re: Weed Eradication and Seeding Grass

If its hard and cracked like you said you are going to need to loose that topsoil before you through any type of seed down, otherwise youre wasting your time.

I would roundup, wait 4 days and roundup again. Wait another 7 days and Then i suggest you go to the box store and rent a power rake. Run that thing all over the lawn to loosen the soil, groom out and throw down ryegrass seed. It will be a quick sprouting grass but if it gets real hot there it wont do as well. Id never recommend zoysia but its a tough low maint grass. Personally i would stick with Bermuda. Good luck.

Ps dont use a tiller. It will prob grow too deep and result in even more weeds making its way up. Allow the grass you plant to grow to a good height before you cut and keep it on the high side to help block any weeds from sprouting.