What could make the headliner to sag? It could be an old car, poor maintenance, or that long trip you took in the sunny (aka HOT) southern California. Yes, overheating, just like lack of upkeep and dampness, can make the fabric slump by dissolving the glue that holds it to the roof frame. Over time and due to extreme weather conditions, the fabric may become loose and get separated from its backing board. This condition is known as ‘sagging headliner’, which you sometimes cannot avoid repairing because it gets in the way. Specification: .