How to Fix Sagging Sofa Cushions

Diagnose the Cause of Sagging

Sagging cushions usually have one of two causes: the padding inside has compressed, or the support underneath has weakened. Before you buy anything, remove the cushion cover and inspect the foam core. If the foam shows a permanent dent or crumbles when pressed, the material has broken down. If it springs back but the cushion still sits low, the problem may be in the springs or webbing below.

You can also do a simple recovery test: press your hand into the center of the cushion and see how quickly it returns to shape. If it stays indented, replace the insert. For more guidance, see our article on sofa cushion recovery.

Quick Fixes: Fluff, Rotate, and Add Filler

For minor sagging, you may not need new foam. Start by fluffing the cushion to redistribute the fill. Remove the cover and beat the foam gently, then replace it. Rotate the cushions regularly to spread wear evenly. If there is a hollow spot, add a layer of polyester fiberfill or a thin foam pad to fill it out. These steps can restore a surprising amount of comfort for just a few minutes of work.

If the cover is removable, you can also check for a zipper that lets you access the fill. See our guide on fluffing and reshaping cushions for detailed steps.

Replace Foam Inserts

When the foam core has lost its support, the permanent fix is to replace the insert. Measure the cushion width, depth, and thickness, then order a piece of high-density polyurethane foam cut to size. Choose a density that feels firm but comfortable; a slightly firmer foam will last longer and resist sagging. Avoid guessing the original spec, as most sofas use a mid-density core.

Before installing, check that the new foam meets the flammability requirements for upholstered furniture. The U.S. Consumer Product Safety Commission requires that resilient filling materials, including foam, pass a smolder resistance test when used in upholstered furniture. If you are reupholstering, the entire piece must comply with the same standard. You can read about the CPSC standard on their official page.

Insert the foam into the cushion cover, making sure it is centered. If the cover is worn or stained, consider ordering a new cover as well. For more detail, see our article on replacing cushion foam inserts.

Add a Foam Topper

If the foam is not badly broken but the cushion has become thin, a foam topper can be a quick fix. Place a layer of memory foam or high-resilience foam on top of the existing cushion before closing the cover. This adds thickness without the expense of a full insert replacement.

Cut the topper slightly smaller than the cushion so it does not bunch up at the edges. For a firmer feel, use a high-density topper; for extra softness, choose a memory foam version. Our memory-foam topper guide explains how to size and install it.

Inspect and Strengthen the Support Base

Sometimes the cushion is fine but the sofa base has sagged. Feel the underside of the seat: if you can press the webbing or springs down easily, they may be stretched or broken. Tighten any loose straps or replace worn webbing. Spring systems that have collapsed need to be repaired or replaced. A solid base is essential for cushion support, so do not ignore it.

Check the frame as well. A cracked or bowed frame can cause the whole seat to dip. See our article on sofa suspension for more on diagnosing base problems.

Prevent Future Sagging

Once you have fixed your cushions, you can take steps to keep them from sagging again. Choose a sofa with high-density foam and a solid spring system. Rotate and fluff cushions weekly to spread wear. Avoid sitting on the edge of the cushion, which strains the foam. Place a board under the cushions if the webbing has stretched, and tighten any loose straps. These habits will extend the life of your sofa.

If you are buying new, look for cushions with a removable cover and a foam core that has a high ILD rating. Check our guide on foam density and ILD to understand how firmness is measured.

Reupholster or Replace? A Final Consideration

If the cushion covers are torn, faded, or no longer fit after foam replacement, reupholstering is an option. A professional can rebuild the cushion with new foam and fabric, bringing the sofa back to life. However, reupholstering is a significant project and often requires a good deal of effort and expense. If the frame is loose, cracked, or the springs are beyond repair, buying new may be the more practical choice.

When you decide to replace, look for sofas with high-quality foam and a sturdy base. Choose a sofa that matches your size and style preferences. Our buying guides can help you compare options, such as best sectional sofas.

What to pick for your use

Questions

Can I fix sagging sofa cushions by flipping them?

Flipping can help if the cushion is flippable (has identical sides). It redistributes wear, but if the foam is broken, it won't restore firmness. Rotate and fluff first, then consider adding filler or replacing the foam.

How long do sofa foam inserts last?

It depends on quality and use. High-density foam can last many years, but lower-density foam may compress sooner. Signs like permanent indentations indicate replacement is needed.

Is it safe to add a foam topper to a cushion?

Yes, as long as you keep flammability in mind. The topper must be smolder resistant to comply with upholstered furniture regulations. Choose materials that meet the same standards as the original fill.

Can I replace just the foam without reupholstering?

If the cushion has a zippered cover, yes. Remove the old foam, insert the new one, and close the zipper. If the cover is not removable, you may need to open a seam or have a professional do it.

What if the sagging is due to broken springs, not the foam?

You'll need to repair or replace the spring system. This is more complex and may require professional help. If the frame is also damaged, replacing the sofa might be more cost-effective.

Can I use a memory foam topper on a sagging cushion?

Yes, a memory foam topper can provide temporary relief by adding softness and thickness. However, it does not address the root cause. For lasting support, consider replacing the foam core.