To start, if you need to know how to remove the headliner check this link to my how to on removal... https://www.yourcobalt.com/forums/ins...headliner.html
The replacement of headliner material is pretty easy and straight forward if you follow these steps. Prior to this install I had attempted this about three times with failed end results.
What not to do: Initially when I did this project I used material from my local fabric store. Not only did I look ridiculous rummaging through piles of fabric at "Jo Anns" but I paid out the rear end too (mind you I tried this method more than once). Also, the spray adhesive you use will make a huge difference in whether or not you get sagging when the temp starts to spike around 100 degrees in the summer. Moral of the story, don't buy general adhesive from just anywhere.
What you will need:
1. Foam backed headliner upholstery: I bought a 63x60in piece and that was just big enough for the headliner, if you plan to do your visors you will need more. I bought mine off Ebay for roughly $25 and they typically ask $15 per extra yard which should be more than enough.
2. Headliner adhesive: I used 3M's Yellow super trim adhesive because of this statement "Designed for bonding vinyl tops, heavyweight liners and hood silencer pads where high strength and heat resistance are needed." (and I have personal interests in the co.!)
3. Utility knife
Step 1: Remove the material from the headliner itself. Start in a corner and peel it away. Pull the entire piece off making sure not to pull out chunks of the foam liner itself.
Step 2: Lay your new material over top of the headliner and make sure there is a good amount of extra material around all corners and edges.
Step3: Cut a rough outline with your scissors of the headliner leaving around 2 inches of extra material all the way around.
Step 4: Spray adhesive all over headliner as directed on can; should be two layers overlapping.
Step 5: Lay liner material on top and begin to press it into the headliner. Make sure you get all the crevasses like the visor depressions and spots where the headliner is bolted to the roof.
Step 6: Cut away excess material slowly as to not over cut. For this I set the headliner standing up and started on the left cutting down, rotating it as I cut away at each side. You will want to leave the excess on the front and rear of the headliner to fold over since there is no molding to cover up if you dont get a straight edge.
Step 7: Respray the edges and problem areas where the material is not sticking particularly well. I had to go around all of the edges and respray since I focused on the middle so much the first go around. Set in time is quick so you should only have to apply pressure for a few seconds.
Step 8: Use your utility knife to cut out the holes where the coat hook, visors, sun roof switch go. I suggest making your initial cut from the back side to make sure you get it right the first time, then opening the hole from the front.
Step 9: Let the adhesive set in before you put the liner back in. I let it sit over night.
Your end result should look similar to this!
Remember that all of the edges are held in by trim or shroud so you dont need them to look 100% perfect just as close as possible.
That's it! Please follow the instructions and you will have an amazing looking and feeling headliner. Do as I initially did and you will either live with your mistake or redo it. I'm roughly $150 deep in headliner material and spray, not to mention the wasted time doing it incorrectly.