What exactly is urbanite? Answer: broken pieces of concrete slabs. Yes, somebody named this cheap and useful material so coveted in haute green design. Considering the environmental benefits of permeable paving and the high cost of stone, re-using old slabs is a great way to create a new walk or patio for pennies.

Permeable paving allows for water to better flow down throughout your soil to recharge the water table than is the case with other types of paving. All that earth in between acts like a giant filter to remove pollutants from water as it percolates downward.

Flagstone patios made of individual pieces laid on packed sand are proving a popular way to create permeable paving. Natural stone is expensive, so many landscapers have turned to urbanite.

Since urbanite is not a product manufactured for sale, you might have to hunt for a good local source. Craigslist.com is the best place to find those near you who are busting out concrete and need it hauled away. Not all concrete is equally useful, however, so before you begin, consider these tips:

Strive for uniform thickness. Stonemasons know it's a whole lot easier to lay a flagstone patio with material that is all the same thickness. Just set grade and lay the pieces out and the surface will be all at the same level. When you're dealing with varying thicknesses, you have to take special care to set a surface that is uniform, which is a big job and not easy for a novice.

Seek workable sizes. Find a source that offers pieces that are broken up into similar sizes. Make sure they are sized so that a person can move the pieces around on a dolly without special equipment.

Even spacing and similarly sized fragments of uniform thickness make urbanite much easier to lay out.

Pool decks. Not all demolition projects result in clean slabs. Old concrete pool decking and patios that have been removed should be good options. Ask pool remodelers about any current demolitions. Contractors generally pay high prices to dump old fragments, so helping them out by hauling fragments away will be much appreciated.

Seek color. A friend once used old pink-tinted concrete patio fragments to make a patio that was a dead ringer for pricey Arizona flagstone. Tinted slabs are a real upgrade from the usual gray. Choose concrete tinted all the way through since those with only top color will reveal the gray at the broken edges. If you can't find slabs with color, explore acid stains at the home-improvement store as a way to warm up the look.