Is Polyester Waterproof?

Is Polyester Waterproof?

Untreated polyester is water-resistant but not waterproof. The fibre absorbs very little water and dries fast, but under steady rain or pressure, water gets through the gaps between the yarns. Polyester only becomes waterproof when it is coated or laminated, for example with PU, PVC or TPU, and its seams are sealed.

Polyester is a popular material commonly used in the production of various clothing items, outdoor gear, and even household items like bean bags. But one question that often arises is whether polyester fabric by the metre is waterproof or not. This guide covers what the labels mean, when polyester leaks, whether a polyester jacket will keep you dry, and how to proof and sew waterproof polyester at home.

To answer this question, it's important to understand that there is a difference between waterproof and water-resistant fabrics. While both have the ability to repel water to some extent, waterproof fabrics are designed to completely prevent water from penetrating through them, even in the most severe conditions. On the other hand, water-resistant fabrics are able to resist water to a certain degree, but may eventually allow water to seep through with prolonged exposure or heavy rains.

Polyester is not naturally waterproof. However, through various manufacturing processes and treatments, polyester can be made water-resistant or even waterproof. One common method used to achieve water resistance is the application of a special coating to the polyester fabric's surface. This coating creates a protective layer that repels water, preventing it from being absorbed by the fabric.

Moreover, polyester can also be laminated with a layer of polyurethane or a polyurethane membrane to enhance its waterproof abilities. This lamination process involves bonding a thin layer of polyurethane to the polyester fabric, creating a barrier that effectively blocks water from passing through. This process is commonly used in the production of waterproof jackets, rain gear, and winter coats, allowing them to provide reliable protection against rain, snow, and other wet conditions. If you want a fabric that is already proofed, start with our waterproof fabric rather than plain polyester.

This post sticks to water and weather. For the basics, read our guide to what polyester fabric is and how it feels.

Water-resistant, water-repellent or waterproof: what the labels mean

Fabric listings and garment labels use these words loosely, but they describe quite different levels of protection. Here is how they usually apply to polyester.

Label/finish	What it does	Good for
Untreated polyester	Resists light splashes and dries fast, but lets water through in steady rain	Linings, everyday wear
Water-repellent / DWR finish	Makes water bead and roll off the surface; wears off with washing and needs re-proofing	Showerproof jackets, bags
PU-coated polyester	A polyurethane coating on the back blocks water	Tote bags, rain covers, simple rainwear
PU or TPU laminate / membrane	Waterproof, and can be breathable depending on the membrane	Rainwear, outdoor gear, nappy covers
PVC-coated polyester	Fully waterproof and heavy; does not breathe	Tablecloths, bean bags, covers

The fabric is only half the job. Every stitch punches a hole through the coating, and water will find its way through those holes. That is why proper waterproofs have sealed or taped seams, where a strip of waterproof tape or a liquid sealant covers the stitching on the inside. A coated fabric with open seams will still leak along the seam lines.

What is hydrostatic head?

Manufacturers sometimes state a hydrostatic head in millimetres. It describes how tall a column of water the fabric can hold back before water starts to come through. A higher number means the fabric can take more water pressure before it leaks. Not every listing gives one, but where two fabrics do, compare the figures to see which offers more protection.

Does Polyester Absorb Water?

Polyester, a popular synthetic fabric known for its durability and versatility, does not absorb water like natural fibres such as cotton or wool. This is because polyester is made from long-chain polymers that are hydrophobic, meaning they naturally repel water. The fibre itself takes up very little moisture, although water can still pass through the spaces between the yarns of an untreated fabric.

The hydrophobic nature of polyester is one of its key advantages. Unlike natural fibres that can become heavy and wet when exposed to water, polyester remains lightweight and dries quickly. This makes it an ideal choice for outdoor clothing and gear, where staying dry and comfortable is essential.

While polyester itself is not absorbent, it can still become wet when water is present. This is because water can cling to the surface of polyester fabric, especially if it has not been treated with any water-resistant finishes or coatings. However, the water is not absorbed into the fibres themselves; it sits on and between them, and either beads and rolls off or evaporates.

A water-repellent finish improves this further, and a polyurethane coating or laminate (covered above) stops water passing through altogether, which suits harsher weather. Note that the level of water resistance or waterproofing of polyester fabrics can vary depending on the quality of the fabric and the specific treatment it has undergone. It is always advisable to check the product's specifications or care instructions to understand its water resistance capabilities.

Can polyester get wet? What happens in the rain

Yes. In a light shower, untreated polyester gets wet on the surface and much of the water runs off. In steady rain, the water works through the gaps in the weave or knit and you will feel it on your skin. Because the fibre holds so little water (see the section above), a wet polyester garment stays fairly light and dries much faster than cotton, which soaks up water and stays heavy.

Wet gear still needs drying properly. Hang it up straight away rather than leaving it bundled in a bag, and make sure it is completely dry before you put it away. Damp fabric stored in a cupboard can grow mildew on dirt and finishes, even if polyester itself resists it; our guide on how to get mould out of fabric helps if it is too late.

Types of Waterproof Polyester Fabrics

Polyester is widely used for outdoor clothing and gear, but not all polyester fabrics handle water in the same way. Here are some of the different types of waterproof and water-resistant polyester fabrics available.

1. PVC-Coated Polyester: This type of polyester fabric is coated with polyvinyl chloride (PVC), which creates a waterproof barrier. PVC-coated polyester is highly durable and can withstand harsh weather conditions, making it commonly used for products like bean bags and rain gear.

2. Polyurethane Laminate (PUL): Polyester fabric can also be laminated with a thin layer of polyurethane, creating a waterproof laminate barrier. PUL fabric is flexible and waterproof, with some breathability, making it a good choice for nappy covers, wet bags and outdoor gear like backpacks and tents.

3. TPU-Coated Polyester: Thermoplastic Polyurethane (TPU) is another popular coating used on polyester fabric to make it waterproof. TPU provides excellent abrasion resistance, flexibility, and waterproofing, making it suitable for outdoor clothing and gear like jackets and waterproof trousers.

4. Moisture-Wicking Polyester: While not waterproof, moisture-wicking polyester fabrics are designed to keep moisture away from the skin. These fabrics are specifically engineered to pull sweat away from the body, keeping you dry and comfortable during physical activities.

5. Recycled Polyester with Water-Resistant Finish: In recent years, the demand for sustainable and eco-friendly materials has led to the development of recycled polyester fabrics with water-resistant finishes. These fabrics offer water resistance while making use of recycled material.

Is a polyester jacket waterproof?

Most plain polyester jackets are showerproof at best. They will shrug off a short drizzle, especially when new and treated with a water-repellent finish, but they will wet through in a long walk in steady rain.

To tell whether a polyester jacket is genuinely waterproof, check the label and the listing for:

• the word "waterproof", not just "water-resistant" or "showerproof"
• a membrane or laminate, often described as a 2-layer, 2.5-layer or 3-layer construction
• taped or sealed seams
• a stated hydrostatic head figure

Polyester fleece and softshell jackets are not waterproof. Fleece is a warm, open knit that lets water straight through, and softshell is usually a stretchy woven with a water-repellent finish, made to breathe rather than to keep out heavy rain.

There is also wet weather on the inside to think about. Your body gives off moisture all the time, and more when you are active. A non-breathable coating such as PVC or a basic PU coating stops that moisture escaping, so it condenses on the inside of the jacket. You can end up damp with sweat even though no rain has come through. Breathable membranes reduce this, and vents, mesh linings and a looser fit help too.

Nylon has been long used as an alternative to Polyester.

Polyester vs. Nylon

Polyester and nylon are two popular synthetic materials used in the textile industry. Both fabrics have their own unique characteristics, making them suitable for various applications. Here are the key differences between polyester and nylon to help you decide which fabric is the right choice for your needs.

One of the primary differences between polyester and nylon is their durability. Nylon is known for its exceptional strength and resilience, making it an ideal choice for products that undergo heavy use or require high tensile strength. It is commonly used in products such as backpacks, luggage, and outdoor gear. On the other hand, polyester is also durable but tends to be less strong than nylon. However, polyester is often praised for its excellent resistance to fading, stretching, and shrinking, which makes it a preferred choice for everyday clothing and household items.

Another notable difference between polyester and nylon is their moisture absorption characteristics. Polyester has low moisture absorption properties and is quick-drying, making it ideal for activewear and clothing worn during physical activities. Nylon absorbs more water than polyester and dries more slowly. Nylon is used for outdoor gear and wet-weather clothing because it is strong and abrasion-resistant, not because of how it handles water. In both fibres, waterproofing comes from the coating or membrane, not from the fibre itself.

For breathability, both are low-absorbency synthetics, so neither breathes like cotton or linen. Polyester performance knits are engineered to wick sweat along the fibres so it evaporates quickly, which is why sports tops so often use them. Beyond that, breathability depends mainly on the weave or knit and on any coating: an open knit breathes more than a dense woven, and coated fabrics breathe less than uncoated ones. This is something to consider when choosing fabric for clothing items intended for hot and humid weather conditions.

In terms of price, polyester is generally more affordable than nylon. Nylon is deemed a higher-end fabric due to its strength and durability. However, the price difference may vary depending on brand, quality, and specific application factors.

Both polyester and nylon are versatile fabrics that are widely used in the textile industry. Polyester is often favoured for its resistance to fading, stretching, and shrinking, making it a popular choice for everyday clothing and household items. Nylon, on the other hand, is prized for its strength, durability and abrasion resistance, making it a go-to fabric for outdoor gear and high-performance applications, usually with a waterproof coating added.

Is Recycled Polyester Waterproof?

Recycled polyester is becoming increasingly popular due to its eco-friendly nature and the growing demand for sustainable textile options. But one question that often arises is whether recycled polyester is waterproof. The short answer: it behaves just like new polyester, so it is water-resistant, and only waterproof once it is coated or laminated.

When polyester is recycled, it is broken down into polyester pellets or chips, which are then spun into new fibres. During this process, additional chemicals and additives may be introduced to enhance the performance and characteristics of the recycled polyester.

As with new polyester, a water-resistant coating or finish is often applied to the finished fabric. It repels water and keeps the wearer dry in light rain or during short exposure to water.

Depending on the specific treatment applied to recycled polyester, the level of waterproofing varies. Some garments or products may have a light water-resistant coating, while others may have a more robust and durable treatment. The degree of waterproofing can also be influenced by factors such as the thickness and density of the fabric.

Water resistance is not the same as waterproofing. In heavy rain or prolonged exposure, water will eventually work through a treated recycled polyester, so for reliable protection manufacturers add a laminate or polyurethane membrane, exactly as they would with new polyester.

How to waterproof polyester fabric at home

You can improve how well polyester sheds water at home, but you cannot turn a plain, untreated fabric into a fully waterproof one with a spray.

• Wash-in or spray-on reproofers: these water-repellent treatments renew the beading effect on jackets and bags whose finish has worn off, or add some repellency to plain polyester. Follow the product instructions exactly, as methods and drying times vary. They make a fabric more water-repellent, not waterproof.
• Clean first: dirt and body oils stop repellent finishes working, so wash the item before reproofing. Our guide to washing fabric properly covers the basics.
• Seam sealer: a liquid seam sealant brushed over stitched seams on the inside stops water creeping through the needle holes.
• Test on a scrap first: some sprays can darken colours or change the feel of the fabric.
• Ventilate: spray outdoors or in a well-ventilated room, away from children and pets.

For a truly waterproof make, such as a rain cover or a wet bag, start with a coated or laminated fabric and seal the seams. Proofing at home is for maintaining repellency, not for creating waterproofing from scratch.

Sewing waterproof polyester fabric

Coated and laminated polyester is easy to sew once you allow for the fact that every hole is permanent.

• Pin only in the seam allowance: pins leave holes that will not close up, so keep them inside the seam allowance or use sewing clips instead. See which sewing pins to use for the options.
• Use a sharp needle: a sharp or microtex needle, from 70/10 for light fabrics up to 90/14 for heavier coated ones, pierces cleanly. Our machine needles range has both.
• Lengthen the stitch: set a slightly longer stitch of about 3mm. Short stitches perforate the coating like a tear-off line and weaken it.
• Use polyester thread: polyester all-purpose thread does not rot when it gets wet and has a little give.
• Seal the seams: apply seam tape or a liquid sealant over the stitching on the inside.
• Keep the iron off the coating: never iron the coated side. If you must press, use a low heat and a pressing cloth on the face side only.
• Stop it sticking: a walking foot or a non-stick (PTFE) foot glides over coated surfaces that would otherwise grab a standard presser foot.

A worked example: a simple waterproof tote bag takes about 1m of outer fabric. At £3/m that is £3; at £6/m, £6. These are indicative rates only, so check the current listing.

Waterproof alternatives to polyester

Waxed cotton: the traditional choice for country jackets and bags. Waxed cotton is cotton impregnated with wax, so it sheds rain well and can be re-waxed when it starts to wear thin. It is heavier than coated polyester and should not be machine washed.

PVC and faux leather: PVC leatherette has a solid plastic surface that water cannot pass through, which makes it useful for wipe-clean bags, seat covers and tablecloths. Like PVC-coated polyester, it does not breathe.

Nylon ripstop: a lightweight, strong nylon woven with a grid of thicker yarns that stops small tears spreading. It is usually coated for waterproofing and is popular for kites, stuff sacks and packable rainwear.

Is Polyester the Best Choice?

In conclusion, polyester and recycled polyester offer some water resistance on their own, and real waterproofing depends on the specific treatment applied to the fabric. Rather than choosing by fibre, choose by coating, membrane, seam sealing and weight. Polyester is a good base for coated waterproof fabrics because it absorbs so little water and holds its shape when wet. Nylon is the better choice when strength and low weight matter most.

Frequently asked questions

Is 100% polyester waterproof?

No. 100% polyester is water-resistant, not waterproof, unless it has been coated or laminated. The fibre absorbs very little water, but rain can pass through the gaps between the yarns in steady or heavy rain. Look for a PU, PVC or TPU coating, a membrane, and sealed seams if you need something that is genuinely waterproof.

Is polyester water-resistant?

Yes. Polyester fibres absorb very little water, so the fabric shrugs off light splashes and drizzle and dries quickly. That resistance has limits, though: under steady rain or pressure, water works through the weave or knit. A water-repellent finish improves it, and a coating or laminate is needed to make polyester fully waterproof.

Is polyester good in the rain?

Better than cotton, but plain polyester is still not enough for a long spell in steady rain. It will wet through, although it stays lighter and dries much faster than cotton. For proper rain protection, choose coated or laminated polyester with taped seams. For light showers, a polyester jacket with a water-repellent finish is usually fine.

Is a polyester jacket waterproof?

Usually not, unless the label says so. Most plain polyester jackets are showerproof at best. A genuinely waterproof jacket will say "waterproof" and usually mention a membrane or laminate, taped seams and sometimes a hydrostatic head figure. Polyester fleece and softshell jackets are not waterproof, as they are made to be warm and breathable instead.

How do you make polyester waterproof?

At home, you can only make it more water-repellent. A wash-in or spray-on reproofer, used according to the product instructions, renews or adds repellency, and seam sealer stops leaks along the stitching. To make something truly waterproof, sew it from a fabric that is already coated or laminated, such as PU-coated polyester, and seal the seams.

Does polyester dry faster than cotton?

Yes, much faster. Polyester fibres absorb very little water, so most of the moisture sits on the surface and evaporates quickly. Cotton fibres soak up water and hold on to it, so cotton feels heavy when wet and takes far longer to dry. That quick drying is one reason polyester is used so widely for sportswear and outdoor clothing.