No need to till. And it will only bring up more weed and Bermuda grass seeds to the surface where they'll germinate.

Get the sprinkler system installed or the existing one in working order. Water everyday, twice a day for two weeks. This will germinate a good percentage of the weed seeds still in the ground. Spray them again or simply shave them off with a good, sharp hoe (don't dig or pull).

Marathon is a terrific lawn for most of California.

All of the above assumes you want a lawn because you have small children. I hope you don't mind that I bring up the option of a lawn alternative.

Joe

My only question is related to the texture of your soil and its compaction. Old lawns grown on a heavy clay are often so compacted the drainage, and oxygen in the soil are serious impediments to the establishment of new sod. In such a case I would consider correcting this problem before the investment in new sod. If you will be installing a sprinkler system you will soon find what your soil problems are as you dig. Al

Thanks for the advice! A lot of the grass did seem to die, we used a sod cutter to shave it up (we are going to cover up and compost the dirt and dead weeds for the season on the side of the house.

It looks like we got below the roots, but some seed did spread, so we will do sprinklers and then try to spray again. The soil is pretty compacted so I think we still might till.

and Joe, we do want some grass for the kids, but we did try to minimize considering the poor (and expensive) water issues on southern CA by ringing the yard with a 4' planter bed and extending our pavers into the middle...but those kids do love to roll in the grass=)

I learned my lesson personally laying sod twice and never had any luck. Now I know that eventhough I purchased the sod from two different sources if there is any dry grass showing even a drip which I would cut away, the sod is dry and older and pass it up an wait for fresh or order it beforehand. I fyou used a product like Roundup on the bottle it states to wait a couple of weeks. I saw some nice pre-dirt before you put the sod.

Round up has a temperature requirement to work. If it's not warm enough, it will not be translocated and kill the bermuda rhizomes. You don't state where you are, but if it wasn't in the 70's for a few days after you sprayed, you may have only killed the grass blades, not the stems.

Is there an optimal temp for laying sod, or is there a maximum temp during summer months.

You are better off waiting for autumn if you are planting a cool-season grass (Fescue--Marathon is Fescue). Bermuda types are warm-season so now is tolerable if you are willing to water like crazy.

If you want to go from bermuda to fescue you really really need to make sure the bermuda is totally dead because it will ruin the fescue. This means killing it all then watering to see if it will come back, killing that, watering to see if it will come back several times. Bermuda can have viable roots 2 or 3 feet down just waiting for moisture to start growing.