We got our mats at an RV show from J&J Sunshades located in Lake Wales Florida. These mats have served us well over the past 2 1/2 years and still look like new and they won't kill the grass. They have standard sizes such as 8X9, 8X14, 8X18 and 9X12 or they will build you a custom mat. They also make custom Sunshades.
J&J Sunshades