Polyester is a synthetic fibre made from long chains of molecules (polymers). It’s naturally hydrophobic, which means it doesn’t absorb much water. But that doesn’t automatically make polyester waterproof.
In most real-world uses, untreated polyester is best described as water-resistant. It can repel light moisture, dries quickly, and handles everyday spills well — but sustained rain, pressure, or pooling water can still seep through the weave and stitching.
If you’re choosing a fabric for outdoor or spill-prone seating, it helps to know exactly what “waterproof” means and what to look for on product specs. Below is a practical guide (with plain-English explanations) to help you choose the right material for a bean bag and similar soft furnishings.
Waterproof vs water-resistant: the difference matters
These terms get mixed up constantly, but they’re not the same.
Water-resistant (most polyester fabrics)
- Repels light rain, splashes, and minor spills
- Moisture tends to bead on the surface (especially if treated)
- Can soak through under pressure or after long exposure
Waterproof (polyester with the right build)
- Prevents water from passing through the fabric layer
- Typically requires a coating, laminate, or membrane
- Seams and zips must also be managed to reduce leakage
So, when someone asks “Is polyester waterproof?”, the most accurate answer is: polyester can be made waterproof, but polyester on its own is usually only water-resistant.
Is 100% polyester waterproof?
A fabric labelled “100% polyester” tells you the fibre content, not the performance. Two fabrics can both be 100% polyester and behave completely differently in rain.
What changes the result is:
- Weave tightness (tighter weaves slow water penetration)
- Coatings (PU or PVC coatings are common)
- Laminates/membranes (thin layers bonded to the fabric)
- Seams and stitching (needle holes create entry points for water)
In other words, polyester fibre is water-resistant by nature, but waterproofing is achieved by engineering the fabric system around it.
Why polyester repels water in the first place
Polyester has low moisture absorption compared with natural fibres like cotton. Water tends to sit on the surface rather than soaking deep into the yarns, which is why polyester:
- Feels practical for everyday furniture
- Dries faster after spills
- Is commonly used for outdoor cushions and covers
That said, water can still pass through polyester if the weave is open enough or if pressure forces water through (for example, someone sitting on a damp seat).
What makes polyester genuinely waterproof?
If you want a polyester fabric that behaves like a true “hose it off” surface, look for one of the following constructions.
1) PU-coated polyester (polyurethane coating)
PU coatings add a thin waterproof layer to the back (or sometimes both sides) of the fabric. This is one of the most common approaches for outdoor soft furnishings because it balances protection with comfort and flexibility.
- Good waterproofing when new
- Often softer and less “plasticky” than PVC
- Can wear down over time depending on use and UV exposure
Many outdoor seating products use PU-coated polyester because it resists light rain, splashes, and typical backyard life.
2) PVC-coated polyester
PVC-coated polyester is more like a waterproof tarp material. It’s extremely water-resistant, wipe-clean, and durable, but it can feel stiffer and less breathable.
- Very strong waterproof barrier
- Excellent for harsh outdoor exposure
- Less breathable and can feel firmer
3) Laminated polyester (membrane or film layer)
Laminates bond a membrane to the polyester fabric, creating a consistent barrier layer. Some laminates aim to retain flexibility and reduce cracking over time.
- Reliable waterproof performance if the laminate remains intact
- Common in technical outdoor products
- Performance depends on laminate quality and seam construction
Don’t ignore seams: stitching is often the weak point
Even if the fabric itself is waterproof, seams are a common place for water ingress. Stitching creates tiny holes, and under pressure or pooling water, moisture can seep through those points.
For higher waterproof performance, manufacturers may use:
- Seam taping (common in jackets, less common in furniture)
- Heat sealing or welded seams (more common in PVC constructions)
- Design features that limit seam exposure on top surfaces
For outdoor bean bags, practical waterproofing usually comes down to a combination of a coated polyester fabric plus smart construction choices.
What’s the best fabric for a bean bag that might get wet?
Different fabrics suit different environments. Here’s a practical comparison for bean bag use.
Polyester (especially coated)
- Great balance of comfort and moisture resistance
- Quick drying and fade resistant
- Best when it’s PU- or PVC-coated for outdoor use
Nylon
- Very strong and abrasion resistant
- Often used in outdoor gear
- Can be made waterproof with coatings, similar to polyester
Cotton
- Soft and breathable
- Absorbs water and stains easily
- Better suited to indoor spaces
Vinyl
- Wipe-clean and inherently waterproof
- Ideal for heavy spill zones
- Less “cosy” feel compared with woven fabrics
If you’re shopping specifically for outdoor seating, purpose-built outdoor bean bags are designed around coated fabrics and construction features that handle weather and spills far better than indoor styles.
How to clean polyester bean bags without ruining the coating
Cleaning depends on whether the polyester has a coating or laminate.
- Wipe-clean first: Use a damp cloth with mild soap for most spills.
- Avoid harsh chemicals: Strong solvents can break down waterproof coatings.
- Skip machine washing unless the care label allows it: Some coatings can crack or peel with aggressive washing.
- Dry properly: Air dry fully to avoid trapped moisture in seams and zips.
If you’re after general care tips, this guide on how to clean a bean bag chair is a good starting point for everyday maintenance.
Will polyester stay waterproof forever?
Waterproof performance isn’t always permanent. Over time, coatings can wear due to:
- UV exposure (Australian sun is particularly harsh)
- Frequent abrasion (dragging, rough surfaces)
- Repeated cleaning with strong products
- Salt/chlorine exposure near pools
If a product relies on a surface treatment (like a water-repellent finish), that finish can also reduce over time and may need re-application.
So, is polyester fabric waterproof?
Untreated polyester is generally water-resistant, not fully waterproof. It repels light moisture, dries quickly, and performs well for everyday furniture use. For true waterproofing, polyester typically needs a PU or PVC coating, a laminate/membrane, and well-considered construction (especially around seams and zips).
If you’re choosing a bean bag for outdoor living, poolside areas, or spill-heavy family zones, focus on the fabric specification (coated/laminated), not just the fibre content. That’s where the real waterproof performance comes from.
