Green Roof Installation Cost

by Mr. RoofingJanuary 8, 2020
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How Much Does It Cost to Install a Green Roof?

Known as living roofs, green roofs, and green roofs, green roofs offer many benefits to the user. The process of growing live plants on the roof of a home or building has been shown to dramatically reduce building cooling costs while improving stormwater management and air quality in the area.

There are several types of green roofs, which leads to a wide range of associated costs. Average homeowner creating sprawling 1,500 square foot green roof. ceiling, you can expect to spend between $ 15,000 and $ 30,000, with most paying around $ 22,000 for the project.

Green Roof Costs Per Square Foot

Most people consider three basic types of green roofs, along with two subsets that can be used in special cases. For residential purposes, only expansive ceilings are an option, unless installed in a multi-residential building.

Green Roof Installation Cost

Extensive roof
A large green roof is the most common and least expensive type of green roof, with costs ranging from $ 10 to $ 20 per square foot 2. They consist of a thin layer of soil, with a continuous cover of growing material. They are quite light and can be installed on roofs with an inclination of 0º to 30º. They are virtually maintenance free once installed and require no watering.

Semi-intensive roof
A semi-intensive roof is often called a roof garden. It is heavier than a sprawling roof and generally has plants in modular containers rather than growing freely. When built on a concrete roof, visitors can walk around the growing medium. Costs start at $ 15 per square foot 2 and range around $ 30 per square foot 2. They require more care and maintenance, as well as irrigation, but can provide a more sculpted appearance.

Intensive roof
Intensive roofs are very heavy, with a thick layer of soil. They allow the most customization for the roof, but are the most expensive, with costs ranging from $ 25 to $ 35 per square foot 2. They must be installed on a flat concrete roof and require a lot of care and maintenance, as well as watering. These are not normally practical for residential buildings, but they can produce extremely dramatic and beautiful results.

Teal roof
The greenish blue roof is designed for urban use in areas that receive very heavy rainfall and need rain storage and management. They combine rain storage techniques with green roof technology, so they have fewer plant options. They require a flat concrete roof that can support the weight. They cost between $ 25 and $ 35 per square foot 2.

Bisolar roof
A bio-solar roof is a green roof that has solar panels installed. It can be intensive or semi-intensive and generally has modular growing media rather than full coverage. The green roof portion costs $ 25- $ 35 per square foot 2, and the solar panels cost an additional $ 18,000- $ 20,000. They are not normally installed on residential roofs due to weight.

Green roof plot

The pitch of your roof dictates, in part, what type of green roof system you can use and whether you can install a green roof system. Intensive green roofs must be installed on concrete roofs with a 0º slope. Extensive green roofs can be installed on roofs with an inclination of up to 30º but preferably less than 20º. The flatter the roof, the easier it will be to install the growing medium and plants.

Modular vs integrated green roof system

Depending on the type of green roof you choose and the pitch and material of your roof deck, you may be able to have a modular or built-in 3 system. Modular systems involve the use of plants in trays, so you can better customize the appearance of the roof and create walking paths. However, the trays tend to be heavier and are reserved for commercial buildings with concrete roofs and intensive systems. Extensive ceilings are generally integrated 1 with full coverage because they are lighter and can be installed on a variety of roofs, including those with moderate pitches and standard 4 plywood decks.

Green roof tray system cost

Tray systems are used for extensive and semi-intensive roofing, and have a thin layer of soil or planting material contained within the system. The tray acts as a barrier between the plants and the structure underneath, preventing any overgrowth, protecting the roof, and keeping the plants safe and locked together in a closed system. Costs for a green roof tray system range from $ 10 to $ 30 per square foot.

Labor costs to install a green roof

Labor makes up a significant part of the cost of a green roof, primarily because the process of creating one can be labor intensive. Laying the materials on the roof, constructing the layers, and installing the plants are time consuming and can cost $ 5 to $ 10 per square foot 2 in labor.

Roofs with a steeper slope or with very intricate growth patterns cost significantly more than roofs that have seeds mixed into the growing medium prior to installation. For 1,500 square feet. ceiling, expect the labor share to account for about $ 10,500 of the $ 22,000 total.

Green roof installation process

Green roofs are essentially built or installed in layers. Every installation should begin with an evaluation by a structural engineer to determine how much the roof can hold per foot 2. Not all roofs are good candidates, and some roofs require substantial work before installing a green roof.

A roof barrier, which is generally a heavy plastic type, is stretched over the roof to ensure that roots do not penetrate the roof deck. If the roof has walls or if there will be walking paths, these are lined with some type of gravel. Then the moisture retention layer is put on, which looks like an egg box. A filter cloth goes on top of this, which is what the substrate or soil will retain.

The soil is laid on the filter cloth and then the plants are installed. This can be done through seeds, planting seedlings and small plants, or installing trays of already grown plant material. Installation takes about 5 to 7 days, but the plants will take several weeks to establish.

Green roof plants

The plants for a green roof vary, depending on the area where you live and your climate. Like ground-growing plants, your green roof plants do best if they grow well in your climate. Wildflowers and sedum work best, but you can also plant grasses and a variety of other plants. Some of the best options include herbs, clover, groundcover, and succulents. For a sprawling green roof, the plants must be able to grow in less than 5 inches of soil. Plants for an intensive green roof can have a deeper root system.

Green roof irrigation system

Extensive green roofs, most often used for residential homes, do not require watering. However, semi-intensive and intensive roofs do. In most cases, an irrigation system 5 designed on the roof itself is needed, both for drainage and to allow adequate irrigation and distribution so that all plants receive the correct amount of water. Also, you don’t want large puddles of water. This can be done through tubes and also by using mats to store water.

It is also important to note that many green roofs depend on plants like succulents because they store water and do not require as much irrigation. So natural rain may be all that is needed.

Benefits of a green roof

Green roofs have numerous benefits for the user. They have been shown to reduce building cooling costs by up to 25%. They also help manage stormwater runoff in areas with high rainfall and can improve air quality when installed in urban settings or on large city-wide scales.

Green roofs are also attractive and some may require very little maintenance, extending the life of the roof. However, the costs of installing a green roof are high. They are expensive and the most intensive green roofs can only be created on concrete roofs that can support their extreme weight.

While many people like the idea of ​​a rooftop garden, it is not easy or possible to achieve in most residential settings. In the winter months, a green or living roof may not look as attractive because the plants may not be evergreen. Intensive green roofs installed in commercial buildings also require a lot of maintenance and irrigation to help them stay as well as possible.

Green Roof Maintenance Costs

The amount of maintenance your green roof requires has a lot to do with the type of roof and the plants you install. A large roof that is well established does not require a lot of ongoing maintenance. You may want to fertilize it occasionally or water it in times of drought. Otherwise, the sprawling roofs are relatively self-supporting. For a large roof, expect to pay $ 0.75 to $ 1 per square foot in maintenance costs each year.

Intensive roofs, however, need more work. If you have a roof garden, it may require the same level of care as any decorative garden bed. You should also water regularly and check that the drainage systems are working properly. Your roof should be inspected regularly to make sure it is supporting the weight of the green roof properly without moisture problems or leaks. For an intensive roof, annual maintenance costs range from $ 1 to $ 1.50 per square foot.

Cost of Green Roof vs Conventional Roof

When comparing the costs of green roofs and conventional roofs, it is important to consider both short-term and long-term costs. In the short term, green roofs are more expensive than conventional roofs because installation and material costs are higher overall.

However, in the long run, having a green roof can save you money compared to a conventional roof. A green roof provides insulation to the home, reducing energy needs and therefore reducing the amount of money you spend on utility bills throughout the year.

Not only that, but a green roof also protects your roof structure from things like sun, rain, and snow, extending the life of your roof and minimizing the number of repairs that need to be done. Overall maintenance costs are also lower for green roofs than conventional roofs, and studies have shown that green roofs can save home and building owners thousands of dollars in the long run compared to conventional roofs.

Enhancements and Improvements

Roof inspection

Unless you have a new roof installed to support a green roof, your existing roof should be inspected prior to installation. Roof inspections cost between $ 50 and $ 500, depending on the size and level 6 of the inspection.

Additional Costs and Considerations

  • Some locations require green roof permits, while others have ordinances prohibiting them. Check with your city or council for more information.
  • You can put a green roof on an existing roof or building, but it needs to be inspected first to make sure it can support the weight.
  • Green roofs can include plants with many shades and shades that grow on them. They complement a wide range of house colors, but work particularly well with any “natural” or nature-inspired color palette, including grays, creams, tans, and some shades of green.
  • Green roofs have been around for centuries. But they have only gained popularity lately for their benefits and the fact that it is possible to have thinner and lighter roofs, making them more accessible.
  • Most homes can benefit from a green roof, whether it’s green building certification to the aesthetics of a rooftop garden.
  • Green roofs are not known to leak, and some people think they last longer because the plants protect the membrane from UV light.
  • Seed and planted green roofs tend to work better in the long run than modular green roofs.
  • Some areas may have incentive programs that offset costs. However, many green roofs pay for themselves in the long run with lower energy costs.

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