If you’re choosing mattress protection for a child who wets the bed, you’ll quickly encounter two main formats: the fitted mattress protector and the encasement mattress protector. Both do the job — but they do it differently, and for heavy or frequent bedwetting, the distinction matters more than most product descriptions let on.
This guide covers how each type works, what the practical differences are, and which is likely to suit your situation.
What Is a Fitted Mattress Protector?
A fitted protector covers the top and sides of the mattress — much like a fitted sheet. It has elasticated corners that tuck underneath, leaving the base and underside of the mattress exposed.
Most waterproof fitted protectors use a polyurethane (PU) membrane laminated to a soft fabric surface. The membrane blocks liquid from passing through to the mattress, while the top layer feels relatively normal against a sheet.
Advantages of fitted protectors
- Easy to put on and take off — important when you’re changing bedding at 3am
- Machine washable and usually tumble-dryer safe
- Wide range of sizes, including cot, single, double and king
- Lower cost — typically £10–£30 depending on brand and quality
- Breathable options available, which can help with overnight comfort
Limitations of fitted protectors
- The sides and base of the mattress remain unprotected
- Heavy or pooling leaks can sometimes seep around the edges
- The elasticated underside can allow moisture to wick down if saturation is significant
- Does not protect against dust mites, allergens, or bed bugs entering the mattress from below
For most children with bedwetting, a good-quality fitted protector is entirely sufficient — especially when paired with an absorbent product. The exposed base is rarely relevant unless leaks are very heavy or the mattress is old and already damaged.
What Is an Encasement Mattress Protector?
An encasement completely surrounds the mattress on all six sides. It zips shut, sealing the mattress inside. No part of the mattress is exposed to the environment — or to liquid.
Encasements were originally developed as anti-allergy products (to block dust mite allergens) but are also widely used for moisture protection, particularly in healthcare and care settings.
Advantages of encasements
- Complete protection — liquid cannot reach any part of the mattress
- Prevents long-term odour build-up inside the mattress foam or springs
- Protects investment in an expensive mattress (memory foam, orthopaedic, etc.)
- Dual-purpose: also blocks allergens, dust mites and bed bugs
- Particularly useful where leaks are very heavy or nightly
Limitations of encasements
- More difficult to remove and refit — especially in the middle of the night
- Some feel noticeably crinkly or warm, depending on the material
- Tend to cost more — typically £20–£60 or more for quality options
- The zip can wear over time and become a weak point if not well made
- You still need a separate fitted layer on top for the child to sleep on comfortably
Fitted vs Encasement: The Core Practical Difference
The real-world difference comes down to how often leaks reach the mattress surface, and what you’re protecting against.
If your child wears an absorbent product overnight (pull-ups, taped briefs, boosted pads), the mattress protector is a secondary line of defence. A good fitted protector handles this well in most cases. The mattress base is rarely at risk.
If your child sleeps without a product, leaks heavily and frequently, or if you’ve had previous leaks reach and damage the mattress, an encasement offers meaningfully better long-term protection — particularly for foam mattresses, which are virtually impossible to dry properly once saturated.
Foam and memory foam mattresses cannot be dried from the inside out. Even a single significant leak that reaches the core can create a permanent odour. If the mattress cost over £200, an encasement pays for itself within a few incidents.
Which Should You Choose?
Choose a fitted protector if:
- Your child uses an absorbent product most or all nights
- Leaks are infrequent or moderate in volume
- You change bedding frequently and need something quick and easy
- The mattress is inexpensive or older and replacement isn’t a concern
- Budget is a factor — prioritise a good fitted protector over a cheap encasement
Choose an encasement if:
- Leaks are very heavy and happen most nights
- Your child sleeps without a product
- The mattress is expensive (memory foam, specialist or orthopaedic)
- You’re also managing allergies or sensitivities
- Previous leaks have already damaged a mattress and you want to avoid a repeat
Using both together
Many families use an encasement as the permanent base layer — fitted once and left in place — and then a washable fitted protector on top for day-to-day changes. The encasement stays put; the fitted layer is what you’re actually stripping and washing. This is the most practical combination for frequent or heavy wetting and is standard in many hospital and care settings.
It also means that if the fitted layer ever fails during a significant leak, the encasement catches what gets through — and the mattress itself stays dry.
Material and Comfort Considerations
Waterproof membranes vary. The cheapest use a thick PVC layer that feels stiff and sounds crinkly when the child moves — potentially disruptive for light sleepers or children with sensory sensitivities. Better options use thinner, softer PU laminates that are quieter and more breathable.
For children with autism or sensory processing differences, this matters considerably. A noisy or uncomfortable protector can be a genuine barrier to sleep. In these cases, look specifically for products labelled “quiet” or “breathable” — or test a fitted protector before investing in an encasement, since encasements are typically less forgiving on texture and sound.
If managing the sensory side of bedwetting products is a priority, the broader challenge is worth reading about in our guide to managing bedwetting stress as a family.
Care and Longevity
Most waterproof fitted protectors can be washed at 60°C, which is important for hygiene with frequent use. Check the label — some cheaper protectors delaminate after repeated washing or high-heat drying. A protector that lasts 6 months of nightly use is worse value than a more expensive one that lasts 3 years.
Encasements are generally less frequently washed (since they’re underneath another layer), but they still need cleaning periodically. Check that the zip is reinforced and that the seams are heat-welded rather than simply sewn — stitched seams are not truly waterproof and can allow moisture through under pressure.
What About Bed Pads and Mats?
Both protector types work well alongside a bed pad or absorbent mat placed over the fitted sheet. Pads absorb the immediate leak, reducing how much reaches the protector layer at all — and they can often be changed quickly in the night without stripping the whole bed.
This layered approach (encasement + fitted protector + absorbent pad + sheet) is the most effective setup for children who wet heavily every night, and it significantly reduces laundry load over time. It is used almost universally in paediatric care settings for this reason.
You can read more about how overnight product design affects leaks — and why mattress protection ends up being necessary in the first place — in our article on why overnight pull-ups leak.
Cost Summary
- Budget fitted protector: £8–£15 — adequate for light or infrequent wetting; check wash durability
- Mid-range fitted protector: £15–£30 — better membrane, quieter, more breathable; suitable for most ongoing bedwetting
- Quality encasement: £25–£60 — full mattress protection; sensible for expensive mattresses or heavy nightly wetting
- Both combined: £40–£80 total — the most thorough option for severe or persistent bedwetting
Fitted vs Encasement Mattress Protectors: The Bottom Line
For most families dealing with bedwetting, a good-quality fitted mattress protector is the right starting point — practical, easy to change, and sufficient when paired with an absorbent product. If your child is a heavy wetter, the mattress is valuable, or you’ve already had leaks damage a previous mattress, an encasement provides significantly better long-term protection and is worth the additional cost and effort.
The best all-round solution for nightly heavy wetting is to use both: an encasement underneath that stays in place, and a washable fitted layer on top that you change as needed.
If you’re still working out how to reduce the number of full bed changes you’re facing each week, the guide on how other parents manage night changes without burning out covers the layering strategies that make the biggest practical difference. And if you’re at the point where you want to understand whether anything can be done to reduce wetting frequency itself, knowing when to speak to a doctor is a useful next step.