Expert Advice on Green Buildings

Green Roof Cost: What Is the Cost per Square Meter?

 
Question:

How much does a green roof cost per unit m*m for a residential building?

Answer:

Every green roof project is unique. The cost of a residential green roof depends on several variables including:

- Geographic location
- Thickness of the green roof
- Materials used
- Provider/installer (or green roof brand)
- Size of the green roof installation (economies of scale can be a factor in achieving discounts)
- Tax incentives in place (if any)

Certain countries, states and cities have economic incentives to encourage the installation of green roofs.

In the U.S., including the green roof membrane, which is considered to be the most expensive component of any green roof, depending on which state you are in, the cost for a green roof would range from $10 to $25 per square foot or $108 - $269 per square meter... (one square meter = approximately 10.76 square feet). More sophisticated green roof (or green wall) installations can cost from $25 to $100 per square foot, or $269-$1075 per square meter or more.

In New York City, the average green roof costs around $18-$20 per square foot installed. New York City green roof installations can receive a tax credit of $4.50 per square foot of green roof area or approximately 25 percent of the typical costs associated with the materials, labor, installation and design of the green roof. Building owners in New York City who install green roofs on at least 50 percent of available rooftop space can apply for a one-year property tax credit of up to $100,000. Building owners are able to apply for the credit starting Jan. 1, 2009. This is a pilot program that will expire after March 15, 2013, unless it is extended.

In Germany, the cost of a green roof is relatively low because the country has an economic incentives in place and an established green roof market.

Through economies of scale, cost reductions are common, however in a residential setting, there are two factors playing against you to attain a low cost:

1) Residential green roof installations are more expensive per square foot/meter than commercial installations because the fixed costs of the installation cannot be spread over a greater area.
2) The return on investment (ROI) associated with a residential green roof is harder to justify because the cost savings will often be lower than in a commercial setting.

As the roof of a building is critical to its safety and useful life, it is important to work with a reputable green roof manufacturer/installer.

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Expert Advice and Comments

It's also important to

It's also important to remember that green roofs also require some maintenance. Depending on the owners' objectives and the type of green roof, maintenance may be limited to weeding/removing unwanted seedlings and making sure the entire roof installation is healthy.

Calculations

A square meter is not a square foot times 3. Like a square yard, which is 9 square feet, a square meter is actually about 10.75 square feet, skewing your calculations horribly. Ironic then, that I need to solve a simple math question to post to this blog.

Conversion

Hey Anonymous, thanks for pointing out that error... much appreciated.

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