One of the most common questions I hear about green roofs & vegetated roofs & garden roofs is: HOW MUCH DO THEY COST? Good Question. Easy Answer.
An extensive evergreen garden roof can be purchased and installed from a base price of approximately $6-8.00 per square foot for simple, one species installations to $12-$14 per SF for a moderately top of the line extensive garden roof with multi-texture, multi-color plan species.
Now, if you have more money than you know what to do with - then you can spend as much as you want per SF. I have seen some vegetated/garden roofs quoted in the $120.00 per SF range (YIKES!!!),
It is educational (and I highly recommend you do this if you are interested in green roofs) to go and talk to your local roofer that has experience with installing TPO roofs. A TPO roof is also a 'green' roof if it is white in color - because it will reflect heat! Usually those roofers who have experience in TPO know vegetated roofs also - but always ask them if their company (or parent company) sells green roofing systems. If they do, be sure to make sure you are receiving unbiased info). A good TPO experienced roofer is Rick Anderson with Delta Roofing in Jacksonville, Florida - call Rick at (904) 292-1592 - tell him you saw his name on Kevin's blog.
Green roofs are my passion, and I believe they are key to restoring green to the Urban Core! - Creating habitat, a sense of place, and resolution to stormwater issues.
Don't be scared off by a quote of $20-$40 per SF for a green/vegetated roof! Those complicated and expensive systems are not necessary!
Please - beware of green roofs that require irrigation. Please!!! - it is easy to grow an orchard on a roof with fertilizer and irrigation and cow manure and etc...
A doubter? Look around the next time you are driving through town at the volunteer plants that THRIVE in sidewalk cracks, overpass retaining walls, uncared for gutters, and more. I've never seen irrigation tubing here!
Now - if you are looking at a global system - greywater, reuse, rainwater catchment (Judy and I are members of ARCSA - check out www.arcsa.org), permaculture - then you may want to integrate recycle irrigation into your vegetated roof - but DO NOT BUY the story that you HAVE to have irrigation. I can show you plenty of applications that have successful and beautiful green roofs that grew up on only rainwater...
OK - want to DIY? email me at firstname.lastname@example.org
But before you go and spend $ 20+ per SF shop and compare.
One final tip of the evening. We take and set up light level and temperature recorders on roofs we are evaluating for plant applications. Spend some time to assess what you are working with - this is the first step to good planning.
One last final tip. If you want a top of the line extensive vegetated roof - low maintenance but lush, tropical and beautiful - one that will treat stormwater, provide urban wildlife habitat like you will never believe and create a sense of place your DNA will connect to - email me.
Happy Green Roofing!