Why Do Clothes Shrink in the Wash?

Ever wondered why some of your clothes are more prone to shrinking than others? Well, the truth is, there are a number of reasons why clothes shrink when washed. On the plus side, the majority of these can be avoided with a little extra care. 

So, if you’ve recently reduced your favourite jumper to a child-size version of its former self and want to avoid a repeat, look no further. In this post, we’ll cover why clothes shrink in the wash and some top tips to prevent it. 

3 Ways Your Laundry Can Shrink

1. Felting shrinkage 

Felting shrinkage is something that can happen to clothes made from animal fibres over time. When fabrics like wool or cashmere are washed in hot water, the surface scales of the fibres open up and water gets trapped inside. As the fabric dries, the fibres contract and knit together. This causes the fibres shorten and your clothes to shrink the more you wash them.

2. Relaxation shrinkage

Other natural fibres like cotton, silk and linen are also affected by the laundry process. As these fibres are naturally curly and fuzzy, they are stretched out and straightened before being woven into clothing. However, when washed, these absorbent fabrics soak up water and their fibres swell. 

As a result, any tension set into the material during manufacture is released and the fibres start to return to their natural form. This relaxation can lead to a small amount of shrinkage, with silk being the worst affected fabric.

3. Consolidation shrinkage

Consolidation shrinkage, on the other hand, tends to be more dramatic. If your clothing falls victim, you’ll likely notice it after washing a new item for the first time. 

This type of shrinkage happens when moisture from your washer and heat from your dryer are combined with the mechanical agitation of the machines. Much like the first two forms of shrinkage, fibres can curl up on hot cycles, while the fabric’s tension can be relaxed by the tumbling motion.

 

Other Factors Affecting Shrinkage

Fabric weave

Generally speaking, tightly woven fabrics like denim are less likely to shrink in the wash. This is because it’s harder for water and steam to penetrate the fibres and deform the material. 

In contrast, woollen jumpers with lots of air pockets are highly prone to shrinking, as the fibres will contract tightly if exposed to high temperatures. 

Moisture in the fibres

Another factor that can affect whether clothes shrink in the wash, is the fibre’s natural moisture. Fabrics with a high moisture content like wool (around 14%) are more likely to shrink if overdried, due to the fibres constricting. 

With just 7% moisture, cotton fibres can withstand a little more heat. In contrast, synthetic fibres like polyester have no moisture content and therefore won’t shrink at all.

Washer or dryer cycle

Excess heat and liquids aren’t the only things that can cause clothes to shrink. As well as choosing the right temperature for washing and drying your clothes, you should also consider drum speed. 

Essentially, the more agitation i.e., the harsher the tumbling motion, the higher the risk of shrinkage. 

Top-loading machines with centre agitators are the biggest culprits, so avoid these if possible. And, if washing a delicate fabric, opt for a gentle cycle.

 

How to Stop Your Clothes Shrinking in the Wash

• Follow the care label – Always read the care label in your clothes and follow the advice. If tumble drying isn’t recommended, don’t tempt fate. Instead, hang the item on a washing line, clothes airer or dry flat if advised. Tip – place items near a radiator to speed up the process.
• Use cold washes when possible – Unless your clothes are really dirty or need disinfecting (e.g. gym/ work clothes), stick to cold or 30°c wash cycles. Cold water is less damaging than hot water, so always choose a cooler cycle if you’re not sure how a particular fabric will fair.
• Use fabric-specific cycles where possible – For instance, many washing machines have dedicated wool and silk cycles. Alternatively, choose a delicates or hand wash cycle for minimum agitation.
• Dry on a low heat – If using a tumble dryer, dry your laundry on the lowest heat setting you can. When the cycle ends, remove your clothes straight away to avoid over-drying. It’s also a good idea to either hang or fold your items soon after to help maintain their shape.
• Choose synthetic fibres for an easier life – If this all sounds like a lot of effort, make sure you’re choosing fabrics with little risk of shrinking in the first place. Synthetic fibres like polyester, nylon and acrylic have no water content and are treated with chemicals for durability, so won’t shrink in the wash. Clothes with a mix of natural and synthetic fibres are often most comfortable.

You can also buy pre-shrunk items that should hold their shape and size after being laundered. Just take a look at the care label to find out!

We hope this post has answered all of your questions about why clothes shrink in the wash and how to avoid it.