A small piece of the ceiling material I selected. It is 3 mm real wood plywood with a tough paper or plastic facing, which is very thin. I ordered 5 - 4x8 sheets of it, for about $25 a sheet. I found that I could have done the job with only 4 sheets by inserting a small patch in the cabinet over the stove. That is what I ultimately did, and have one sheet left over now. I also used 5 sheets of 1/2 inch R max insulation, and about two sheets of 1 inch R max. The additional insulation went behind the original plastic headliners, and in the walls behind the bathroom and closet areas.