Building a Green Roof: What to Know Before You Grow

Here are three things to do before you start planting

“ Eco roof , ” “ live roof , ” “ plant roof , ” “ green roof”—enough roof to drive you up one . Whatever you call it , the plan of attack is the same : to plant directly onto a roof ’s surface . While that seems simple , the design and carrying out take some preparation .

A properly make immature roof consists of several layers design to protect your cap social system while retaining enough dirt and moisture for your plants . And it is n’t just for looks . A correctly installed green roof can cut overspill and coolheaded indoor temperatures . Cool , eco - friendly , and a new position to institute — it ’s no wonder this idea is so popular .

But before you scamper up a ladder to turn your unattractive flat or slightly pitched roof into a vivacious growing open , before the medium or even a individual industrial plant is put in , consult the master . The provision and engine room postulate is well deserving the investiture when it ’s done properly .

Know your restrictions

Look into your zoning , neighborhood restrictions , and indemnity coverage related to instal a green cap before taking any other action . Because many neighborhood connection apply uniformity of landscape and architecture , your association may not allow installation of a visible dark-green roof ; it ’s best to demand before you make the investing . Also , keep your insurance company cognizant of any structural alterations you make to your home . Because green - roof coverage is a gray region for most insurance company , it is bright to keep the lines of communicating open .

Make sure your roof is up to the job

First , evaluate the side of your ceiling . matte ceiling are easy and less expensive to mold with than sloped roofs , and some sloped roofs require a baffle system to obligate the land in place ; an extremely usurious auction pitch is not advocate for planting .

Second , ask a morphologic engineer to determine whether the existing roof ’s load - bearing capacity is adequate ; plan for an additional 24 pounds of weight per square fundament . And inspect the roof for signs of damage and article of clothing ; mend or interchange any area in interrogative sentence before continue with building .

Consider maintenance and access needs

Like in - earth gardens , rooftop landscapes require some care . Plan how you will weed and water your planting . Maintenance may not be the only reason you require to enter the roof ; a fleeceable roof may interfere with simple activities such as servicing the chimney , installing a orbiter dish , or hanging Christmas light .

Like the look of this green roof?

make this grow tapis — or one like it — by selecting plants that are gloomy maintenance , lie with the sun , and have shallow and drought - tolerant ancestor organisation . Choose a palette with contrasting colors and grain . Include plants with humiliated - maturation habits that provide twelvemonth - round seasonal interest . It ’s also smart to use plants that spread or ego - sow ; they will fill in fast , save you fourth dimension and money .

Chives

Name : Allium schoenoprasum(Zones 5–11 )

Why it works : Its short , bulbous rootage system tolerates wry , shallow soil . The lush unripened spikes add texture , and the pompon pinkish flowers add a sprinkle of colour .

‘Fuldaglut’ sedum

Name : Sedum spurium‘Fuldaglut ’ ( zone 4–9 )

Why it works : It tolerates ironic , shallow grime . It has vigorous , mat - forming , bronze - red growth that is evergreen .

‘Albus’ mother of thyme

Name : Thymus serpyllum‘Albus ’ ( zona 4–9 )

Why it operate : Its shallow ascendent demand well - drained filth . It spreads and is well divide to cover a prominent orbit .

From foundation to foliage, every tier of a green roof is essential

A complete green ceiling consist of five layers . Installed aright , these layers will protect your roof and mimicconditions get in nature , making it possible to transform your bare blank space into green quad .

1 . ceiling - pack of cards waterproofing

The base is the most authoritative element . Its role are to prevent water from leak through your roof and to protect it from root insight . Your current roof surface will likely suffice , but confer with your roofing contractor to confirm that it ’s up to the job .

2 . drain scheme

The pitch of your ceiling will determine what type of drainage system you need . system diverge from simple framework to single that channel water through V - work troughs . An efficacious drainage organization will manage Earth’s surface and subsurface water , transportation excess water supply to gutter and downspouts , and provide aeration to source .

3 . theme - permeable filter layer

The function of this layer are to hold the growing medium in position and to prevent small particles from washing out to the drainage layer and clot up the system . This simple mat filter can usually be incorporate with the drain stratum .

4 . grow medium

The growing sensitive retains wet , drain excess water , provides and absorbs nutrients , and anchors plants , while keeping the morphological load as light as potential . You require no more than a 6 - inch - thick level of mostly inorganic medium ; expanded remains and slating study well .

5 . Plants

Limit your pallet to low - grow , low - maintenance plants . detain off from deeply - root , tall industrial plant that can dry out and become a fire hazard .

— Lucie Snodgrass is coauthor with her married man , Edmund , ofGreen Roof Plants : A Resource and Planting Guide . They own Emory Knoll Farms in Street , Maryland .

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