Wednesday, April 15, 2009


Today's paper had a major front page story on green roofs ( Apparently Mayor Millar in Toronto is trying to position Toronto as a green sweepstakes winner. Green roofs have a number of widely recognized benefits (and less widely recognized costs) so Council is considering mandating them on new buildings.

Curiously, they propose to exempt themselves from the rule: their new municipal housing would be exempt, as would schools and, curiouser and curiouser: large commercial buildings. The buildings that would be targeted (ie, forced to install green roofs) include condos and retail malls. Note that both of these types of buildings divide up the cost amongst a myriad of smaller space users. Could it be that the Council is trying to conceal the cost from the payers? This slight of hand trys to hide costs from voters, it's akin to opposing the oil sands out west while Ontario burns coal ... or imposing costs upstream on the producer hoping that the consumer won't realize the cost increase was due to taxes.

It seems to me that large sprawling buildings are a better target: wal marts, factories, and schools (which seem to me to be major polluters, but they go largely uncriticized).

And I find it objectionable that Council is trying to achieve policy ends by forcing other people to pay for Council's wishes. A better course would be to charge each new development for its projected runoff. In Victoria, a large condo project with zero run off was exempted from contributing to storm sewer development fees. This puts the onus on the developer to minimize his costs, which may include green roofs, or things like storm ponds, gray water recycling, storm sewer flow capacity regulators, green walls, waterless toilets, meadows, permeable pavements, green parking lots, etc.

And I would like such charges to apply to existing buildings as well. There is no good reason for an older building to be exempted from its environmental costs. I would rather the city decide the cost of dealing with rainwater runoff is $x per cu.meter and charge for the runoff from a site. If the householder or landlord can reduce his costs, they'll go for it.

I spent some time last summer looking at the cost of green roof planting trays, as I have two sections of flat roof on my home. Partly I want to aid water conservation and improve the urban air environment and reduce the heat island effect, but partly I want to reduce summer heat gain on my flat roofs, and by shading them, prolong the life of the roofing material, ie I am motivated. But I found the cost much higher than I expected, and its difficult to calculate the payback.

The key problem as I see it, is that Cities give away or fail to charge correctly for storm sewer capacity. I would rather the City itemize its costs, charge individual users accordingly, and let each homeowner and landlord use their imagination to come up with the most cost effective solution. But as long as sewer capacity is given away or charged arbitrarily based on some criteria other than useage, the sewers will be abused, green solutions will go unimplemented, and heavy-handled politicans will try to garner votes by forcing a select few into an ordained "solution" that is only superficially green.

1 comment:

  1. Eric - did you look into white roofing?