Sagging or lumpy sofa and couch cushions usually just need new foam inserts in the covers you already have. Measure the covers, choose a foam grade and order replacement foam cut to size, and you can refresh your lounge without new upholstery.
Whether you're replacing one cushion or a full set, here's how to get it right the first time. Still deciding? See new sofa or new foam.
1. Measure Your Cushion Covers, Not the Old Foam
Old foam shrinks and softens over time, so it won't give you the right size. Measure the cover instead.
- Take the old foam insert out.
- Zip the cover closed and flatten it gently without stretching.
- Measure the width and depth from seam to seam.
- Measure the thickness from the side panel.
Our cushion cover measuring guide covers curves, odd shapes and whether to add extra for a fuller cushion.
2. Choose the Right Foam for Your Cushions
We stock a range of Australian made open-cell foams. These are the grades we recommend most often for sofa and lounge cushions.
| Foam grade | Type | Density | Feel | Best used for |
|---|---|---|---|---|
| N30-130 | Premium | 30kg/m³ | Soft/Medium | Everyday sofa seat cushions and backs |
| N31-190 | Premium | 31kg/m³ | Medium/Firm | Sofa arms, firmer seat cushions |
| H35-200 | Heavy Duty | 35kg/m³ | Medium/Firm | High-use seating, slim-profile cushions |
| N23-130 | Medium | 23kg/m³ | Soft/Medium | Back cushions, sofa backs, ottomans |
| DF-FIRM | Reticulated | 32kg/m³ | Firm | Outdoor seat cushions, marine use |
Happy to cut your own? Each grade links to its full foam sheet. Otherwise, we'll cut it for you in step 3.
Thickness matters as much as grade, and thin seats usually need firmer foam. See our foam thickness guide, foam grades explained, or the foam technical brochure (PDF) for full specifications.
3. Order Replacement Foam Cut to Size
Once you've measured and chosen a grade, the foam calculator lets you:
- choose the closest cushion shape
- enter your exact sizes in millimetres
- pick what the cushion is for, such as a sofa seat, backrest or outdoor use, so you order a suitable grade
- choose your foam grade
- add a Dacron wrap if you want one
Your price shows as you build the order, so you can compare options. Every cushion is cut to order in our Chester Hill workshop, ready for delivery or click-and-collect.
Adding Dacron? It's a polyester fibre wrap that rounds the edges and helps the insert slide into the cover. It's a finish layer, so keep the foam measured to the cover. The Dacron wrap guide shows each wrap style.
4. Fit the Foam into Your Covers
- Fold the insert slightly, like a taco, and guide it into the cover.
- Take your time around corners and boxed shapes.
- Zip it up, then reshape and plump the cushion.
If it's a tight fit, a little silicone spray helps it slide in. A Dacron-wrapped insert can feel snug, which is normal and gives the smooth, rounded finish. New foam may feel firmer at first and relax with use.
Foam arrived compressed? See how to unpack your new cushion foam before fitting it.
Sofa Cushion Foam FAQs
Yes. That's the usual way to do it. Measure each cover and order foam inserts cut to fit, then fold them in as shown in step 4.
There's no single best grade. N30-130 is our everyday choice for seats and backs, while N31-190 or H35-200 suit firmer or high-use seats. Thin seats usually need firmer foam.
Yes. Measure that cover and order just that insert. New foam may feel firmer than the older cushions at first, and it relaxes with use.
Ready to Refresh Your Sofa?
Price your cushions online, check our foam FAQs, or visit our Sydney showroom for advice in person. Here's why Australian made foam is worth it.