Fabrics used in MCNs - why is that important?

Let's talk nappy fabrics today!

Something that most of us don't think much about when first looking at buying cloth nappies but is actually quite important!

Why is that important??

Because the type of fabric used in reusable nappies will determine how much the nappy absorbs, how fast/slow it absorbs, how the nappy holds on to the moisture, how the nappy withstands regular washing (wear and tear), how waterproof the nappy is, how it fits with your environmental beliefs (eg synthetic vs natural fibres); to name a few.



Let's start here as that is the place with the least options.

The outer layer needs to provide waterproofness or more likely water resistance. Because tbh nothing is fully waterproof unless it is a thick plastic sheet that doesn't breathe...and we wouldn't want that wrapped around our babies!

All nappies will resist to moisture but the amount and for how long will vary depending on the material, thickness and of course what you have inside absorbing the moisture in the first place!

Wool covers

The most natural cover fabric you can use is wool. Many MCN users are very satisfied with wool covers:

  • they are a very affordable option
  • don't need washing as often due to wool's natural resistance to odour
  • dry quickly
  • are popular as night nappy covers for heavy wetters

But they do require some maintenance with re-lanolising from time to time to keep their water resistance properties and gentle washing to keep their shape.

PUL - Polyurethane Laminate

A thin, synthetic, breathable material that keeps moisture from escaping while allowing air circulation.

There are actually 2 types of "PUL", they are both the same thing, just made by a different process:

  1. PUL (TPU - Thermoplastic Polyurethane) is a type of polyurethane film that is heat-bonded to a fabric. TPU is flexible, stretchy, and breathable while offering waterproof protection and good durability. Since 2010, most nappy covers use TPU PUL.
  2. PUL (PUR - Polyurethane Laminate using glue/solvents) is a polyester knit fabric that has been laminated with a thin layer of polyurethane on one side using glues or solvents. A very durable fabric that can withstand high washing temperature, we're talking 90°C! But of course, uses solvents during manufacture.

Polyester Fleece

Polyester fleece is a synthetic fabric, not inherently waterproof but it is often used as a water-resistant fabric in cloth nappies.


Real Nappies Snug Wraps are made of TPU PUL (heat bonded) and are DOUBLE LAYERED for extra water resistance and a soft feel on both sides of the cover.


  to look at the Snug Wraps.


NAPPY INSERTS (the inside bits)

Now this is the other part that is important to understand for your nappies to work as intended and especially to compare buying nappies as the nappies will all come with different inserts.


Bamboo: A synthetic fabric called Viscose derived from bamboo, with a high level of absorption so is great at holding liquid. Beware of greenwashing statements about this fabric as most inserts will state bamboo but there is really nothing left of the bamboo as it has been turned to Viscose. There are two manufacturing methods of bamboo fibres: a Chemical Process or a Mechanical Process. The majority of the bamboo fibres are produced by the viscose rayon chemical processing method. Which is cheap to produce but has some environmental downsides. Ensure that you are getting a high-quality bamboo fabric, make sure that it is manufactured with a mechanical rather than a chemical process. Pure mechanically processed bamboo will feel quite rough and so is usually blended with other fibres for use in fabrics.

Cotton: A natural fabric with a high level of absorption. Cotton has been used for hundreds of years. It has a well known manufacturing process with many life cycle studies to back its lower environmental impact overall. This is why we love cotton at Real Nappies and our inserts are made of variation in thickness and weaving type of the cotton fibres.

Babies have worn cotton nappies for hundreds of years!

We also have certified Organic prefolds if you are worried about pesticides used during the growing of the cotton.


 to have a look at the inserts (prefolds, flats and 10-layer booster pads).


Fleece or microfleece: Not to be confused with microfibre, this is a polyester material that can be used next to the skin. Often found inside pocket nappies as the internal "stay dry" layer, and as reusable liners but is prone to collecting lint. It somewhat holds the moisture but lets it through quicker to other parts of the nappy. However, be mindful that polyester sheds during washing and end up as microplastics in the environment. For this reason, we do not sell fleece products.


Hemp: Natural fibre made from the hemp plant. It is very popular in cloth nappy use because of its durability, absorbency and natural anti-microbial properties. It is a little slower at absorbing moisture. Inserts made of hemp work well in conjunction with a natural fabric like the Real Nappies cotton prefolds: place the hemp insert inside or under the prefold to boost absorbency.


Microfibre: Microfibre is a fast absorbing synthetic polyamide fibre that is often found in pocket nappy systems. It is cheap to manufacture, absorbs moisture very quickly and can hold up a good amount of moisture but it is prone to compression leaks, so as soon as pressure is applied the urine easily comes back out the of insert like a sponge. It should not be used directly next to the skin as the tiny fibres can cause irritation. If you choose to us microfibre, it works well in conjunction with a natural fabric like the Real Nappies cotton prefolds: place the microfibre inside the prefold to catch any compression leaks. However, be mindful that microfibre sheds during washing and end up as microplastics in the environment. For this reason, we do not sell microfibre products.

(Image courtesy of Clean Cloth Nappies)


Suedecloth: A stay-dry material often found on the inside of nappies. This is a synthetic polyester material and has no relation to animal based suede. Suedecloth sheds during washing and end up as microplastics in the environment. For this reason, we do not sell suedecloth products.

Terry Nappy or Terry Squares: The Terry Nappy is the traditional nappy that your mother or grandmother would have used! A square piece of terry cotton that can be folded in a manner of ways and fixed with a nappy fastener such as our Snappis. They are inexpensive, easy to find and make yourself, extremely versatile and quick to dry. A good alternative to the prefolds in the newborn or infant days.

Unbleached: Unbleached fibres are those which have not gone through a chemical bleaching process. They usually retain more of the fibre's natural oils and waxes, so may need washing more times than bleached fibres before they reach full absorbency but have undergone less processing and are softer on skin.


ABSORBENCY CAPACITY AND SPEED ... And why we love Cotton at Real Nappies

An important factor in choosing what type of fabric insert inside the nappy, to use at different stages or parts of the day is how fast the fabric absorbs and how much. Especially important when babies reach a stage where they are holding their wees for longer and letting go of a bigger amount, all at once, instead of small regular amounts.



Often cheaper nappies will come with a microfibre insert to keep the price down and be attractive to new parents. Nappies with microfibre or charcoal bamboo inserts will work ok when baby is small. But comes the 3-4+ months old mark and leaks will start occurring as the inserts are not absorbent enough for the amount baby is releasing and not able to contain the urine.

And that is when new cloth parents will get leaks, become frustrated and start thinking about giving up on reusable nappies.

Around the 9+ months mark, "flooding" can occur inside the nappy when baby releases urine fast and in one go instead of small amounts often. That is when an insert with FAST absorbency will be helpful to bring the urine more quickly into the high capacity insert.

A few figures about insert capacity:

  • typical cotton muslin flat 70x75cm 150g
  • 3-layer bamboo insert 115g
  • Bamboo viscose trifold inserts 180g
  • typical snake insert 145g
  • Real Nappies newborn prefold 110g
  • Real Nappies infant prefold 200g
  • Real Nappies crawler prefold 290g

Pairing a fast absorbent insert closest to baby's skin with a high capacity insert underneath will prevent leaks from happening. Even things like face washers can be a cheap and easy way to boost the nappy and provide that fast absorbency. Just remember, microfibre causes skin irritation so do not put it directly against baby's skin.

Once you have a look at the 2 pictures above, it becomes pretty clear why we love Cotton at Real Nappies!

Cotton is a natural fibre and pretty good all-round workhorse in the world of cloth nappies. It has quite a high absorbency capacity but also not bad on speed of absorption. It is a good type of insert to have in your nappy and the other types of fabrics can be added around it if needed.


Remember this:

  • the type, number and size of insert needed in a reusable nappy will change over time as baby grows and urine output changes. This can vary greatly from child to child. Keep calm and carry on! If you start having absorbency issues, look at the inserts you already have, try more absorbency and the right type following the guides above.
  • pairing a fast absorbent insert closest to baby's skin with a high capacity insert underneath will prevent leaks from happening.