About Green Roofs
Green Roof Applications -- Benefits of Green Roofs -- Our Services
Green Roof Applications
Basic Composition
- Roof deck: typically plywood for residential; concrete or steel for commercial
- Waterproofing: membranes range from modified bitumen to rubber/plastic hybrids such a thermoplastic polyolefin (TPO) or modified polyvinyl chloride
- Drainage and root barrier: drainage may be as simple as pea gravel; we prefer synthetic materials with built-in root barrier and landscape felt layers
- Growth medium and plants: choice of plants emphasizes lateral rooting, light-weight, and low maintenance; growth medium provides nutrients and structural support
- Fireproofing: a gypsum board is placed under the membrane if the deck is combustible; the growth medium and plants are also fireproof
- Green roofs can be installed on relatively flat to steeply sloped roofs; most are from 2 - 25% or 0.25:12 - 3:12
- Flat roofs offer accessibility and ease of installation; sloped roofs have greater visibility, but may require additional measures to stabilize plants and growth medium
- Intensive green roofs: > 6 inches of growth medium with saturated weights from 50 - 300 lbs/sq ft; many plant choices including small shrubs or trees; can include seating or walkways
- Extensive green roofs: 2- 6 inches of growth medium with saturated weights of 10 - 35 lbs/sq ft; some limitations in plant diversity and accessibility but provide all the other benefits
- Modular green roofs utilize pre-assembled units whereas loose-laid integrate separate layers and offer more versatility as well as lower cost
- Can be included in plans for new construction or added to exisiting buildings
- Beauty & aesthetics: provides all the amenities of ground-level gardens
including re-connecting people to nature - Habitat restoration: replace building footprint; can use native plants and
thus provide a haven for local birds and butterflies - Increase life of roof: reduce UV damage and diurnal T fluctuation;
lower maintenance costs - Insulation & energy efficiency: lower heating and cooling bills
- In densely populated regions, can alleviate urban heat island effect due
to heat absorption from typical roof materials such as bitumen - Filters pollutants and carbon dioxide from the air; adds oxygen
- Storm water run-off: green roofs reduce the rate and quantity of storm water run-off and may mitigate or even eliminate the water run-off pollution problems associated with excessive urban development
- "A study conducted by Environment Canada found that a 6% green roof
coverage in the City of Toronto would lower the temperature by 1 - 2 degrees Celsius (1.7 - 3.6 degrees F)." (Green Roofs for Healthy Cities) - A green or ecoroof is self-sustaining and regenerative; once established it needs no fertilizer, irrigation, or pesticides, and minimal maintenance (once or twice per year)
- Consulting: we can help you determine whether a green roof will work well
with your building situation and intended usage - Retrofitting: we can retro-fit existing roofs to accomodate vegetation; structural reinforcement may be needed depending on planned usage such as accessibility
- Plant layout and design: we encourage the use of native and drought-
tolerant plants, incorporating beauty and aesthetics - Installation: including all or any of the elements of a green roof, from the roof deck and waterproofing to the growth medium, plants, and any hardscape elements such aswalkways, etc.