Sofa Cushions Gone Flat? How to Fix Them (and When to Replace the Foam)

Quick answer: Flat sofa cushions are usually worn-out foam, or fibre and feather filling that has clumped or shifted. Plumping, rotating and re-stuffing help for a while, but if the foam stays dented when you press it, the lasting fix is new foam cut to the size of your covers. Adding a polyester wrap around the new foam gives a fuller, rounder look.

A sofa frame often lasts 15 years or more, but the cushions give up much sooner. The good news: you rarely need a new sofa. Here is how to work out what has gone wrong and how to fix it.

Why sofa cushions go flat

• The foam has broken down. Lower-density foam softens with daily use and slowly loses its bounce. The middle seat usually goes first.
• Fibre or feather filling has moved. Loose fills migrate to the edges and clump, leaving a dip in the middle.
• The wrap has compressed. The soft layer around the foam flattens, so the cushion looks thin even if the core is fine.
• The cover has stretched. A baggy cover makes a good cushion look tired.

Quick fixes to try first

1. Rotate and flip the cushions every week or two so wear is spread evenly.
2. Plump fibre and feather cushions daily: squeeze the sides together and knead the filling back into the centre.
3. Top up loose filling. Unzip the cover and add fibre fill to back cushions that have thinned out.
4. Air them. On a dry day, let cushions breathe so the filling can recover from moisture and body heat.
5. Add a layer. A thin firm sheet or a polyester wrap around tired foam can buy you some time.

These help fibre and feather cushions most. Foam that has broken down will not spring back for long, whatever you do.

The press test: is it time for new foam?

Unzip a seat cushion and press the middle of the foam with your palm.

• Springs straight back: the foam is fine. Try a new wrap or a new cover.
• Stays dented or feels thin: the foam has lost its support. Replace it.
• Crumbles or you can feel the frame: replace it now.

Our guide to replacing the foam, the cover or the whole cushion covers this in more detail.

Choosing replacement foam that stays firm

• Lux foam: firm and supportive, the best choice for seats that get daily use.
• High Density foam: a medium feel for everyday seats.
• Super Soft foam: for back cushions only, never seats.
• Polyester (Dacron) wrap: adds about 6 mm and gives the full, rounded edge you see on new sofas.

Foam for UK orders is made and cut in the UK by our partner GB Foam Direct, and it carries a 3-year warranty. If you are unsure of the feel, order one cushion first and try it.

How to measure for new foam

1. Measure the old foam edge to edge, or the inside of the cover seam to seam if the foam is missing.
2. Take the width at the front and the back, as sofa seats often taper.
3. Measure the thickness you want. Most sofa seats are 10–15 cm.
4. Note T-shapes around the arms and measure each cushion separately.

Our sofa cushion measuring guide shows each step in centimetres.

Order foam, covers or both

Order foam cut to size to go inside your existing covers, covers only if the foam is still good, or complete replacement sofa cushions. Everything is cut within ±1.3 cm of your size, and we send a spec sheet for approval before cutting. Delivery is free across the UK, with all duties and VAT paid, so there is nothing extra to pay when it arrives.

Frequently asked questions

Can you get sofa cushions refilled?

Yes. Fibre and feather cushions can be topped up with new filling. Foam cushions are refilled by replacing the foam inside your existing covers.

How do I make my sofa cushions firmer?

Replace the foam with a higher-density foam such as Lux, and add a polyester wrap for a fuller shape.

How long does sofa cushion foam last?

It depends on the density and how much the seat is used. Firm, high-density foam on everyday seats typically lasts several years before it softens noticeably.

Is it worth replacing sofa cushion foam?

Usually, yes. If the frame and covers are sound, new foam costs far less than a new sofa and makes it feel like new again.