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How to use wool nappy soakers

Updated: Jul 14, 2023

A beginner's guide to wool diaper covers and how wool soakers work

Wool nappy covers may well be the most eco-friendly way there is of waterproofing your cloth nappies. But wool soakers can also seem very mysterious and scary - they're not really waterproof but rather moisture-wicking (huh?), they don't need washing that much (yay!), but instead they need some weird process called "lanolizing"? What on earth?

Well, you're in the right place. In the article below is everything you need to know about wool soakers and how wool nappy covers work.

I first came across wool soakers in the cloth nappy section of a parenting forum I hung out on a lot when my little one was small. I loved knitting so I thought I'd try making a soaker or two myself, and the rest is history!

Me and my wool soaker wearing son, happy on a swing

Want to learn a little more, and maybe try wool nappy soakers for yourself?

Read on for my tips on what diaper soakers are made of and how to use wool covers for cloth nappies.

What's in this guide?


What is a wool nappy soaker?

A wool diaper cover or nappy soaker is a layer of wool worn over a reusable cloth nappy, to stop moisture leaking out.

Most waterproof wraps are made from PUL (polyurethane laminate), which is basically fabric coated with plastic to make it waterproof. This is obviously much better for the environment than disposable nappies, because these wraps are reusable for years, but at the end of their life they're still non-biodegradable and will add to landfill.

But if you want to replace plastic with something more natural, you can use wool covers instead. Sounds crazy? I know! It's a weird idea to get your head around, but actually wool is surprisingly effective. Just think about how well sheep stay dry, and how fishermen have used woollen sweaters as protection from the wet for centuries.

Wool doesn't work quite the way that plastic does. Plastic covers act solely as a waterproof barrier to trap moisture in the nappy beneath. Wool is water-resistant rather than waterproof. It does hold the moisture in to a certain extent, but as well as that it absorbs moisture and holds it within the wool (wool can hold around 30% its own weight in liquid), then allows it to evaporate gradually from the outer surface where it has contact with the air.

This helps keep the nappy beneath drier for longer, which is great especially for nights when you want baby to sleep for as long as possible. It can also help reduce issues with sweat rashes, eczema and with super-strong wee when children are teething.

Wool is also anti-bacterial (which is why it doesn't need to be washed so often), and softer and more stretchy at waist and leg cuffs, reducing irritation. And of course, unlike plastic, wool is a natural material which will biodegrade once it's eventually worn down too much to be used any more.

How do wool nappy covers work?

  1. They form a water-resistant layer to reduce the moisture leaking out of the nappy beneath.

  2. They absorb some of the moisture that seeps through from the nappy and hold it within the wool.

  3. They wick that moisture out into the air from the outer surface of the wool cover.

In other words, they slow down the flow of moisture so that eventually, if there were no more moisture added, it would all evaporate from the outside of the wool soaker. This is why wool covers help keep baby drier than PUL ones do.

What are wool soakers made of?

Wool covers need to be made from real wool. Many people assume that because something's knitted, it's made of wool but this isn't always the case, particularly in the UK where any knitting yarn tends to be referred to as "wool", even when it's often man-made acrylic yarn (i.e. plastic). The yarn used to make wool soakers needs to be contain a high percentage of pure wool - the higher the wool content the better.

It's also important that the wool is not "superwash" wool, which is wool that's been treated to make it machine-washable. This kind of wool won't absorb and hold water in the same way as natural wool.

Many people (very rightly) have concerns about using wool because of how the animals it comes from are treated. It's important therefore to look for soakers made from sustainably and ethically produced wool, from farms where mulesing does not take place. There are more and more sustainable wools available, including some brands where the dyeing process avoids chemicals or uses the heat of the sun to set the dye.

Covers can also be made sustainably by using wool from second hand sweaters, either unravelled and re-knitted, or cut out and sewn into a soaker - the ultimate in zero waste nappy covers!

What is lanolin?

Lanolin is what helps make the wool soaker waterproof. Lanolin is found naturally in most wool and is similar to the oils on our own skin. It's what helps keep sheep dry when they're standing out in the rain!

When added to soakers (in a process called "lanolizing"), lanolin performs several magical tasks:

  1. Lanolin helps keep the wool water-resistant.

  2. Lanolin helps soften and smooth the wool so it's kinder to the skin.

  3. Lanolin turns into a sort of soap when moist, which means soakers are partially self-cleaning.

  4. Lanolin reacts chemically with urine, neutralising its odour (so if your soaker starts to smell of urine, that's a good clue that it needs re-lanolizing).

My personal experience using wool soakers with my baby

I've always preferred reusable items to disposable ones, mainly for environmental reasons, but also because I hate shopping! So when I became pregnant with my son (way back in 2005!) I was determined to use cloth nappies rather than disposable ones.

I also took up knitting whilst pregnant, as something useful to do when resting because of morning sickness and later because I hurt my back. And I was so excited when I discovered you could knit wool nappy covers, thus combining my passions for both knitting and saving the earth from extraneous plastic!

I did use a lot of regular PUL wraps with my son (as well as all-in-one nappies which have a PUL layer incorporated into them) but he did have several knitted soakers that worked really well. My favourites were actually a couple of pairs of wool trousers or "longies", because they didn't need trousers over the top in the winter, but together we also tried out a variety of different designs of knitted soakers and wraps.

Wool soakers for bigger children/adults

When I started WombleKnits, selling sustainable knits on Etsy, of course I included wool soakers in my product list! And very shortly after that I was approached to knit a larger, adult-sized soaker. I have no personal experience of using wool for older children or adults, but I know a lot about knitting so I took up the challenge and, after a lot of work and complex calculations, managed to scale up my baby nappy soaker knitting pattern to fit an adult. Since then I have knitted wool nappy covers for six adults with different shapes and sizes.

The obvious need for soakers in all sizes, not just baby sizes, spurred me to develop my knitting pattern to be customised to any dimensions required. After many months of hard work and help from my pattern test knitters, my Any Size Wool Soaker pattern is now available on Etsy, Ravelry and LoveCrafts.

The Any Size Wool Soaker pattern a variety of options for sizing and weight of yarn:

SIZING - 5 standard sizes from newborn to toddler, plus 1 standard adult size, or generate a pattern customised to your exact measurements

WEIGHT OF YARN - Knit the 6 standard sizes using worsted/Aran weight yarn, or generate a pattern for any weight yarn (e.g. chunky yarn for a thicker, quicker knit)

Plus complete pattern support from me if you run into any difficulties (technical or otherwise)!

How to use a wool soaker

A wool nappy cover can be used over any kind of cloth nappy, apart from all-in-one nappies which already have a waterproof PUL layer as part of the nappy. You can use a fitted nappy, or a folded terry nappy or prefold secured with a plastic fastener called a Nappy Nippa. Just pull the wool soaker up over it as you would any other nappy cover or pants.

Note: because wool covers aren't as immediately waterproof as PUL ones, it's very important to make sure the nappies beneath them have enough absorbency to hold the urine until the wool can wick it out into the air. You may find you need thicker nappies or to add more boosters than you would need with PUL covers.

When the nappy needs changing, if the soaker isn't very wet at all you can use it again right away. If it's moist or wet, you'll need to use another one (or a regular PUL cover).

Undyed wool knit nappy soakers drying on a line in the sunshine

Once it's off, you'll need to hang the wool cover to air. Hanging it outside is ideal as it will benefit from the fresh air and sanitising effects of sunshine (even when the sun's not out), but anywhere the air can circulate is fine. Over cot railings, over a clothes airer, on a clothes hanger with clips (especially near an open window) – whatever you have in your home that will work for you.

If you're out and about and the wool soaker is too damp to use again, pop it in a waterproof bag until you're home again and then hang it out to dry properly.

When to wash your wool diaper cover

Your wool soaker should only need washing every two or three weeks, or if it gets soiled. Sometimes you can just spot clean with a bit of soap and water if the soaker is otherwise clean and odour-free.

A guide to washing and lanolizing wool soakers will be coming soon - sign up for my newsletter to get notified when it's published.

Can you wear clothes on top of a wool soaker?

Yes, but there needs to be a lack of pressure against the wool. If the wool is holding water, pressure on any small part of the wool will cause that water to leak out. If you've ever hand-washed a wool sweater, you'll know exactly what I mean. The sweater can sit there, completely saturated but not leaking water, but the moment you start to squeeze or wring it out, the water just gushes out. You don't want this happening with your soaker!

So clothes or baby sleeping bags over the top of a soaker are fine but they need to be loose. Try going up a size, or buying clothes specifically made to fit over cloth nappies so there's more room in the nappy area.

You'll also need to make sure the nappy underneath the wool is well-boosted, so it can hold the moisture long enough for it to be wicked out into the soaker.

So what are the pros and cons of wool soakers?

Benefits of wool nappy soakers

  • They are made from completely natural, biodegradable materials instead of plastic

  • Wool is breathable, helping the wearer stay drier and at a more comfortable temperature

  • Soakers have soft waist and leg cuffs which can be more comfortable than PUL covers

  • Wool doesn't need to be washed as frequently as PUL

  • They should last longer than plastic nappy covers

  • Soakers and longies can be worn as an item of clothing, reducing the need for more clothes over the top

  • Most wool covers pull-up over nappy, so there are no complicated fastenings for other people looking after your child to get confused about

  • Wool is much more stretchy than plastic so soakers will generally fit a wide variety of sizes and can grow with your child to some extent

  • Or if you're a knitter you can make your own to fit your child perfectly

The same pair of wool longies being worn at different ages,m from 10 months to 17 months
This was my favourite pair of longies for my son and they stretched to fit him for a long time!

Downsides of wool nappy soakers

  • Soakers can be more expensive

  • Wool does need a little more looking after than plastic wraps do

  • You can't wear tight clothes over the top

  • You may need a bigger or better boosted nappy underneath

How can WombleKnits help you with wool nappy soakers?

At WombleKnits you can buy nappy soakers from newborn size all the way up to full size adult soakers. Check out my Wool Nappy Soakers page for:

  • - Wool nappy soakers in sizes from newborn to adult

    • ready made

    • made to order

    • custom knit to your own measurements

  • Any Size Wool Soaker knitting pattern

    • pdf pattern for standard sizes using worsted weight wool

    • Excel spreadsheet patterns (one using metric measurements, one using imperial) to generate a pattern customised to your own measurements and/or using a different weight of wool


How many wool covers will I need?

Ideally at least three. One in use, one airing to dry, and one or more as backup.

Do wool soakers itch?

A lot less than you might think! Soakers are generally made from very soft wool like merino wool or alpaca mix, which is far less irritating than the wool you might use for a sweater or jacket. Lanolizing them helps soften the fibres even further. In addition, at least if you're using a soaker rather than longies, very little of the wool surface will be touching bare skin (most of it's over the nappy). And the ribbed waistband and leg cuffs are very stretchy and far more comfortable than rigid PUL fabric.

Are wool nappy covers hot?

No. In fact, unlike PUL, wool is naturally temperature regulating. All the air pockets between the knitted stitches let air flow in and out, keeping you cool when it's hot. The evaporation of moisture also helps keep the wearer cool, like the cooling effect of splashing water on your skin and letting it evaporate. And when it's cold, those same air pockets will hold the warmer air close to your skin, keeping you warm!

How do I measure for a wool nappy soaker

See my wool nappy cover measuring guide on my Wool Nappy Soakers page.

Can I use wool outside the house?

Yes, but you will need to take a spare cover (either another soaker or a PUL wrap) with you in case it starts leaking. For this reason, it can be easier just to use wool at home, especially to start with. Although in my experience, I always had to take spare clothing and wraps with me wherever I went anyway so it didn't make a lot of difference, except that wool is perhaps a little more bulky!

Is wool more expensive?

The amount of wool needed for a baby sized soaker is not expensive, but even a newborn wool cover will take around 3.5 hours to knit (and an adult one up to around 30 hours!), so unless you can knit it yourself you'll have to pay for a skilled knitter's time. Soakers made from already knitted or felted wool sewn together are quicker to make and therefore tend to be cheaper.

If you're a knitter yourself, though, knitting your own soakers can be a very affordable way to waterproof your nappies! You can use my Any Size Wool Soaker pattern to knit a soaker in any size from newborn to adult, using any weight of wool.

Do you feel ready to start using wool?

Take the plunge into a world of soft, squishy, natural wool covers!

And please do comment below if you have any questions! I'm always glad to help, if I can!


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