Question
We purchased a home with a sodded yard.  Evidently the sod never took root.  We had the lawn aerated and thatched with the hope of taking care of the problem.  However,during an extremely hot, dry spell some of the sod died off and we could actually lift it off the soil bed. What is the best way to take care of the problem with the least expense. Can we overseed or do we need to till and plant the entire area.  We recently installed a sprinkler system  

Answer
Hi Peggy;
If thatch was the problem, the thatch would be under the sod, so aerating would do nothing about the problem.
Thatch happens when there has been shallow watering and the roots have come to the surface of the soil to get water, and they die, trap other lawn debris and form a water-proof pad that will not let water get through to the roots.
I water with soaker hoses or hand held hose. Sprinklers waste too much through evaporation, and in temps in thew 90s and above, you can lose as much as 50% through evaporation, but you pay for all of what goes through your meter.
The sod had to be kept watered so that the roots can grow and get deep into the soil. The deeper the roots system, the better your lawn will fight off extreme summer heat or winter cold, or droughts.
Water till the water starts to run off, then turn off the water and let it soak in for an 30 min to an hour, then turn the water on, and do the same thing, untill you have soaked the soil down to at least 6 inches.
Deep watering like that will prevent thatch building up.
We had a bad thatch pad over the yard when we bought this house 42 years ago. I dethatched it, and have watered to a deopth of at least 6 inches ever since, and there has never been another thatch problem.
Switching to an organic program will save you a lot of money and work, and give you MUCH better results.
If you would like more information on organics, write me. I am happy to share what I have learned.
Charlotte