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White, Blue, and Green Roofs

This might be new to our ears, aside from the commonly known aksteelking.com roofing types such as asphalt shingles, slate and tile shingles, metal roofing, and flat roof, there is actually roof types named before colors – green, blue, and white roof. Well, we can always call any type of roof as blue roof if it is painted blue, green roof if painted green and white if painted white. But obviously, that’s not what we are going to talk about. These types of roofs might have something to do with its name, but they’re more than colors.

Roofs

Let’s start first with the white roof.

White Roof 

White roof is also known as cool roof. It is painted with white coating that reflects sunlight up to 90%. It can bend during hot days because of its elastic property. Its solar reflecting property gives numerous benefits. Reflecting light means cooler building which minimizes energy use 10% to 40%, thus saving money from air conditioning. Since it lowers waste energy of ACs and other machines, it also lowers down the smog and CO2, which mainly causes global warming and climate change. Aside from these, having a cooler roof extends the roof life span because it prevents warping and cracking thus reduces roofing waste (another plus for the environment).

However, there are new studies that disputes it effect on the environment. Yes, it reflects light and heat, but that is not always a good thing. These suggest that the “cool” temperature is only in the roof level. Reflected heat is actually directed into atmosphere and is then mixed with black and brown soon particles which contribute even more to global warming. It might lower the waste energy from the air conditioning but not more than on how it increases the heat in the atmosphere. Aside from that, having cooler roof collects moisture on the surface of the roof thus inversely affects the algae growth.

Blue Roof

Blue roof is designed to hold rainwater temporarily during a rainstorm. This is best applicable to urbanized cities that have combined sewers. Keeping the rain water from reaching the sewers prevents the sewers from overflowing. Blue roof will then slowly release the rain water when the sewers are already capable of receiving it without overflowing. This protects the local streams, ponds, oceans, or other natural resources like fishes and vegetation from being contaminated.

Green Roof

Green roof is a type of roof that is completely or partially topped with vegetative layer, hence it is also known as living roof. It requires layers such growing medium and drainage layers. Although it is costly upon installation and structural requirement since it is heavy, it can save you money in the future because it is low cost maintenance. Aside from its environmental sustainability benefits (e.g. air and noise pollution treatment, natural cooling properties, and UV absorption), it is long lasting, from 30 to 50 years of life span depending on the maintenance and structural support and layer designs.

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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 Roofing

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.