It's not just for hobbits anymore. The logic of green roofs is becoming more apparent. We can minimize our bills while maximizing the beauty of the urban landscape. And every day it's becoming a little easier to live in a house that just happens to have plants growing on it.
Vegetated roofs, or green roofs have a layer of living plants on top of the structure and the
waterproofing elements. There are really two types of green
roofs, intensive and extensive.
Intensive green roofs often have a soil depth of a foot or more, and
require substantial structural elements to support the weight of the
whole roof. Intensive roofs can sustain a wide range of plant species
and typically require a fair amount of regular maintenance. Because of
the additional demands they impose, intensive roofs are much less common
than extensive roofs.
Extensive roofs are much shallower, typically only 2 to 4 inches deep,
and are planted with particularly hardy plants. Over the last 50 years
or so, this kind of roof has been developed, especially in Europe,. But now they are becoming increasingly common in the United States.
Why are green roofs such a great idea?
First, they help to reduce roof
stormwater runoff. In some cases, this can help reduce the size of
stormwater pipes, and the amount of stormwater that needs to be
treated by municipal water treatment. In a light rainfall, a building
with a vegetated roof can have no stormwater runoff at all.
Green roofs also protect the roof membrane from sunlight, which breaks
down the roofing material. Having even a couple inches of soil helps
to greatly extend the buying levitra online canada life of http://spionline.com.au/online-cialis-cheap the roof, and a longer lifespan means less
material ends up in landfills from re-roofing buildings after the
membranes have failed.
Green roofs keep the roof cooler, which helps to reduce the
heat-island effect, which contributes to cities being hotter than the
surrounding countryside. This can be beneficial to the building in
reducing its summertime cooling load.
A green roof is also a source of oxygen and provides a habitat for some
birds. Birds and insects can find homes much more readily in the living
environment of a green roof, where an ordinary roof is nearly barren. And yes, it's even possible to price check 50mg viagra graze goats.
What is a green roof made of?
Starting from the top, an extensive green roof has a layer of plants,
which are typically sedums. These are low-growing, shallow rooting,
drought tolerant plants. There are many different varieties of sedum,
with different different coloration and different flowerings, so that a
roof can have a varied appearance, rather than looking like an entire
crop of a single variety. The plants are in a growth medium, an
engineered mixture of lightweight soils, vermiculite, and other
materials that provides a good environment for the sedum.
depth of the soil aids in keeping weeds from establishing themselves on
the roof, since most weeds cannot survive in the arid and shallow soil
conditions on a vegetated roof. Local plants that can survive in that
environment may establish themselves on the roof, as well. Underneath
the soil are several membrane layers, rather than just a single membrane
roof. There is also a drainage layer (to allow excess water to move
freely, rather than lifting the soil and best price viagra with prescription having it flow off the roof in
a mudslide, and a root barrier layer, which keeps the roots from
penetrating the order cheapest levitra online roof. The roof membrane sits on cheap buy viagra the roof deck,
insulation, or structure of the building much like a conventional roof.
Can I put a green roof on my house?
Green roofs make sense for residential use as much as for commercial
buildings. However, retrofitting a green roof onto an existing house is not a
simple matter because of http://plaisirdecreer.be/get-viagra-fast the extra weight a vegetated roof adds. Most
roofs are not structurally strong enough to support a vegetated roof
without some reinforcement. Green roofs also work best on lower slopes.
They can be installed on steeper pitched roofs, but the design and
installation is more difficult and requires additional care.
The added cost of a vegetated roof versus a conventional shingle roof,
and the relatively small number of contractors familiar with installing
them are probably the biggest limiting factors. A house with a suitably
pitched roof would still likely need structural evaluation from an
architect or engineer before going ahead with a retrofit, and some
structural reinforcement is likely to be needed.
What Does the Future Hold?
Does a green roof have to be mowed?
A sedum covered roof is naturally self limiting in size. Most sedums
grow only a few inches tall. As mentioned above, it is also fairly self
weeding, due to the inhospitable environment it offers to most weed
species. An extensive roof planted with prairie grasses on the Ducks
Unlimited National Headquarters in Winnipeg, Manitoba uses a controlled
burn of its upper roof every three years to viagra propranodol repropogate the prairie
plants. The 16 inches of soil protects the building from any damage
while the grass fire helps remove weed species and assists prairie
species which need periodic fires as part of their life cycle.
We were excited a while back to announce Toyota's green roofing tile. These modular, interlockable grass tiles make green roofing an absolute cinch.They're a lot lighter than other methods, and installation is a breeze. At about $34 per tile, they're still expensive, but prices would of course drop if demand were to increase.
And, second, I and many others would like to see Friedenreich Hundertwasser's vision of every horizontal surface being returned to nature:
The true proportions in this world are the viagra no presciption views to the stars and the
views down to the surface of the earth. Grass and vegetation in the
city should grow on all horizontal spaces - that is to say, wherever
rain and snow falls vegetation should grow, on the roads and on the
roofs. The horizontal is the domain of propecia mexico nature and follow link cialis india pharmacy wherever vegetation
grows on click now generic cialis without prescription the horizontal level man is off limits; he should not
interfere. I mean taking away territories from nature, which human
beings have always done.
1. Hundertwasser's Waldspirale, Austria...From WikiMedia Commons
2. Green Rooftops from Swishphotos on Flickr
from the Faroe Islands
3. Grass Roof in Oswego Illinois, USA, from Greg Robbins on Flickr
4. Solaire Green Roof in Battery Park City, NY from Birdw0rks on Flickr
5. Goats on a Roof in Wisconsin, from Driftless Media on Flickr
6. Grass Roofs in Iceland from Pietroizzo on Flickr
7. Green Roof in Tokyo from Dissonanc3 on Flickr
8. Toyota Roof Tiles from Toyota Roof Garden
9. Hunderwasser's village model, on display at Kunsthaus in Vienna