Green Roof Costs?

We just finished framing our house and have two roof areas (over our garage and our kitchen) that we had engineered to support the weight of a green roof. Both areas have a parapet and are set up perfectly for a green roof. I think the total square footage of those areas is about 500 sq. feet.

We asked our general to get us a quote to have green roof material laid down instead of the regular TPO roofing we are using. The estimate just came back at a little over $49,000.00

This seem ridiculous, plus we're on a budget. Has anyone else installed this material? I'm curious as to what other costs per square foot might be. thx!

I was a little off in the square feet, it is actually 965. Works out to be a little more than $50 per sq. foot.

That's still a ridiculous cost. The better system to use rather than a built-in greenroof system is a modular system. We just did the first residential greenroof in Georgia using a Greengrid Roof modular system. The beauty of this system is that all of the drainage layers, soil, and plants are in trays, so installation is simply putting it on the roof. Also, it gives you the ability to repair the roof without tearing the whole thing up. Once it takes, the vegetation will completely envelop the area and hide the grid from the trays. It's also about $15 per sqft.

Here some pics.

Previously wrote:

We just finished framing our house and have two roof areas (over our garage and our kitchen) that we had engineered to support the weight of a green roof. Both areas have a parapet and are set up perfectly for a green roof. I think the total square footage of those areas is about 500 sq. feet.

We asked our general to get us a quote to have green roof material laid down instead of the regular TPO roofing we are using. The estimate just came back at a little over $49,000.00

This seem ridiculous, plus we're on a budget. Has anyone else installed this material? I'm curious as to what other costs per square foot might be. the!

This may be a little late but I am just getting started with a great company that provides a modular system that is already completely filled in so you don't have to wait for plugs to grow in and may be priced in the same range or cheaper than the plug method.  Here is their website; globalgreenroofs.com 

From what I have seen out there this is the best product so far.  Feel free to contact me at my posted name at gmail.