How to Fix a Saggy Living Room Couch

Buy a commercial product designed specifically to fix a sagging couch. Such devices are typically in the form of an adjustable platform that is placed beneath a couch's cushions. These products can be found in a variety of retail stores as well as online.

Use a piece of plywood, cut to fit your couch, underneath the cushions to prevent sagging. You can buy plywood at your local home improvement store or lumber yard. This is a cheap fix, but it can make your living room couch uncomfortably firm, so it is best used when you have very plush cushions.

Place a piece of high-density cardboard on top of your living room couch's springs -- this works best if the couch is only slightly saggy. Alternatively, use a high-density foamcore board, which can often be found at craft supply stores. If you want to make the seat a bit softer, put some medium or high-density egg crate foam on top of the cardboard.

Place very sturdy milk crates under the seat of your living room couch if its foundation is saggy. Be careful while lifting the couch; this is easiest to do if you have someone helping you.

Purchase a piece of very firm foam, with a density of 2.5 or higher, from your local upholstery shop or supplier -- this solution, though effective, can cost several hundred dollars. Ensure that you get the right size piece of foam by measuring your couch beforehand. To provide even more stability, place the foam on top of a plywood board, cut to the same size.