decomposed granite cost
1 On average, decomposed granite can cost anywhere from $35 to $125 per square foot. 2  This is going to be for an average of 1â³ in depth. 3  The more you go depth wise, the more itâs going to cost. 4  For example, one cubic yard that is 3â³ deep will cover around 100 square feet.he price of decomposed granite depends on many factors such as the quality of the rock, the amount of rock that will be purchased, as well as the company selling it. How much does decomposed granite cost? 1  On average, decomposed granite can cost anywhere from $35 to $125 per square foot.