My condo has a very small back yard, only about 300 square feet, which right now is grass. I am wanting to put patio stones in. I have heard from some people that I can just go right over the grass if I put down sylia sand since it does not compact. I have also heard from others you must dig up the sod. Please help! It's not cheap to by the stones so I would really like to do it right the first time and have it last.