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Green Roofing Tips

Choosing the Right Soil for Green Roofing

Think green roofs are mere slabs of nature placed exclusively on the rooftops of corporate skyscrapers and couture-designed architecture?  Think again, please (we beg of you.) Green roofs are practical constructs that should be added to all buildings – tall and short, residential and commercial – as they provide numerous benefits to not only the environment, but to the architectural soundness of the artifice and even to your health.

 

Green roofs come in many forms, and whether they are of the extensive or intensive variety, having good soil is crucial to having a functioning green roof. Now, this can’t be just any soil that you picked up at your local nursery. Regular gardening soil will not work the same way on your green roofing, even if you plant the same flower or vegetable from your backyard. Soil used on green roofs is specifically engineered to make the most out of your green gardenscape without weighing down on the roofing structure or the insulation installation, which is something regular gardening soil can’t provide.

 

Choosing the right soil for your green roof can easily become a convoluted list of chemicals and organic processes that swing right past your head if you’re not a botanist or soil engineer. Here are some layman ways to identify the type of soil that is needed for your uncomplicated green roofing project:

 

What are you planting?

The types of plant you place on your roof are usually what determine the type of soil you use. Because green roofing structures aren’t able to support plants with expansive root systems, short plants like grass, flowers and easy-to-handle vegetables are perfect for the shallow soil depth that most green roofs are able to sustain. Small, local plants are a great way to take further advantage of being an eco-friendly roof. Larger plants like fruit trees and other small arbors should be placed in their soil pots to prevent crowding root space and over-absorption of nutrients.

 

What to Look For in Green Roofing

If there is one thing you need to understand about green roof-engineered soil, it’s that is needs to be lightweight. No heavy gardening soil, period! Though some roofs have structures that can handle a bit of extra weight, most will not, particularly residential roofs. It is wise to not take the risk of using regular soil and watching your roof cave in or experience leaking from oversaturation.

 

With that in mind, here are some other things to look out for when soil shopping: water permeability and retention, rot resistance, nutrient saturation, and balanced aeration. Do not be intimidated, as these are all simple concepts that are quite easy to understand once you move past the terminology.

 

No standards exist in the U.S. for green roof soil specifications, but they are generally determined by the depth and weight of plants, climate and roof irrigation. The latter is particularly important, as an imbalance in its structure could lead to all sorts of problems for the rest of the building.

 

Above all, soil is one of the most vital elements you should invest in for your green roofing, along with sound irrigation systems and contractors to verify the roof’s support structure. Don’t skimp on soil; your roof and its plants will depend on it for their longevity.

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