If you like landscaping and take care of the environment, then it is a great idea to create more greenery on the site, turning a regular roof into the green one. This is especially true for urban dwellings, where space for gardens is limited. Your home will stand out from other homes and will reduce greenhouse gas emissions and its environmental impacts. We will discuss the impact of a green roof on the energy efficiency of a house below.
What is a Green Roof?
The green roof also referred to as a living roof, is a conventional roof that has been enhanced with a waterproof membrane, a drainage system, and a growing medium that is then covered in vegetation.
The difference between green roofs and other rooftop gardens is that they are usually not planned as accessible to the public. Green roofs are suitable for many applications, including distribution centers, business and office buildings, public buildings and even private roofs. Green roofs also differ in that they add from 17 (dry) to 30 (wet) pounds per square foot to a roof load on the roof, while roof gardens can add up to 100 pounds per square foot or more.
In addition to the main function of the roof, these moderately light loads reduce development costs, while providing huge environmental, aesthetic, and social benefits.
In urban areas, the standard roof includes a dark top, tar and shake. This captures a lot of heat that makes metropolitan areas more stuffy than their suburbs. This is called the urban heat island effect. I addition, getting heat requires a lot of energy and water. Using green roofs can quickly reduce this effect.
Green Roof Benefits
Green roofs covered with plants and vegetation give many advantages to the building. Here are the main benefits of green roofs:
- Insulate the home by keeping both the heat in and cold out: control the cooling temperature in summer and reduce heating bills in winter by 10 percent.
- Absorb up to 80 percent of stormwater runoff.
- Extend an average roof lifespan (from 15 to 50 years).
- Reverse the effects of urban heat islands by absorbing heat.
- Provide habitat for urban-dwelling animals and insects (bees).
- Significantly improve urban design and recreation space.
- Some cities offer grants or incentives for green roof construction.
- Improve air quality by reducing harmful gases (sulfur dioxide and nitrogen oxide).
- Create the best conditions to maintain solar panels for the best efficiency by keeping a suitable temperature.
- Increase the value of real estate.
The Main Types of Green Roofs
Now you understand the great benefits of the green roof of your home. Although it sounds expensive, you will get a return on your investment in the coming years. You need to decide how much time and resources you want to invest in your green roof. Depending on your decision, you can choose one of three main types of green roofs:
- Extensive – low-cost maintenance requirements
- Intensive – the higher cost of maintenance requirements
- Semi-intensive – an average between the two above types
Extensive Green Roofs
Extensive green roofs are a prevalent choice for property owners, as they have a simple configuration and are not used as elevated gardens. They are reasonable for both existing and new roofing. They require a relatively thin amount of substrate (about 100 pounds for square foot) that supports a low layer of vegetation, about 80 – 100 mm in height, such as grass, moss, sedum or little blooms.
They have all the advantages of cooling and stormwater absorption that comes with a green roof but require very little maintenance. Sedum green roofs are the most well-known sort because of the solidness and low maintenance requirements for the plant. A simplified way to look at an extensive green roof is if you took your yard and placed it on your roof.
Intensive Green Roofs
Intensive green roofs are the type of green roof that makes your home stand out for the general public. These green roofs are ultimately an elevated park with shrubs, trees, gardens, sun based boards, enhancement spaces, etc. This requires a layer of developing medium/soil to support a lot of thicker vegetation.
Of course, the roofs have the advantages of cooling and stormwater absorption like the extensive green roof yet they also have the added benefits of creating livelihoods, and ultimately being a lovely place for recreation in an urban setting.
This type of green roof has a significantly higher cost of maintenance. Someone needs to spend time and resources to think things through. In addition, it is more difficult for structural engineers because the weight of the substrate expected to support intensive green roofs is about 200 pounds per square foot.
These green roof constructions are more common in bigger commercial development, including parks and gardens where recreational use is designed. Intensive roofs require a much larger substrate, as well as the need to develop a water supply system. This requires significantly more consideration and support.
Semi-Intensive Green Roofs
Semi-intensive green roofs are another type of green roof, which is usually a combination of extensive and intensive green roofs. This type of green roof has the advantages of each type and is based on the principles of extensive roofs.
These types of roofs with a greater depth of substrate growth (100 – 200 mm) can support a more significant variety of plants, but not bushes and trees.
One of the most famous green roofs in the world is Chicago’s City Hall, which is a mixture of intense semi-intensive and extensive green roofs.
Simple Steps to Your Own DIY Green Roof
You can install the green roof on an existing or a new home roof. If you start looking for step-by-step instructions for building a roof garden, you will find a lot of companies selling expensive things. So, having studied the Internet and found out the cost of installation, you may want to start building your own green roof. The extensive green roof is the simplest type to give it a go yourself.
You may want to check if your roof is strong enough to support the weight of a substrate and vegetation. Strengthen the roof, if necessary, with additional joists under the roof and steel frames.
A brief step-by-step direction for building the green roof:
(1) The very first step is to insulate your roof with a water- and root-proof membrane, such as a heavy-duty pond liner to seal all leaks in it.
(2) To retain moisture, roll out a moisture-proof coating that can resist fungi and bacteria.
(3) Cover it with the layer of small stones and large gravel or pebbles around the edge of the roof to provide drainage at the bottom.
(4) Finally, add a substrate layer of 7 to 20 cm thick depending on the type of vegetation. Use a mixture of a substrate of 70 percent inorganic material and 30 percent organic material for lush vegetation growth.
(5) Now you are ready for planting.
Composition of Plants for Green Roofs
Despite the fact that green roofs are usually planted with sedums and low grasses, the planting palette can be significantly extended to accommodate more than 100 types of plants.
The variety of plants incorporates local prairie and woodland grasses and forbs, solid decorative perennials and grasses, a few types of local and elaborate bushes, and some varieties of trees.
Your DIY green roof is ready. Over the years, you will enjoy all the benefits, including reduced energy bills and extra space for recreation. Would you invest in your own green roof? Please leave your comment below.