Waterproof, water-resistant, water-repellent – three words, three completely different things

In everyday speech the terms get used interchangeably, but in the world of textiles they mean quite different things:

The key insight: waterproof and comfortable are practically mutually exclusive when it comes to a mattress. Because every seam, every zip, is a potential entry point. A genuinely waterproof cover would have to be coated and welded – like an air mattress. And it would feel exactly like one, too.

What you expect – and what actually happens

What you expect: a waterproof mattress stays outside all summer, rain pours down on it, and the next day everything's as good as new.

What actually happens: with a coated cover, water pools on the surface instead of running off. As soon as you lie down, sweat moisture builds up between your skin and the coating with nowhere to escape. And if water does get in at some point – through the zip, a seam, or condensation from temperature swings – it stays in, because the "waterproof" cover won't let it back out either. The result is exactly the mouldy mattress you were trying to avoid in the first place.

What actually works: a cover that physically can't absorb water, combined with shape-stable foam and a construction that releases moisture quickly. Olefin fabric absorbs less than 0.1 percent moisture – the lowest figure of any common textile fibre. Rain beads off and runs straight through instead of staying in the fibre; mould finds no breeding ground. The background on the fibre itself is in our guide What is olefin?.

Outdoor mattress cover: is a waterproof cover over your old mattress enough?

This is the second most common question in this category – and the idea is understandable: the old guest mattress is sitting in the basement, throw a weatherproof cover over it, and you've got yourself a garden mattress. From a workshop perspective, we'd advise against it, for three reasons:

1. The wrong core. Indoor mattresses are made of cold foam, memory foam or pocket springs with fleece layers – all materials that absorb and hold onto moisture. The moment the cover fails at even one point, the core soaks right through and won't dry out for weeks.

2. The cover is never actually sealed. A cover with a zip is, by definition, not waterproof. Without a zip, you can no longer get to the core – and can't wash the cover either.

3. Condensation. Even if no rain gets in: on warm days and cool nights, humidity condenses inside a sealed cover – directly onto a core that soaks it up eagerly.

That's why an outdoor mattress is engineered as a whole. Our Marocco outdoor mattress combines mattress-grade PUR foam that stays shape-stable even under daily use with a cover made from 100% olefin – removable via zip and washable, so sunscreen and pollen end up in the machine instead of in the mattress. If moisture does get in during continuous rain, it dries back out once the mattress is stood upright, because neither the fibre nor the foam holds onto it.

Custom garden mattress: what size and thickness?

Whether you call it a garden mattress, an outdoor mattress or a lounger mattress – it all means the same thing: a lying surface for outdoors with real mattress thickness. We make the Marocco from 8 centimetres thick in any size up to 200 × 200 centimetres, with no surcharge for custom sizes. The three most frequently ordered formats:

120 × 200 cm – the pallet size. Fits lengthwise across two Euro pallets and is the most popular format for pallet lounges and narrow daybeds.

140 × 200 cm – the double-bed size for outdoor beds and Bali daybeds, for two people to lie on.

200 × 200 cm – the pool island. For built-in lounging platforms and lounge podiums; from 135 centimetres in width we add a precise centre seam, because our premium fabric is produced in a standard width of 140 centimetres.

Every common size, along with its use case and matching thickness, is listed in the complete size chart; if you want to use the mattress for sleeping outdoors, our guide Outdoor daybed mattresses for real sleeping comfort covers the comfort criteria. As a neck support, the Milano bolster cushion in the same olefin completes the mattress.

The rain routine, straight from the workshop

Here's how a water-repellent outdoor mattress stays in shape for years – four rules we give every customer:

Short shower: leave it be. Water beads off, and the surface is dry again after half an hour of sun.

Continuous rain or a storm: stand the mattress upright against a wall or bring it under cover. Not because it would take damage – but so it never soaks through in the first place and is ready to use again the very next morning.

After the pool: wet swimwear leaves behind chlorine or salt residue that, under UV light, wears down the fabric over time. Rinse briefly with clear water and let it dry upright – the full pool routine is in our guide Pool cushions: waterproof and chlorine-resistant.

Out of use for a while: store it dry and protected – also against pollen and leaves. How to put cushions away for winter and treat stains in detail is explained in our guide Caring for outdoor cushions the right way.

For an overview of every type of made-to-measure cushion – from sun loungers to XXL mattresses – see our comprehensive guide Custom Outdoor Cushions. And if you want to put the fabric through its own water-droplet test before ordering: free fabric samples are available to order, delivered to your door.

Frequently asked questions about waterproof outdoor mattresses