100% Cotton Dust Mite Mattress Protector & Encasement — 35cm

A 100% cotton dust mite mattress encasement for mattresses up to 35cm deep — tightly-woven cotton fabric with an independently-tested pore size of 2.8 microns. OEKO-TEX Standard 100 certified, full zippered closure with Velcro lock flap. Available Single, King Single, Double, Queen, King, and Super King.

Stock note: King size is currently on backorder and expected back in stock on 30 May. Orders containing King size will be shipped when stock arrives. If you've ordered other sizes alongside King, those will ship first and the King size will follow at no extra charge.

At a glance

• Fabric: 100% cotton, tightly woven upland cotton
• Pore size: 2.8 microns at maximum distribution — independently tested by capillary flow porometry (Galwick fluid).
• Seams: Enclosed binding for continuous barrier integrity
• Closure: Three-sided U-shape zipper with Velcro lock flap to prevent accidental opening
• Coverage: Encloses all six sides of the mattress
• Certification: OEKO-TEX Standard 100 (tested for over 100 substances of concern)
• Mattress depth: Fits mattresses 25–35cm deep
• Care: Machine washable, tumble-dry on medium heat
• Quality: Manufacturer-backed against defects

What this product is

A full mattress encasement that seals your mattress inside a tightly-woven cotton barrier on all six sides — can be used in homes where dust mite allergens are a concern.

• Why this matters for dust mite allergens. Dust mite allergens are carried by fecal pellets and body fragments that typically measure 10 to 40 microns. Mattresses are one of the most concentrated dust mite allergen reservoirs in a bed. This encasement's 2.8-micron weave traps these allergen-carrying particles inside the mattress.
• Use alongside pillow and quilt encasements. A mattress encasement covers one allergen reservoir of three. Many households fit all three together as part of a broader dust mite allergen reduction approach.
• How it fits. Slide your mattress in through the three-sided U-shape zipper, close the zip, fold the Velcro flap to seal it. Your normal mattress protector goes on top to take daily wear.

Who this is for

This encasement is commonly chosen by:

• Households setting up dust mite barrier bedding across the main bed layers (mattress, pillow, quilt)
• People setting up an allergen-aware bedroom alongside pillow and quilt encasements
• People who prefer 100% cotton bedding without polyurethane laminates or synthetic fibres
• Households who want a fully sealed mattress encasement that also functions as a barrier to bed bugs

It's probably not the right fit if:

• Your mattress is shallower than 25cm — see our 25cm cotton mattress encasement instead
• You need a cot-size mattress protector — see our cot mattress protector instead
• You need waterproof protection — see our waterproof mattress encasement instead

What the fabric does

Dust mite allergens are carried by fecal pellets and body fragments that typically measure 10 to 40 microns. This fabric tests at 2.8 microns at maximum distribution, well below that.

• Tightly-woven cotton barrier. Particles inside your mattress stay inside, rather than passing through to the air around you.
• Enclosed binding seams. Fabric edges are sealed within a binding strip so the barrier extends from corner to corner without a gap.
• Velcro-locked zipper. A three-sided U-shape zipper covered by a Velcro flap, which stops the zip working open over time and seals the closure end where the zipper pull sits — a common entry point in cheaper encasements.
• Breathable. Woven cotton, not laminated plastic — no heat trap, no "crinkle" feel. Washes and dries like normal bedding.

Test method: capillary flow porometry using Galwick fluid, conducted by an independent third-party lab.

Sizing

This encasement is for mattresses 25–35cm deep. Cotton has minimal stretch, so order based on your mattress's actual dimensions. Encasements are sized slightly larger to allow for normal wash shrinkage.

Will it fit my mattress? Measure your mattress depth from the top surface down to where it rests on the base. If you're between 25cm and 35cm, this 35cm version is the right choice. Between 35cm and 37cm, it's borderline — the encasement may compress 1–2cm but should still fit. Over 37cm, this size isn't suitable; contact us for custom sizing.

How to fit it

For a mattress on a slatted or solid base:

1. Strip the mattress completely and vacuum the surface to remove existing dust and allergens.
2. Stand the mattress on its side, leaning against a wall if needed.
3. Unzip the encasement fully and slide it over the mattress from the top.
4. Lay the mattress flat on the bed, then close the zipper around the three sides.
5. Fold the Velcro flap over the zipper to seal the closure.
6. Place a standard mattress protector on top to absorb daily wear.

For a mattress on a bed base or box spring: remove the base legs or wheels first. Slide the encasement over the base, close the zipper, then make small incisions where each leg/wheel attaches and screw them back in firmly through the encasement fabric — this seals the encasement to the base around each leg.

Care

• Before first use: Wash the encasement twice before fitting. This removes any production residues and is recommended by the manufacturer.
• Wash: Machine wash in warm or hot water. 60°C is the temperature most commonly cited for dust mite reduction in bedding, where the care label allows.
• Dry: Tumble dry on medium heat or air dry. Avoid high heat — repeated hot drying can shrink cotton.
• Frequency: Every 6 months is generally sufficient when a standard mattress protector sits on top to absorb daily wear. The decorative protector above gets washed weekly with your bed linen; the encasement underneath stays cleaner for longer.
• Avoid: Bleach, fabric softeners, dry cleaning, and ironing.

Certification and testing

• OEKO-TEX Standard 100 — an independent global certification confirming the textile (including thread, zipper, and fabric) has been tested for over 100 substances of concern.
• Independent fabric testing — pore size of 2.8 microns at maximum distribution, measured by capillary flow porometry using Galwick fluid by a third-party lab.

We don't make claims that the product cures, treats, or prevents allergies, asthma, or any medical condition. What we describe is the fabric's measurable physical properties as a barrier against fine particles.

Pairs well with

For a complete bedding setup, customers commonly pair this with:

• Dust mite pillow protectors — one per pillow
• Cotton dust mite quilt encasement — covers the doona
• Mattress Mate slip-on protector — a washable top layer that goes over this encasement

A complete allergen-aware bedroom uses all three barrier layers — mattress, pillow, and quilt. For more on setting this up, see our guide to dust mite barrier bedding.

Frequently asked questions

What's the difference between a mattress protector and a mattress encasement?

A standard mattress protector covers only the top of the mattress, fitted-sheet style, with elasticated edges. It's used to protect against spills and stains, but it doesn't form a barrier against dust mite particles because the sides and base of the mattress remain exposed. A mattress encasement — like this product — fully encloses all six sides of the mattress, with a three-sided U-shape zipper that closes to seal the mattress inside.

Is this hypoallergenic?

The word "hypoallergenic" doesn't have a defined Australian standard, so we're cautious about applying it as a product claim. What we can tell you is what the fabric measurably does: it's tightly-woven 100% cotton with a pore size of 2.8 microns, OEKO-TEX Standard 100 certified, with enclosed binding seams and a Velcro-locked zipper closure.

What pore size is needed to limit dust mite allergens?

Dust mite allergen particles typically measure 10–40 microns. Anything below about 10 microns will limit them. This product's fabric tests at 2.8 microns at maximum distribution — well below that threshold.

Why 100% cotton rather than polyester or microfibre?

Cotton is breathable, washable at higher temperatures, and feels like normal bedding. Polyester or polyurethane-backed encasements can feel hot or noisy. The trade-off is that cotton encasements typically cost more and aren't waterproof.

Will it make me hot or sweaty at night?

No — it's 100% cotton with no plastic or polyurethane backing, so it breathes naturally and doesn't trap heat the way plastic-coated protectors do.

Is it noisy?

No. Plastic-backed protectors crinkle when you move; this is fabric on both sides and is silent.

Does it block bed bugs?

The 2.8-micron weave is too tight for bed bugs or their eggs to pass through, and the Velcro-locked zipper closure has no gaps. We describe this product primarily for dust mite use because that's the most common application, but the same physical barrier applies to bed bugs.

Someone in my household has eczema or asthma — what can you tell me about the fabric?

We can describe what the fabric does — it's a tightly-woven 100% cotton barrier with enclosed binding seams — but we don't make claims about how that affects any medical condition. If you have eczema, asthma, or another diagnosed condition, please speak with your GP or allergist.

How often should I wash it?

Every 6 months is generally sufficient when a standard mattress protector sits on top to absorb daily wear.

What temperature should I wash it at?

60°C is the temperature most commonly cited for dust mite reduction in bedding, where the care label allows. Cooler washing still removes a high proportion of allergens.

Can I tumble dry it?

Yes, on medium heat. Avoid high heat — repeated hot drying can shrink cotton over time.

What is OEKO-TEX Standard 100?

OEKO-TEX Standard 100 is a global independent certification that tests every component of a textile product (fabric, thread, zipper, prints) for over 100 substances of concern.

My mattress is deeper than 35cm. What do I do?

If your mattress is between 35–37cm deep, this encasement should still fit but may compress slightly. Above 37cm, this size isn't suitable — contact us for custom sizing options.

Will it fit a memory foam or pillow-top mattress?

Yes, as long as the total depth is between 25cm and 35cm. Measure from the top surface down to where the mattress meets the base.