Green Roofing: Frequently Asked Questions

At a time when more companies than ever are going green, the environmental design industry is expanding rapidly. Today, companies embrace practices that benefit their finances and the environment simultaneously, such as eco friendly roofing. If you have heard of green roofs (a.k.a. natural and eco friendly roofs), but are unacquainted with their construction and benefits, the answers below can help.

How are green rooftops constructed? Natural roofs are constructed of the following elements: a high quality waterproofing membrane, a roof deck, a drainage and irrigation system, soil areas, and shallow growing plant life. These elements combine to form a rooftop that offers numerous environmental and financial benefits.

Are green rooftops different than rooftop gardens? Natural rooftops are superior due to their design. A rooftop garden is essentially a garden on a rooftop, which brings the following disadvantages: the need for increased structural support, lack of proper waterproofing, lack of proper decking, lack of proper drainage and constant maintenance. Conversely, green roofs are designed to eliminate these problems, and feature a high degree of self-sustenance.

Is it possible to grow trees on a roof? Trees with shallow root systems may be acceptable on certain rooftops, but larger trees would require too much soil.

Do eco friendly roofs improve energy efficiency? Natural rooftops can improve energy efficiency in the following ways: by deterring heat escape in the winter, deterring heat intrusion in the summer and increasing HVAC efficiency. Research by the National Research Council of Canada (NRC) shows that natural roofing can reduce the demand for summertime air conditioning by up to 75%.

How do green rooftops benefit the environment? Natural roofing benefits the environment in critical ways. For one, it improves air quality by capturing airborne pollutants and atmospheric deposits. For another, it improves the cleanliness of storm water runoff by up to 85%. It also improves roof longevity, decreasing landfill use.

Do natural rooftops last longer than standard ones? A natural roof can improve upon the life cycle of a standard one-meaning one that could deteriorate within two decades-by up to 100%. Although it costs more initially, an eco friendly rooftop is the most affordable option in the long run, both in terms of repair and replacement.

How much does a natural rooftop cost to implement? Cost of implementation is based on the following factors, among others: a roof’s square footage, how easy it is to access, the types of plants chosen and the cost of construction supplies. To find out how much green roofing would cost for your building, contact a roofing company that specializes in eco friendly designs.

Can an eco friendly rooftop be placed on a pitched roof? Technically, an eco friendly rooftop can be placed on almost any style of roof, including one that is pitched. However, pitched roofs only accommodate shallow growing grasses, vines, and flowers, and may not feature the same design benefits as their flat counterparts, which are the type of eco friendly roofs that most commercial roofing contractors in the U.S. specialize in.

Roof Gardens: Green and Brown Roofs – The Differences and Benefits

Living roofs are soaring in popularity, both in residential and commercial projects, due not only to their aesthetics, but also the many environmental benefits they bring to the building. You will note if you visit horticultural events such as Chelsea or Hampton Court Flower Shows that many of the show gardens incorporate green roofs in some way, which is always a good indication of future trends. Here is a brief guide, explaining firstly what green roofs and brown roofs are, before detailing their uses and benefits.

Green Roofs

Green Roofs are basically roofs which incorporate planting, often sedum or wildflower and meadow planting, grasses and mosses. In fact, some can even be planted with trees and shrubs. The Roof Gardens in Kensington is a prime example of this. Installing a green roof creates a vegetated surface which provides colour and interest throughout the year. Often, living roofs are used in rural settings and in areas where the buildings need to blend into the background. Green roofs will either be planted or seeded.

There are of course many considerations before installing a green roof, primarily ensuring your roof is suitable, and ensuring it is completely watertight. It is always recommended to get a professional company carry out the work, as you could do more harm than good if not done properly.

Of course, living roofs/wildflower and meadow roofs create a dramatic visual impact, but they also have many other benefits.

Benefits of Green Roofs

1. Photosynthesis – the process of plants absorbing carbon dioxide and releasing oxygen. This is of particular benefit in urban areas.

2. Filter pollutants and dust from the surrounding area, again, a huge benefit in urban areas.

3. Green or living roofs act as an insulating layer on your roof. You should therefore expect to spend less on your energy bills, thus reducing your carbon footprint.

4. Increase in biodiversity – encourage animals such as bees, butterflies and birds into the area. With the current bee crisis, any opportunity to encourage bees into the area is a huge benefit.

5. Living roofs can be fitted with bird boxes to encourage birds, often endangered species, into the area and give them a safe environment to nest.

6. Endangered plants can be introduced into the roof planting.

7. Green roofs can reduce stormwater runoff significantly, which can help alleviate flooding, another very topical issue.

8. Often used as social areas, perhaps on top of office buildings, allowing staff to have somewhere green to escape to in the middle of an urban area. They are also increasingly being installed in public areas, to provide much needed green space in built up areas. A good example of this is on London’s Cannon Street Station.

Brown Roofs

Brown roofs are very similar to green roofs. The main difference is that whilst green roofs are often installed partly for the aesthetic value, brown roofs tend to be installed for environmental reasons, mainly, to encourage plants and wildlife.

Brown roofs are generally made using recycled materials and local soil. Whereas green roofs are often planted using very specific plants and following structured plans, brown roofs evolve more naturally. Whilst they are called brown roofs as this is the colour they are at the time of installation, they generally turn green over a period of time once the plants have started to establish themselves.

Brown roofs can incorporate water pools, wetland areas, rocks and boulders, basically any materials which will attract wildlife.

Benefits of Brown Roofs

1. Encourages wildlife into the area – brown roofs are specifically designed with this in mind. Particular plants may be introduced with the sole aim of encourages bees or butterflies. Wetland areas will encourage other types of insects and animals.

2. Brown roofs utilise soil and rubble which has been left behind after construction work. This ensures that wildlife which may have been displaced when construction work began, are encouraged back into the area.

3. As with green roofs, air quality is improved, which is particularly beneficial in inner city areas.

4. As brown roofs are made using recycled materials, they are the greener alternative.

5. Brown roofs generally have all the benefits of a green roof. They may take slightly longer to develop and flourish, but the environmental benefits will more than make up for that.

We in the UK are in some ways falling behind other countries with regards to green and living roofs. This has now been recognised, and a policy has now been written up to introduce more of this type of roof to both new and existing buildings wherever possible.

Low Sloped Roofing: Frequently Asked Questions

Roofs that appear flat often contain a low slope. For example, “flat” commercial roofing can be sloped nearly two degrees-a measure that brings significant benefits. Flat roofing that contains a slope lasts longer and is easier to maintain, two qualities that any building owner wants in a roof. If you are considering implementing a low slope roof, but have questions about its efficacy, the answers below can help.

Why is a slightly angled roof better than a flat one? Flat roofs allow pools of water to collect above sagging roof decking. As roofs age, these pools can gradually seep through their coating and water barrier, causing leaks and water damage. In cold weather, standing water can form ice dams that prevent water from draining, resulting in pressure that could cause decking to sag or collapse.

How much does a low sloped roof cost compared to other designs? The cost of a rooftop is based on three factors: surface area, materials used and labor required. With that said, flat roofs, which require fewer materials and less construction than pitched roofs, are quite affordable new. But replacing them can cost more than replacing pitched roofs, which may require only felt underlayment and shingles or tiles.

How many types of low slope roofs are available? Some companies offer up to six types of roofing technologies for “flat” roofs: energy efficient thermoplastic polyolefin (TPO), ethylene propylene diene terpolymer (EDPM) that is applied in an adhesive sheet, vinyl single-plys, hot mopped tar roofing covered with gravel, modified rubber bitumen roofing, and rolled roofing that has a mineral surface. Some of these solutions work better for some buildings than others.

Can a slightly angled rooftop be used as a green rooftop? As they have their own design elements, green roofs are not simply placed on an existing rooftop. While they do require a rooftop that is basically flat, their support requirements extend deeper than roof pitch. Garden rooftops should be pursued for their own merits, not simply as an aesthetic addition to a flat roof.

How much maintenance do low sloped rooftops require? With the best materials in place, maintenance inspections may occur twice annually. For example, a high quality ventilation system, drain guards and topcoat should be in place if inspections are conducted twice annually. Under standard conditions, light commercial roof repair and maintenance are performed thrice yearly.

What are the Disadvantages of a low sloped rooftop? Ice damming, high replacement cost, leaks, increased interior heating in the summer and frequent maintenance are disadvantages associated with low sloped roofing. However, these problems can be reduced or eliminated with the application of the right materials and design techniques.

Is it possible to keep repairing a flat rooftop instead of replacing it? When the right materials are used and proper maintenance is performed, repairs can preserve a flat rooftop for an extended period of time. As designs go, garden and concrete rooftops tend to age the best, with the former improving a roof’s lifespan by up to 100%.