Busted, 6 Green-Roof Myths

Green roofs, living roofs, vegetated roofs, ecoroofs — whatever you want to phone them, they’re sprouting up everywhere lately, including atop residential homes. With that growth in popularity stems overall assumptions and misconceptions. As an instance, that green roofs are just for ecobuffs, they’re high maintenance and they’re experimental and risky. All untrue.

Let’s look at some common green-roof myths and see whether they, er, hold any water.

Baldridge Architects

The Basics

A green roof is one which fosters the development of vegetation. It’s created from a waterproofing coating, a root barrier, a drainage system and growing medium for the plants. “Intensive” green roofs, or roof gardens, could be available and can comprise considerably bigger plants and even water features.

Prentiss Balance Wickline Architects

An “extensive” green roof, on the other hand, is a thinner, lighter, version which looks much like a typical roof. It may be sloped or flat. Often it will be planted with sedum (stonecrop). Most “semi-intensive” green roofs are home to various plant species, such as native grasses and blossoms.

Mariana Pickering (Emu Building Science)

Common Myths

Myth No. 1: Green roofs are a new and experimental portion of the green trend.

When do you think the residential green roof in this photo was installed? Five years back? Ten? Maybe 20? This green roof has been protecting this German house because the 1940s — more than 70 years back!

Last May I had been able to attend the International Green Roof Association’s convention in Hamburg, Germany. Included in the conference program, we visited the little community of Wohldorf-Ohlstedt. This roofing and others like it had been assembled in 1943 in one of three Norwegian settlements. The area has been intended to be a social housing alternative for the needy, for example former concentration camp prisoners. It later became a middle-class suburb, with the green-roofed houses getting very sought after but seldom available.

Green roofs have existed for centuries. It is the execution of these that is becoming more technical of late, allowing for lighter and thinner roof profiles.

BRIBURN — Architecture for Life

Myth No. 2: A green roof is just for a green building.

Certainly there are lots of green construction certifications that award points for your installation of a green roof. The environmental benefits are undeniable. However, even homes which don’t have a specific eco objective may gain from the aesthetic and economic aspects of having an elongated garden space.

DeForest Architects

Who would not want to check at vibrant green instead of bland shingles from their window?

Christian Duvernois Landscape/Studio

Or maybe you’re just looking for a way to gain some much-needed outdoor space in an extremely dense urban atmosphere.

Mariana Pickering (Emu Building Science)

Green roofs can save you money, also. Back in Germany (where green-roof research has the longest history), extensive green roofs function as an economical alternative to other options. They’ve been shown to reduce heating and cooling costs, reduce stormwater runoff (and consequently flooding), and supply added commercial space, which subsequently raises the market value of a property.

The advantages of stormwater mitigation have been noticed by the city of Portland, which now runs on the Portland Ecoroof Program, providing incentives to developers who look vegetated roofing systems.

Narofsky Architecture + ways2design

Myth No. 3: Green roofs may look fine, but they can cause structural issues and leakage.

This is maybe one of the most cited concerns of customers. Allow me to be clear: A leaky roof is different from whether it is a green roof or a conventional roof. It’s to do with the installation and design specification of the construction. All roofs should have a suitable waterproofing system, green roofs comprised.

Coburn Development

There is no evidence to indicate that green roofs are more prone to leaking. Actually, some studies indicate that the longer life cycle of a green roof is a result of the security of the watertight membrane from ultraviolet sunlight. The plants and substrate act as a natural barrier to weathering.

Website lines architecture inc..

A correctly engineered green roof may also have a root barrier to prevent plants from trying to root overly deep.

This homeowner chosen to get his vegetable garden on the roof (possibly to keep it protected from hungry animals).

Jeffrey Gordon Smith Landscape Architecture

Sometimes a green roof design can specify a gravel border around the edge of the roof to keep plants away from your more intense weather and wind conditions at the edges of the roof. Nonetheless, this isn’t always necessary; it depends greatly on the sort of green roof and the plants. Each these factors are taken into consideration once the architect and green-roof professional layout the machine.

Jeffrey Gordon Smith Landscape Architecture

Newly constructed homes must meet the demands of the engineered loads, therefore provided your contractor and structural engineer are on the same page about your desires for a green roof, there should be no issue for a new home to meet the structural requirements.

For retrofitted green roofs, you need to be somewhat careful. Requirements will depend a lot on which portion of the country you reside in and what kinds of loads your home was originally supposed to sustain (snow, wind, rain etc.).

Green Roofs of Colorado

Myth No. 4: Green roofs are costly and difficult to irrigate.

A lot of men and women think that a green roof has to be planted with sedum or other succulents as it is impossible or prohibitively costly to irrigate a green roof. The reality is that all of green roofs require irrigation in the beginning while the origins of the plants are establishing themselves (with the exception of pregrown mats made offsite). The reason that water-storing plants are popular is since they’re beautiful and hardy enough to stand up to the tough requirements of a roofing.

However, occasionally combining these with other kinds of vegetation, such as native grasses, may be a fantastic way to introduce additional diversity and increase the aesthetic allure of the roofing. Intensive roofs, or roof gardenswould be the ideal illustration of this. Some even have bushes and trees.

Casey Boyter Gardens

The irrigation demands of a green roof are specific not only to plant selection, but also to the local climate. I recently talked with Casey Boyter of Casey Boyter Gardens in Austin, Texas, about how to look green roofs to the long, hot, Texas summers, in which occasionally temperatures stay over 100 degrees Fahrenheit all summer long.

She pointed out that if it eventually does rain, it rains a lot. Thus it isn’t just important to select drought-tolerant plants that may make it through the heat waves, but it’s also necessary to design a thicker substrate (growing medium), manufactured from materials that can absorb considerable quantities of water. The drainage layer may also have deep pockets inside (similar to an egg carton) to store water which will then be discharged back to the plants throughout the next heat wave.

Casey Boyter Gardens

The demand for irrigation is cut down substantially with these features. Actually, lots of green roofs require no additional water once they are established. They become an integral part of nature’s water cycle for that particular site.

“When we begin to consider each site as self-regenerative and consider closed-loop bicycles for our water, I assure you we would be further away from the increasing desertification of our landscapes,” Boyter says. “Green roofs, dwelling architectural systems, are a tool to boost the quality of their own lives as well.”

The Watershed Company

Mark Garff at The Watershed Company in Seattle has a similar strategy. The roof gardens in this photo were specifically designed to entice insects, particularly pollinators like bees, ” he says. “We made additional planting depth to increase species diversity,” he says.

This means that a green roof can act as an extension of the natural landscape on and about the site. The roof becomes a part of a healthful and balanced microecosystem, supporting biodiversity.

“long-term irrigation of a green roof is no more expensive than any other planting area,” he says. To offset the costs, the irrigation water could be chosen as rainwater, as is the case for your green roof in this photo.

Moss Yaw Design studio

Myth No. 5: You can just place some dirt on your roof to create your own green roof.

Stop! Do not do it. A well-designed green roof is made from much more than good potting soil. Often it does not even include things like soil, but rather calls for perlite or other porous lightweight stuff.

As I mentioned before, the construction of your home needs to be examined to see whether it could handle the load of a rain-soaked green roof. The particular climate of your site will need to be thought about, and plant selection and drainage systems will need to be designed.

Spore Design

This does not mean that all green-roof programs need to be built in, nevertheless. Some professionals in North America are using modular systems in their own design specifications. By way of instance, Aaron Kang-Crosby at Spore Design says the company employed a modular method by LiveRoof with this particular roof deck, with sedum already developed in from a local nursery.

(I personally have not seen these systems utilized in Europe, and I’m interested to hear what readers have to say about their functionality.)

Casey Boyter Gardens

Myth No. 6: A green roof is simply too pricey and complicated.

It sounds a lot of people are intimidated by green roofs because they do not know where to begin or how much it will cost them.

“Selecting the right team of professionals is one way to maintain both short-term and long-term prices down,” Boyter says. You may begin with asking your architect or assessing the database of licensed green-roof professionals in your area.

DANIEL HUNTER AIA Hunter architecture ltd..

The Environmental Protection Agency estimates that the cost of a green roof at $10 to $25 per square foot. Obviously, this price is extremely variable, depending on whether you want an inaccessible sedum roof or an available roof garden.

The warranties on the construction products used in a green roof are similar to those for all the other construction products in a home. They need to be set up according to the manufacturer’s specifications with a skilled professional.

Casey Boyter Gardens

Each green roof setup should come with a service contract to deal with annual maintenance. The extent of that care will depend a lot on the way you want to use your green roof.

According to Boyter, the care program ought to be a part of the first design and setup, with a two-year and also a five-year plan comprised, or maybe an even longer plan in certain conditions.

The life spans of residential green roofs are still mostly undocumented, but some professionals say that they may be double the lifespan of a conventional roof. The green roofs of Rockefeller Center in nyc, by way of instance, possess the same waterproofing membranes which were set up in the 1930s.

Do you have a green roof on your house? Please add a photo in the Comments.

More: Watch additional benefits and other designs for living roofs

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