Why Would Someone Want A Green Roof On Their House?
Why Would Someone Want A Green Roof On Their House?
By installing a green roof, you may enhance energy efficiency while reducing the need for air conditioning. Plants absorb solar energy, lowering roof temperatures in the summer and increasing thermal efficiency in the winter by trapping heat inside.
It’s also more environmentally friendly than installing a conventional roof, as it requires fewer manufacturing resources and organic materials.
What Are The Layers Of A Green Roof?
There are about six layers of a green roof, depending on the type of green roof:
Layer 1: Waterproofing Membrane.
The initial layer of a green roof is critical to the life of the building envelope. Water is one of nature’s most damaging tools throughout time. (Take a look at yourself, Grand Canyon.)
It goes without saying that we should not build massive water-holding systems on rooftops unless the roof is protected from them, which is where the waterproofing membrane comes in.
This strong material is the foundation of every green roof. A green roof that leaks (regardless of how lovely it appears) are a failing green roof. Waterproofing membranes are available in a variety of forms and installation methods.
They can be burned, or hot mopped, have fluid poured to them or be placed down in premade sheets. When analyzing waterproofing membranes, redundancy and robustness are critical.
Layer 2: Root Barrier.
You don’t want roots burrowing into your roof, just like you don’t want water. Not only have the roots pierced the waterproofing barrier, wiping out its efforts, but they can also cause major structural damage. You require a barrier.
This barrier is often constructed of a flexible polymer (typically Linear Low-Density Polyethylene or LLDPE) that repels roots while containing no chemicals or substances that might negatively react with the roofing, soil, or plants.
Layer 3: Drainage Layer.
The drainage layer’s primary goal is to direct surplus water down a drain or scupper and then off the roof. There is a fine line between too much and too little drainage.
This is why no “one-size-fits-all” solution exists. Many considerations go into determining the appropriate drainage layer, including:
- a) Roof slope
- b) Drain amount and position
- c) Stormwater retention/detention
- d) Load capacity
All of these factors contribute to establishing the appropriate drainage layer for a certain project.
One of the essential functions of green roofs is the retention and detention of runoff. That is, they either cling to it or slow it down on its journey to sewers or natural rivers.
It is accessible to plants while on the roof and then exits the roof via evapotranspiration (the combined process of evaporation and plant transpiration).
Layer 3.5: Optional Water Retention Layer.
A water retention layer is optional, but it is a fantastic concept, so much so that it is becoming more common in green roof design. Because of the rising demand for roofs to store more water, this component is becoming increasingly important.
The first few hours of a rainstorm are always the most stressful on stormwater infrastructure. Thus, the idea is to postpone the roof runoff for as long as feasible.
It’s already passing through a green roof’s plants, substrate, and drainage layer. It takes considerably longer if you include a water retention layer.
Layer 4: Filter Fabric.
Green roofs are fantastic, but they would only contribute to stormwater problems if they added a lot of soil, organic compounds, or other media to runoff.
Of course, the fact that water initially passes through the plant and media layers is beneficial since it purifies the water by eliminating pollutants, toxins, and illness.
Still, you don’t want a slew of particles clogging sewers and water treatment plants (more than they already are). Furthermore, it would rapidly lead to clogged green roof drains, thereby converting your rooftop into a bathtub.
Layer 5: Growing Medium.
None of the layers of a green roof are more important to the good growth of plants than the growing media. Depending on the rooftop, plant profile, and individual designer, this might be “actual” soil or some synthetic growth media that mimics soil.
This layer also acts as additional water-retaining material, reducing the stormwater burden.
Layer 6: Plants.
The top layer of a green roof is certainly the most desired and allows the greatest potential for creativity.
Plants may be grouped in a variety of ways, providing limitless architectural, aesthetic, and functional options for green roofs. Because so many natural plants grow on roofs, finding a mix that will flourish in virtually any setting is very simple.
Some are meant to thrive in deeper “intense” soils, while others thrive on 3 or even 2 inches of soil, which is frequently what we’re working with around the margins of roofs. These are known as “extensive” habitats and often include any roof with 6 inches or less of soil or medium.
Additional considerations, such as shade or sun, moisture content, or structural demands, all influence the sorts of plants you may select.
How Is A Green Roof Constructed?
A green roof is composed of three layers: drainage, filter, and plant. Each layer must perform numerous duties to reduce the build-up’s total height and weight.
Drainage layer- It must provide adequate drainage to prevent retaining too much water. The filter layer must protect the building and roots from disease and pollution.
Plant Layer- It must hold the right amount of moisture, have a good drainage system, and provide a home with all the nutrients needed.
On top of these three layers is also an additional layer called Growing Medium, which has substances that feed the plants and help keep them healthy.