Question
we tilled our lawn added about one to three inches of top soil.
Laid the sod then watered,had a lot of rain last night,
Went out this morning to move sprinklers.
The grass was very sponge leaving foot marks in the sod.
What is the best way to correct this problem.
Thanks Jim

Answer
When you tilled the lawn and added topsoil, you introduced a lot of air spaces in the soil. You could even say you "aerated" the area. The weight of the sod pieces will start to squeeze this air out. Watering and rainfall introduce water in much or all of those air spaces. When you walked on it you exerted more pressure (your body weight on your footprint area) on the sod and left footprints.
You want to retain the aeration as much as possible but over time, the whole lawn will subside no matter how imperceptibly. A light rolling will speed up the process and will help the sod to knit with the underlying topsoil.