Have you ever seen a gorgeous green roofing system? They’ve been very popular in commercial settings, but recently they’ve spilled into the residential roofing market. Thanks to their growing popularity and the increasing number of vendors, these living roof systems become more and more accessible each year. So how does one go about building one of these green roof systems? Here’s a quick guide on the subject!
What is a Green Roof?
While there are multiple varieties of “green roofing” we’ll focus on the literal category. These living roof designs utilize natural plant life, situated within a special growing medium atop a waterproof layer. These plants grow and multiply just like any other, although measures are taken to prevent roots from penetrating underlying layers. The result is a beautiful, energy-efficient roofing system that benefits the environment as much as your home or business.
Green Roof Benefits
There are numerous benefits to owning a green roof system. Below are just some of the many perks homeowners enjoy:
- Plants create an environmentally friendly environment.
- They also purify the surrounding air.
- Green roof systems boast a high energy efficiency factor.
- Local government sometimes offers tax incentives.
- The roofing is visually striking.
- Green roofing systems are low-maintenance.
- The growth medium absorbs up to 70% of water when it rains.
- You don’t have to worry about hail dinging your roof.
- The roofing absorbs sound from outside.
- Green roofs tend to increase the value of a property.
As you can see, there are plenty of reasons to choose green roofing for your home. There are some important questions to answer though, before getting into the planning process.
How Much Does a Green Roof Cost?
First, it’s worth noting that there are two kinds of living roof: extensive and intensive. Extensive systems utilizes smaller plants and requires less growth medium as a result. The starting cost lies at $10 per square foot of roofing. Intensive green roof systems can support larger plants (even trees), so in needs a deeper reserve of growth medium. Starting costs per square foot is $25 for these roofs. You can also expect yearly maintenance costs to run anywhere from 75 cents to $1.50 per square foot.
Do Green Roofs Leak?
One of the great perks of green roof systems is that they (the plants and growth medium) absorb up to 70% of rain water. These systems are designed with a special drainage system that directs extra water away from the roof. Roofs are generally checked for leaks during installation, and they have a waterproof membrane installed beneath just like any other roofing system.
That being said, it is possible for green roof systems to develop a leak. When that happens, you can talk with your green roofing specialist about inspecting your roof and fixing the damaged area. There are also specialized equipment that can locate the area quickly without destructive digging. Though it might not be as demanding as your plumbing maintenance, green roofing upkeep may include the occasional watering of plants during extended dry periods and minor sectional replacement if any plants die.
How to Design a Green Roof
Choosing a Size
First of all, you’ll need to weigh your options based on roof support requirements, budgeting, and functional goals. Remember, the more growth medium installed, the more weight support required. Even if you are installing a smaller green roof section, you’ll need to talk with your roofer about building sufficient supports.
Most homeowners with a smaller base roofing system choose an extensive roofing system with the lower growth medium volume. Large homes and businesses may choose a intensive solution, so that they can enjoy a rooftop garden environment. It’s important that you choose the solution that’s right for your property size.
Choosing Your Roof Plants
Your local green roofing company’s input is particularly valuable in this planning phase. You’ll want to pick flora that specifically thrives in your home’s local environment. That includes yearly and seasonal rainfall, the amount of direct sunlight your roof will experience, as well as any exhaust coming out of your home. For areas that have long periods without rain, drought tolerance is a must for your plants.
Now you can have plants put in during installation, or you can choose a pre-grown plant mat. Plant mats come matured shrubs without any weeds inside. These mats are simply rolled out onto your green roof section by section after the base layers have been installed.
Living Roof Construction
The Installation Process
First, a special boundary is constructed to hold back the plant growth and the growth medium. If you’re wondering which materials work best for this structure, you’ll want a water-friendly, corrosion-resistant material. Many professionals recommend a rot-resistant wood. In the boundary, drainage holes should be cut into the sides to allow water to drain (though these should have a screen to prevent medium from falling out.
Second, a waterproofing layer is installed on top of your existing roofing system. Your current roof structure doesn’t go away. In fact, it still provides a key insulating layer and roof supports to manage the weight of the plants and earth.
Third, a drainage layer is placed that will capture and direct any water that slips through the growth medium. Careful design is absolutely essential in the section, in order to avoid pooling water beneath the plants. There’s a bit more to the drainage system that we’ll touch on in a second.
Lastly, a root blocking cloth is installed to prevent plants from extending beneath the growth medium. This layer also allows water to pass through into the reservoirs below. On top of this layer is the growth medium itself and the plants therein.
Why You Should Trust a Professional
While some of the work could easily be completed by a savvy homeowner, green roofing systems should be installed by professionals. Installing the root barrier, lifting the materials, and other aspects of the process all benefit from a trained experts touch. Other perks of using a professional include:
- It’s safer when constructing the structural supports.
- Better design and implementation for your drainage system
- There are fewer chances of leaks in the waterproof layer.
- You’ll learn which plants work best with your local environment.
- Overall installation will be completed faster.
Our team at Prusak Construction & Roofing, Inc. would love to help you design and install a green roof for your home! To learn more about living roofs, optimal roof plants, or any related topic, talk with our experts about green roof systems in Bridgeview and Chicago, IL by calling (708) 422-2624.