What is Green Roofing

Have you watched the movie sequel Lord of the Ring or The Hobbit?  If you did, then the picture above is no stranger to you. And I bet that one way or another, you wondered what it is like to live in such house, or more, dreamed of building similar house. Well, good news for you! You can actually achieve that and you can start by having a green roof. So let’s talk about green.

Green roof, also known as living roof, gives a lot of benefits aside from its gorgeous and lovely look. The main benefit of the green roof is its environmental sustainability benefits. This includes its natural thermal insulation property that gives natural coolness and reduces humidity; reduces noise pollution; natural pollutant filter from pollutants like carbon dioxide and heavy metals from rainwater; ultraviolet radiation absorption; low-cost maintenance; rainwater retention keeping sewers from overflowing quickly; natural insect habitat; and long life span, about 30 to 50 years depending on it structural support and maintenance.

A green roof is made up of different layers:

Roof Deck

Roof deck is the base of your roof. It must have a strong foundational structure to support the weight of the entire green roof. It should be covered with a waterproof layer like asphalt or bitumen felt then another layer for root resistance.

Drainage and Water Retention

This is where the excess water drains through. Layer of pebbles is perfect as the drainage. Larger pebbles should be in the bottom while smaller pebbles on the top. The large pebbles in the bottom ensure the exit of the contained water while the smaller pebbles on top filters the water.

Substrate

This is the growing medium of your green roof. It should be 70-200mm deep and the soil should be containing nutrients appropriate for the desired plant growth. Using top soil or garden soil with high organic content might cause overgrowth of vegetation. Aside from that, this kind of soil is heavier especially when wet. Thus it is recommended to use soil that is light-weight and has low organic nutrients. You can customize this by mixing organic material with inorganic material like crushed brick or expanded clay.

Plants

This is the last layer and the most awaited one. This is where you can decide which plant you’ll be using but not all plants you desire are advisable. There are lots of choices though, lots of varieties of grasses and flowers. However, there are two main factors you should consider in choosing your plant. First is how much maintenance you could provide and the second is how much sunlight your area has. You must also consider that thicker your plant be, the heavier your roof will become.

There are two kinds of plant perfect for a green roof. First are the sedums. These plants only require low maintenance all year round as it is used in elevated conditions. The second one is the wildflowers. Wildflowers can survive in a growing medium with low organic nutrients. You cannot just use any types of plants. Consider the root growth and the nutrient requirement.