The top upholstery for a car, also referred to as the headliner, can easily fall into disrepair even though it is not frequently contacted. Torn or sagging fabric is not only unsightly, but can also be a safety hazard that obstructs the drivers view. Typically a sagging or torn headliner is caused by disintegration of the underlying foam. Repair can be done professionally, but excellent results can also be achieved at home with a few common tools and a little patience.
Remove the damaged headliner from the car. The headliner is held into place by molded trim pieces. Take off the trim pieces by removing the screws and retaining clips that hold them into place. The Chilton manual that is specific to the make and model of your car gives further guidance on disassembling the interior. Reference this manual to aid in the removal process, if needed.
Remove the damaged fabric and disintegrated foam from the front side of the headliner. Using a stiff brush, aggressively loosen and brush off all damaged foam. Work in a uniform manner using overlapping strokes and multiple directions to ensure the damaged foam has been removed. It is crucial to make sure loose foam has been completely removed because the adhesive cannot adhere to loose foam.
Measure the dimensions of your headliner. Lay the measuring tape against the contour of the headliner for both the length and width measurements.
Cut the foam-backed fabric. Set the headliner on the fabric and cut the measured dimensions using the general shape of the headliner as guide. Allow for a few extra inches on all sides so the fabric can be wrapped around and adhered to the backside of the headliner.
Glue the fabric to the interior-facing side of the headliner. Spray the headliner and the foam side of the fabric according to the manufacturer's instructions. The surfaces will be very tacky so it's important to lay it on the headliner correctly the first time. If you are working with a larger headliner, consider getting a friend to help you. Once the fabric has been adhered to the interior-facing side of the headliner, wrap the edges of the fabric around and adhere them to the back side of the headliner. Additional spray glue may be necessary.
Allow the headliner to completely dry then place it back into the car. Replace the trim pieces and secure them into place with the screws and retaining clips.