Have you ever contemplated "greening" your roof or even your concrete sidewalk – to cool the home and prettify the neighborhood?

If so, make way to 20th and Sansom streets this week to discover  an eco-minded and easily installed  "Yard (for) Sale" product being introduced as part of the  8th annual DesignPhiladelphia festival running Wednesday through Sunday. The demo is in the street and on the sidewalk in front of the new Shake Shack  burger joint - which has already put the eco-product on its roof.

For added incentive, those stopping by Thursday from 5:30 to 7 p.m. also enjoy a free Shake Shack tasting of its "Concrete" custard desserts.

Dreamed up by the gang at Shift Shape Design, the green product is formally named Fairmount Living Tiles. Detailed by  CEO Mario Gentile, it's a combination of  elements - starting with interlocking, modular frames or tiles made of recycled aluminum and available in smaller home-sized (15 inches square, 4 inches deep) and larger industrial-grade (30 inches square) forms. The latter have already been scheduled for installation on the roof of Urban Outfitters HQ at the Navy Yard. Not incidentally, home owners and businesses enjoy  tax credit rewards  for installing a green roof.

Inside those square tiles goes a lining of burlap – recycled bags which started out hauling coffee beans to La Colombe and now also will serve  as the delivery packaging for the third element of the Fairmount Tiles which gets piled on top.  That is, a special lightweight soil from the Gaia Institute  composted from the likes of Halloween pumpkins and Christmas trees.

Even when fully saturated  with rain water and weighted with a plant medium (from Girard Supply Company), the tiles bear down only 10-12 pounds per square foot, so will not put un-due stress on any home owner's roof, said Gentile.  "You won't have to call in a structural engineer – usually required before a green roof installation – to cut a hole in the roof, check out the spacing and tell you the maximum load."

Shift Shape Design's Fairmount Tiles (named after prototypes already installed on Fairmount area roofs, as well as the park) aren't placed directly on the roof.  For proper roof material breathing, the tiles are separated from the rubber or tar paper with  feet and a polyurethane roof barrier.  The tiles also have irrigation drain holes, so as not to drown the grasses or plants you'll be growing in the soil.

How much is this product going to cost? Gentile hedges on that. "We won't really know until we go into (local)  production of the system next Spring. But we're aiming to make it the most affordable and flexible green roof  system you can buy."