What Is a Living Roof? Green Roofing Guide

The increase in commercial and residential buildings has reduced green spaces and the destruction of natural habitats. One way that humans can reduce the impacts on the environment is by installing living roofs. This trend has gained vast popularity in densely populated cities. The projected annual growth rate for the vegetated roofs between 2020 and 2027 is 17%. Here is a detailed piece covering the basics of this roofing style.

What Is a Living Roof?

A garden roof is a design that involves deliberately growing vegetation or developing wildlife habitat on the roof. People use these spaces as farms, research centers, or parks.

Different Types of Green Roofs

There are two categories of roof gardens. Extensive garden roofs work well for residential premises and smaller commercial settings. They can support about four to six inches of soil and 25 pounds of vegetation per square footage. These roofs are lightweight and require little maintenance. Mostly, you use drought-resistant plants on these gardens, and their primary purpose is to create a habitat for plants and animals.

On the other hand, intensive green roofing can hold around 150 pounds of vegetation per square foot. So you can plant bushes and small trees. Such gardens will require soil that supports thicker vegetation. Mostly, you will find this roof type on large commercial buildings. These spaces offer entertainment grounds and include park features like shrubs, pavements, and water. Some people even use these spaces for urban food growing.

How to Install a Green Roof Garden

The steps involved in installing green roofs may vary slightly based on your goals and needs. You will first need to consult a structural engineer to confirm whether your house can support such a roof. You can proceed with installations after approval. When building green roofs, there are several vital components involved. They include:

Waterproofing Deck

The first process is to install one or more waterproofing materials over your roof to protect the structure. These membranes may contain asphalt, bitumen, or resin.

Insulation

If you are looking forward to increased energy efficiency after installing a garden roof, ensure that you add some insulation. This is particularly beneficial if you live in colder climates.

Root Barrier

The root barrier goes above the waterproof membrane, and it mainly prevents the roots from growing through. Some plant species have very aggressive roots that can damage other roof components.

Drainage Layer

A drainage membrane diverts excess rainwater to the drainage to prevent moisture build-up. If water accumulates on the roof, it might cause too much weight compromising your house’s structural integrity. A drainage layer will also prevent roots damage.

Filter Layer

This layer prevents debris from the soil and other substrates from clogging the drainage membrane.

Growing Substrate

Put some lightweight soil to support plant growth. You will have to use lighter and porous substrate for the intensive roofs. Green roofs substrates consist of perlite, peat moss, medium clay soil, and pumice.

Plants

Plants make up the top layer of this roofing system. You can choose how you want to plant the vegetation on your building. One option is using vegetated mats. For this option, the supplier grows plants in a different place. When mature, they will cut both the substrate and plant into a mat then lay them on your roof.

Another method is by using trays. You put the substrate in a tray then plant your vegetation. Once mature, you directly transfer the trays to the roof. The benefit of this method is that in case your need roof repairs, the contractor will safely remove the plants without disturbing the growing area.

You can also lay the substrate on the roof for more extensive gardens then directly plant your vegetation. For a naturalized green roof, lay the substrate and wait for native plants to grow.

Suitable Green Leafs Plants

Today, various companies supply green roofs plants and pre-grown solutions. You can choose to use native plants on your roof to create habitat and food for bugs and other wildlife in the biodiversity. Another great option is to use productive plants. Any vegetation you grow in your yard will do well in your roof garden. The only restriction is tall plants with aggressive growing roots. If you want the roof garden to serve more as a park, use landscaping plants instead.

One popular roofs plant is sedum. It’s a short shrubbery, tolerant to high temperatures. If you opt for the flowering species, your roof will have an appealing array of colours during the growing period. Once the flowers fall, they quickly decompose and enrich the soil. Choose drought, wind, and sun-resistant plants for your intensive garden. Some options you can use for the extensive roof garden include:

  • Moss
  • Asplenium trichomanes
  • Sempervivum
  • Polypodium vulgare

Benefits of a Living Roof

There are multiple reasons why you would want to install a garden roof. It benefits your house, the environment, and the entire community. Here are some advantages of living roofs.

They Act as a Form of Insulation

These eco-roofs reflect the sun’s heat in hot months and help maintain heat in the winter. They, therefore, stabilize the temperature in a building reducing heating and cooling costs. Vegetated roofs decrease energy use by 10% over the winter.

They Improve a Building’s Appearance

Roof gardens can support different plant species, which helps a building blend into the natural environment.

They Help with Storm Water Management

The vegetation on your roof will absorb a considerable amount of water in the rainy season. If most people install these roofs, it can help cities manage storms and lower strains on the local sewer system.

They Promote Biodiversity in Urban Areas

The central role of the living roof system is to replace the ecology occupied by buildings. They provide a safe space for natural plants and wildlife to thrive in urban areas.

They Improve Air Quality

The plants on the roof absorb air pollutants like carbon dioxide and reduce toxins. This contributes to a cleaner and safer environment.

They Increase Property Value

A house with a garden roof will have a higher resale value and attracts more potential buyers.

Extends Membrane Lifespan

The vegetation acts as a barrier to the roof membrane protecting it from harsh weather elements, increasing its service life.

They Promote Plant Production

Roof gardens create a unique opportunity to plant food and other vegetation in urban areas.

The main disadvantage associated with this roof style is the high installation cost. When wrongly installed, roof gardens can also damage your property.

Maintenance Tips for Green Roofs

The vegetation on your roof will require water and nutrients to grow healthy. So, water the plants during the dry season using drip or spray irrigation, especially in commercial buildings. For the intensive roofs, you need to mow the gardens and trim the plants from time to time. Also, inspect the garden often and replace dead plants.

The Bottom Line

Green roofs create visual enhancement on building, positively impact environmental sustainability, and help us exploit spatial opportunities for enjoyment. Some cities even offer incentives to encourage home and business owners to adapt garden roofs. You can be a part of this transformation by visiting walkerroofingandconstruction.com and contributing a noble cause to society.