Sagging Sofa Cushions: What to Do (Foam, Care and Lifespan)

Short answer: It is normal for a sofa cushion to settle a little in the first months — the foam loses a small part of its volume during the initial period of use and then stabilises. This is called "settling" and is not regarded as a defect. However, if the cushion does not spring back when you press it with your hand, a permanent hollow has formed in the middle and you feel a difference in firmness between the two sides, the foam has tired; the solution is not to refill the cushion but to replace the foam. In a well-kept sofa, the lifespan of the body depends on the quality of the frame; the foam usually tires before the frame and can be renewed on its own.

Why do sofa cushions sag?

Sagging does not come down to a single cause. The most common causes, in order:

• Always sitting in the same spot. A three-seater has three seats, but everyone at home has a fixed place. The middle cushion stays empty for years while the cushion at the end carries the load every day. This is the single biggest cause.
• Low foam density. Density tells you how many kilograms one cubic metre of foam weighs. For the seat foam of home-use seating sets, a density between 30-35 is expected; in a significant share of Selishome seating sets this value is 32 DNS. Low-density foam sits comfortably in the first year, then loses its shape quickly.
• Fibre filling in the back cushions. Fibre behaves differently from foam: when pressed it flattens and does not recover on its own. If the back cushions are fibre, you get clumping rather than sagging; the solution is to fluff the fibre by hand.
• Sitting on the armrest. The armrest is not a structure designed for sitting; the support beneath it is weak and comes apart over time.
• A weak spring system. When the webbing or zigzag spring under the cushion loosens, the seat dips even if the foam is sound. If the cushion comes back when you stand up but the seat line stays low, the problem is not in the foam but beneath it.

We explained how to check these items before buying, with steps you can apply in a store, in our article how to tell a quality sofa.

Normal settling or a defect? A test to tell them apart

You can apply the table below right at your sofa.

↔ Scroll the table sideways to see all of it.

On the warranty side the rule is clear: foam settling and fabric fading are regarded as normal wear, not a manufacturing defect. On the other hand, frame breakage, seams coming apart and mechanism failure fall under manufacturing defects. We wrote the details in our article furniture warranty and after-sales; on all furniture, including seating sets, the warranty period is 2 years from the invoice date.

How do you restore a sagging cushion?

If the foam has not tired completely, the four steps below make a visible difference. Try them in order.

• Rotate the cushions and swap their positions. This is the most effective and cheapest solution. Turn them upside down, move the right-hand cushion to the left. When done once a month, the load spreads across the whole surface. On cushions with fixed seams you cannot flip them; in that case only swap their positions.
• Fluff the back cushions. Fibre-filled back cushions largely regain their volume when beaten by hand once a week. This solves half of what looks like a sagging problem.
• Air the cushion. Moisture slows down the foam's recovery. If the cover can be removed, air the foam in the shade for a few hours; do not put it in direct sun, as the foam yellows and turns brittle.
• Check the support underneath. Tilt the sofa onto its side and check the underside cloth; if you see a loosened webbing or a staple that has come out, the problem is not in the cushion.

It is best to make these steps part of your regular care routine; we gathered the periodic care list that applies to all furniture in our article how to care for furniture.

Foam replacement or a new sofa?

The decision depends on the frame. The rule is this: if the frame is sound, the foam is renewed; if the frame is gone, the sofa is gone.

You can tell the state of the frame with three checks:

• Hold it by the armrest and shake it. If the body moves as one piece, the frame is sound; if the armrest moves separately from the body, the joint has opened.
• Lift it slightly from one end. If you feel a creak, a crackle or flexing as you lift, the load-bearing structure has tired.
• Open the underside cloth and look. If there are no cracks in a frame made of solid and laminated material such as beech and plywood, that body deserves a foam renewal.

When the foam is replaced with foam of the same size and a higher density, it brings the sofa close to how it sat on the first day. But two warnings: having the replacement done by an unauthorised party voids your remaining warranty rights, and if the fabric has also tired, replacing only the foam is a half solution.

How many years does a sofa last? The four items that determine lifespan

It would not be right to give a fixed number, because the intensity of use determines lifespan. A sofa where four people spend hours in front of the television every evening and a living room set that hosts guests a few times a year do not wear at the same speed. The four items that determine lifespan are these:

↔ Scroll the table sideways to see all of it.

The practical result is this: when buying a sofa, put your money into the frame and the foam, not the fabric. You can change the fabric later, but you cannot change the frame. So once the durability threshold is passed, paying extra on the upholstery makes less sense; we explained where the threshold lies in our article what is Martindale.

7 habits that extend a sofa's life

• Rotate the cushions once a month and swap their positions.
• Break the habit of everyone having "their own place"; use the seats in turns.
• Do not sit on the armrest or on top of the backrest.
• Do not position the sofa close to direct sun or a radiator; both dry out the fabric and the foam.
• Vacuum once a week with a soft brush head; dust that settles inside the fabric wears the fibres.
• Blot the stain rather than rubbing it. We wrote the method by stain type in our article how to clean a fabric sofa.
• When moving, do not drag the sofa, lift it; dragging opens the joints of the frame.

If you have decided to move to a new set, compare by first asking about the frame and the foam. For example, in the Adalya sofa set the seat foam is 32 DNS density and the frame is beech and plywood; the Venüs sofa set, on the other hand, uses a hornbeam wood frame. You can compare the options in the sofa set category and follow the order of decisions in our guide how to choose a living room set.

Frequently asked questions

Is a sagging sofa cushion covered by the warranty?

Foam settling is regarded as normal wear and is outside the scope of the warranty. However, a break in the support under the cushion, seams coming apart or a broken frame are manufacturing defects and must be reported within the 2-year warranty period.

How often should sofa foam be replaced?

There is no fixed period; it depends on how heavily it is used. The measure is behaviour, not time: if the cushion does not spring back when pressed and rotating the cushions does not close the difference, it is time to replace it.

What should the foam density be?

For the seat foam of home-use seating sets, a range of 30-35 is expected. Foam below this value loses its shape in a short time. Softer fillings are used in the back cushions, and high density is not sought there.

Is putting a board under a sagging sofa a solution?

It is a temporary and problematic solution. A board stiffens the support, which is meant to flex; it throws off the seat height and speeds up wear by crushing the foam at a single point. The right solution is to repair the support or replace the foam.

Why does the cushion of a new sofa feel firm?

New foam is firmer than its designed feel in the first weeks. With regular use it settles and reaches its real feel. Using the cushions in turns during this first period also keeps the settling even.

Is it more sensible to renew the sofa or buy a new one?

If the frame is sound and you are happy with the model, renewing the foam and fabric makes sense. If the frame moves, the body wobbles, or the size does not suit your living room anyway, renewing would be a waste of money.