How long was the Bermuda covered with plastic, and how long has the plastic been removed?

The Bermuda was covered for 8 weeks. We have not yet removed the plastic because I'm not yet sure if we should add topsoil or remove all of the dead bermuda first. I looked under the plastic, and all of the bermuda and weeds are white and dead.

Kill it again. White isn't dead. It's zombified but still growing. And that's why it's a popular lawn grass. It's tough as all get out.

Hollysprings: When you say kill it again, do you mean that I should continue to leave the plastic on for even longer? Or should I do something else to really kill it off?

"Kill it again". lol. Classic. You might want to try blocking out the sun with a commercial grade weed control fabric and having the plastic over that to keep out water. Seems like you're giving the grass and weeds a steam bath.