thin substrates on sedum roofs lose their effectiveness over time. Some of the used substrates tend to become acidic and do not sufficiently provide minerals and nutrients for the long term health of the sedum plants. Owners rarely fertilize their sedum roofs on a regular basis and the plants suffer after a couple of years. Brenneisen also found that many sedum roofs have minimal positive effects on storm water retention, energy use or the urban climate - core arguments that have been used to justify the implementation of green roofs. Moreover, ecologists attribute rather limited bio diversity values to sedum roofs and prefer roofs that offer a secondary habitat to endangered plant and animal species.

... Brenneisen believes that his roofs will get richer in biodiversity over the years. He likes to show the potential long-range benefits of his designs by referring to a green roof in Zurich that is now ninety years in service.

The lake water filtration plant Moos built in 1914 was a product of engineering excellence of the time. Water from the lake of Zurich is pumped into the building and is cleaned to drinking-water as it slowly filters through a layer of sand. It was the first reinforced concrete building in Zurich and was outfitted with a nine-acre (3.6-hectare) earth roof for temperature moderation.

During its ninety year lifespan, the roof had to be reworked only on its edges; the rest of the waterproofing remained functional.

The three-inch- (7.5-centimeter-) thick concrete ceiling is sealed with a three-quarter-inch (two-centimeter) mastic asphalt membrane and then overlaid with six to eight inches (15 to 20 centimeters) of topsoil. Today, the roof supports a stable meadow community with 175 different plant species and six thousand specimens of a rare orchid. Many plants are on the endangered or rare species list of Switzerland.

The protected location of the roof and the continuous maintenance regime of the meadow preserved a plant community that does not exist on the ground anymore. (Discuss this project online at Arichitecture Week.) (-- pg. 35)

View the 12-page Report on the Environmental Benefits and Costs of Green Roof Technology for the City of Toronto.

A few of the local challenges we'd like B.C. 'BILLIES to overcome before attempting GREEN roofs or roof gardens, thanks very much.

Green roofs? B.C. 'BILLIES can't be trusted, say insurers: What are insurers telling condo buyers about B.C. 'BILLY construction?

 

Our review of Green Roofs, which Amazon.com has so far declined to post:

The most revealing feature of this book is the author's glaring omission of what experts now refer to as the new 'failed housing economy,' which depends on housing stock pre-destined to fail, thereby requiring major repair/renovation/reconstruction/redevelopment within a period of five to 10 years. Govts worldwide have embraced this type of development, sacrificing consumers to keep the profitable (for some, including the author and his sponsors) real estate wheel grinding along its destructive course.

Notable examples include the leaky condo crisis in Vancouver, British Columbia and New Zealand's mirror-like weathertightness crisis. In places like California, construction failure (usually because of leaks) became so prevalent, the state enacted legislation to give contractors a chance to repair their brand new yet failed building before owners take them to court.

Not surprisingly, perhaps, developer and contractor sharpies, already the stuff of legend in the new failed housing economy, now appear as thick as ants at a picnic, anxious to exploit predictions of global warming and undiscriminating media reports of the new green/sustainability revolution. The question, then, is how to distinguish between fraudsters and legitimate, well-researched solutions?

Books like this one certainly offer no help. Yes, there are examples of champion-sounding projects in places like Germany and Switzerland, but what standards, procedures, technologies and skilled workers would ALSO be required to ensure successful implementation in other jurisdictions - especially those with as yet unresolved issues of epidemic building failure? Quite simply, if the locals are unable to design or construct a building that can at least keep the weather out reliably, who in his right mind would trust them to experiment with anything as costly and maintenance-intensive as a green roof or worse, a roof garden?

Frankly, the omission of any discussion about these essential variables makes this book little more than an exercise in self-promotion for the author and his sponsors as opposed to a fair, critical analysis of complex new procedures. What's worse, it invites authorities, who prefer to overlook rampant building failure, to continue to do so with devastating consequences. How easy it is already to picture governments rewarding the green roof industry with the usual array of business advantages. Sadly, this codswollop will make it even easier.

Books on GREEN roofs and rooftop gardens should NEVER be translated from German unless we import the standards, enforcement and construction expertise imperative to success!

Unbelievably, Canada has tried to flog dubious wood-frame housing (the type representing the bulk of B.C.'s leaky condo debacle) in Germany!

Also see Green roofs? B.C. 'BILLIES can't be trusted, say insurers.

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