Build and Rebuild » Green Roofing

Three Types of Roof Garden

Megan — Fri, 11 Dec 2009 15:00:00 +0000

Roof gardens are built for both their aesthetic and their functional values. A roof garden can provide temperature control, architectural enhancement, hydrological benefits, and of course food. It can also serve as a habitat for wildlife. There are a number of advantages when you plant a roof garden. It can cool the room below it, especially during a hot day. During winter, it provides insulation against the cold. In Germany, roof gardens are required to retain water from evaporating. It will prevent flash floods from occurring. There are three basic types of roof garden. They differ according to the maintenance they require, the type of plants the roof will support and the depth of the soil. The three types of roof gardens are:

Extensive Roof Garden

This is the easiest type of roof garden to maintain because it uses shallow soil. Extensive roof gardens are lightweight, and ideal for the roofs on garages, sheds, and other small extensions of the home. Although it’s easy to maintain this type of roof garden, it has the least aesthetic value, and the number of plants that can grow on it is quite limited. Examples of plants you can grow in an extensive roof garden are lichens and mosses. Lichens are symbiotic organisms that can colonize on surfaces such as glass, metal and plastic. Mosses are small green plants that do not require large quantities of nutrients for survival. They cling on stone and walls and, can live off of rainwater alone.

Semi-extensive Roof Garden

This type of roof garden has deeper soil, and can support a larger variety of plants. It can therefore be decorated more easily than the extensive roof garden. The soil is heavier in a semi-extensive roof garden, and requires a stronger structure in order to support it. One could plant sedums in this type of garden. These are succulents that can store water in their tissues. That means you won’t need to go out and water them every day – but during times of drought, they could die and turn patchy if not properly cared for. On a semi-extensive roof garden, you can also plant wildflowers that can grow without any maintenance.

Intensive Roof Garden

This type of roof garden can support trees and elaborate arrangements. Intensive roof gardens require large, strong structures to support them. Most homes are not suitable for this type of roof garden, but they can be found on concrete buildings and on top of roof decks. There’s no limit to what you can plant in an intensive roof garden, so long as the structure of the building can support the weight.

Vegetation Blankets

Another interesting option for green roofing is the use of Vegetation Blankets. For more information, see Vegetation for Roof and Ground Covering. Image Source: http://www.flickr.com/photos/wengs/ / CC BY 2.0

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White Roofs?

Megan — Tue, 08 Dec 2009 17:59:14 +0000

You may have heard something about "white roofs" in the news but you may not know how they can help our planet, or a maintenance budget. I’ll try to clear things up a bit.

First, A few definitions, for the purpose of this article only.

a. White roof: A roof that is white in color and has a high rate of reflection of the sun’s energy.

b. Green roof: Any type of roof that will help our planet. Most white roofs are considered to be "green"

c. Planted roof: A roof that actually has plants growing on it.

d. Black roof: Old style roofs consisting of asphalt, rubber, or a combination of the two.

Most all of the commercial buildings in the world use black roofs. Because they are black, they soak up the sun’s energy like a sponge.

That’s bad for several reasons. Commercial roofs and pavement are the major factors in the "heat island effect" in major cities. Black roofs are typically almost twice the ambient air temperature on a hot day. Much of that heat is transferred into the building and places a tremendous load on the air conditioners, which use enormous amounts of electricity to keep the building comfortable. Black roofs have been around for decades because there were no alternatives.

White roofs. You might think you could just paint a black roof white and be done with it. Unfortunately, roofs expand and contract constantly. White paint will crack and leak almost immediately. We use acrylic elastomeric materials for our roofing systems. These materials will expand and contract up to 300%. They also reflect up to 85% of the sun’s energy, including UV. This virtually eliminates the heat island effect of that building, and will typically save up to 50% of the energy needed to cool the building. The energy savings with this type of roof are why energy czar Chu is traveling all over the world promoting white roofs. The total amount of energy savings potential is incredible, especially on a world wide basis. Upfront cost is comparable to a black roof, but a white roof will typically pay for itself in 4-7 years with energy savings alone.

Planted roofs are becoming more popular every day for several reasons. Many metropolitan areas in the US are having huge problems with excessive rain run off. A planted roof helps because it will soak up a great deal of moisture before it becomes saturated. In some cities, they are even growing vegetables on the roof. The major problems with a planted roof are cost and weight. A roof can only hold so much weight before it will collapse. Black roofs are quite heavy already so the ideal solution is to have a lightweight membrane underneath the plants to seal the roof. Flat roofs have always been hard to seal, having plants on top may preserve the covered portion of the roof, but there are almost always walking spaces for servicing equipment on the roof. Having to remove all the plants to service the actual roof surface would be very expensive, so we recommend a modern elastomeric membrane underneath so there will be no maintenance for many, many years. Planted roofs are beautiful, the plants produce oxygen, they reduce the heat island effect, and they save even more energy than a white roof, and they help tremendously with run off water. But, they must be done right in order not to leak.

White roofs, green roofs, and planted roofs may qualify for various tax credit programs which will help make them more attractive to building owners.

We can convert virtually any roof to a green roof. From the smallest Mom and Pop store, to the largest buildings on the planet, anywhere in the US.

If you own a building, or know some one who does, have them contact us to see what we can do. We only have one planet, let’s make sure our kids and grand-kids have a place to live.

Web site: White Roof Pros

Email: kwright@white-roof-pros.com

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Vegetation Blankets for Green Roofing and More

Megan — Wed, 25 Nov 2009 00:37:57 +0000

Vegetation blankets can be used to create green roofs, but they aren’t limited to just that.

A vegetation blanket consists of a layer of fiber covered in a substrate on which plant life can live; with various plant species growing on it.

These blankets can be used to cover roofs, roundabouts, sound barrier walls, and embankments – to name a few. They can literally be rolled up for transport and then unrolled on top of the surface you wish to cover.

Due to their flexibility, they are also versatile and can lie over a curved roof, a sloping surface, or just about any otherwise awkward area. They are light-weight, insulating, and low-maintenance.

What’s more, they are quite eco-friendly. A green roof can be used to absorb and evaporate water runoff that would otherwise be wasted – or even worse, that would flood sewer systems and pollute rivers (as is the case in Portland, Oregon, for example).

Furthermore, a roof which is covered in live vegetation absorbs carbon dioxide and emits oxygen, thus helping to restore balance on a carbon-heavy planet that currently needs all the vegetation and plant life we can put on it.

For more information on vegetation blankets, where to get them, related services, and other details, please see this product description of Sedum Vegetation Blankets.

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What color is your roof?

admin — Fri, 26 Jun 2009 04:11:54 +0000

According to a recent study, we can combat global warming just by painting our roofs white. The concept is simple. Rather than absorbing and transferring light energy into heat, white colored roofs increase the reflectivity of the roof’s surface keeping houses and urban environment cooler. According to the study, painting roofs white “reduces their solar heat gain, lowers their temperatures, and avoids transferring heat back into the atmosphere.” All of which reduces global warming.

California has been in on the research for quite a few years now. In 2005 they passed a law requiring all flat roofs to be white, and starting July 2009, they will require all sloped roofs to be at least “cool colored.” (Apparently, a state of white-roofed houses was just to much to bear aesthetically.)

Perhaps it isn’t revolutionary, but it is the little things that count. According to the study in Climatic Change, improving the reflectivity of urban roofs and pavements in warmer climates could offset up to 44 billion tonnes of emitted CO2, the equivalent of “600 million cars off the road for 18 years.” So I ask again: What color is your roof?

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