Laying Sod Over Grass Without Tilling

Q: I know it likely is not good gardening, but is it permissible to lay sod over scalped existing grass?

A: You might lose a lot of sod if you do it this way. Those grass roots under the sod will dry out in a heartbeat if the are not touching the soil underneath. They can’t be “close to” the soil, they have to be touching something to wick water into the young grass plant. You could try rolling the sod but damage from using a roller too much could be a problem.