It's difficult to get rid of a comfortable sofa, even after years of use have taken their toll and caused the sofa to sag. The worse the sag gets, the more you will sink when you sit down. A sagging sofa is also less than attractive in your living room. Rather than saying goodbye to your beloved old sofa, take steps to alleviate the slump. Repair sofa sag by correcting imperfections in the wood frame, the springs and the cushions.
Turn the couch upside down and remove the staples that hold the fabric lining using a flathead screwdriver.
Inspect the couch's wood frame for any splits or cracks that are causing the frame boards to sag. If there is a split or crack, cut a piece of plywood with a saw to use as a splint. Hold the frame board straight and drill the splint over the broken area using wood screws.
Look for loose or stretched sofa springs. Sofa springs can be affixed with twine or with clips. Pull tight those sofa springs that have slipped from a clip or have become untied. Secure the ends in the hook of a sofa clip and screw the clip to the couch frame. Unhook or untie one end of stretched sofa springs. Pull them tight and reaffix them to the couch frame with new sofa clips. If they are severely stretched, replace them with a new spring. Cable ties can also be tightened around neighbouring springs to add an additional network of tension.
Re-staple the fabric to the bottom of the couch, using a staple gun, and flip the couch back over.
Examine your sofa cushions. If it seems the filling of a cushion is overly compacted and that there is a lot of extra space inside, cut a piece of foam padding with scissors to match the dimensions of the cushion. Unzip the cushion and insert the foam pad below the existing filling.