Why Do Curtains Shrink? And How We Guarantee They Won't

Shrinkage is the number one fear homeowners have about curtain cleaning — and with good reason. We've seen countless curtains ruined by improper cleaning. Here's what's really happening, and why our process makes shrinkage impossible.

The Science of Curtain Shrinkage

Curtain shrinkage happens because of one thing: water + heat + agitation. When natural fibres like cotton, linen, wool, or silk get wet, their molecular structure changes. The fibres swell, then contract as they dry. If this happens unevenly or under tension, the fabric shrinks permanently.

Why Natural Fibres Shrink

• Cotton: Can shrink 5-10% on first wash, 2-5% on subsequent washes. The fibres tighten when wet heat is applied.
• Linen: Shrinks 3-5% but can shrink up to 10% if washed in hot water. Very susceptible to heat damage.
• Wool: Shrinks dramatically (up to 30%) due to fibre scales locking together when agitated while wet — a process called felting.
• Silk: Delicate protein fibres that weaken and shrink when exposed to water and heat. Can lose up to 8% of size.

Synthetic Fabrics: Lower Risk, Not No Risk

Polyester, acrylic, and nylon are more stable, but they can still shrink if exposed to high heat (above 60°C). The synthetic fibres don't absorb water the same way, but the heat from dryers or steam can cause them to contract.

How Most Curtain Cleaning Causes Shrinkage

The Other Shrinkage Risk: Re-Hanging

Even if curtains are cleaned without shrinkage, taking them down and putting them back up creates its own risks:

• Curtains are stretched by their own weight when hanging. Removing them lets fibres contract naturally.
• Folds and creases set differently after removal, making curtains look shorter even if they haven't physically shrunk.
• Hooks, rings, or eyelets can be damaged during removal, causing the curtain to sit higher.
• Many homeowners struggle to re-hang curtains at exactly the same height, creating the appearance of shrinkage.

How On The Spot Eliminates Shrinkage Completely

Our No-Shrinkage Guarantee

We are so confident in our process that we offer a written guarantee:

What About Pre-Shrunk Fabrics?

Many modern curtains are labelled "pre-shrunk" or "shrink-resistant." While this helps, it's not a complete solution:

• Pre-shrunk means the fabric was treated before cutting — not that it's immune to further shrinkage
• Heat, agitation, and improper drying can still cause residual shrinkage
• The "pre-shrunk" treatment can wear off over time, especially with repeated exposure to moisture
• Lining fabrics may not be pre-shrunk even if the face fabric is

How to Spot Shrinkage Risk Before It Happens

If you're considering any cleaning method, ask these questions:

• Will my curtains be removed from the track or rod?
• Will water or moisture be applied to the fabric?
• Will heat be used at any stage?
• Will there be mechanical agitation or tumbling?
• Do you offer a written no-shrinkage guarantee?

If the answer to any of the first four questions is "yes" and the fifth is "no," your curtains are at risk.

Can I Prevent Shrinkage at Home?

The best home maintenance is no water at all. Here's what you can safely do:

• Vacuum regularly: Use an upholstery attachment on low suction. This removes surface dust without disturbing fibres.
• Shake gently: Open windows and give curtains a light shake to dislodge dust.
• Spot clean carefully: Use minimal water with a damp (not wet) cloth. Blot, don't rub.
• Air them out: On low-dust days, open windows to freshen curtains naturally.
• Never use a steam cleaner: The combination of heat and moisture is exactly what causes shrinkage.

The Bottom Line

Curtain shrinkage is 100% avoidable when the right cleaning method is used. The key is simple: no water, no heat, no removal, no agitation. Our on-site dry process was specifically designed around these principles.

We've cleaned over 5,000 curtains across Johannesburg — cotton, linen, silk, velvet, sheers, blackout, and everything in between. Not one has shrunk. That's not luck. That's process.