Do You Need a Mattress Protector With a Waterproof Fitted Sheet?
If you’ve discovered waterproof fitted sheets, you might be wondering:
Do I still need to put a mattress protector underneath?
It’s a fair question. We’re so used to making kids’ beds with a mattress protector first and a fitted sheet over the top that it can feel strange to skip a layer.
But if your fitted sheet already has waterproof protection built in, you may not need a separate waterproof mattress protector as well.
And that’s kind of the point.
Here’s how it works.
What does a mattress protector actually do?
A traditional mattress protector sits directly over your mattress and underneath your fitted sheet.
Its main job is to create a barrier between the mattress and all the things that come with having kids:
Leaking nappies. Toilet-training accidents. Spilled drinks. Sickness. And those completely unexplained wet patches that nobody seems to know anything about.
You then put a regular fitted sheet over the protector to create a comfortable sleeping surface.
So you end up with:
Mattress → waterproof mattress protector → fitted sheet
It works.
But it also means two separate layers to buy, fit, remove and wash.
How is a waterproof fitted sheet different?
A waterproof fitted sheet essentially combines those two jobs.
It looks and feels like a fitted sheet, but has a waterproof barrier built into it to help stop liquid reaching the mattress underneath.
Your bed setup becomes:
Mattress → waterproof fitted sheet
That's the idea behind NUMI.
We wanted to create a fitted sheet that looked beautiful enough to be the actual bedding, while quietly doing the job of the mattress protector underneath.
Two products became one.
So, do you need both?
If your fitted sheet already provides the waterproof protection you're looking for, you generally don't need to add another waterproof layer simply to perform the same job.
Of course, every family is different.
Some parents may still choose to use additional mattress protection for their own reasons, particularly if they want extra backup during periods of frequent accidents.
But the reason we created NUMI was to make a separate protector unnecessary for everyday mattress protection.
One sheet.
One layer.
One less thing to think about.
Why does one less layer matter?
At 11am? Maybe it doesn't.
At 3am with a wet bed and a very sleepy child?
It matters.
With a traditional setup, you're potentially removing the wet fitted sheet and then the mattress protector underneath before replacing both.
With a waterproof fitted sheet, you're dealing with one layer.
Pull the wet sheet off.
Put the clean one on.
Get everyone back into bed.
It's a small difference that feels considerably bigger in the middle of the night.
What about comfort?
This is probably one of the biggest concerns people have about waterproof bedding.
If the waterproofing is built into the sheet, does that mean your child is sleeping directly on something plasticky?
It shouldn't.
A good waterproof fitted sheet should still feel like a proper fitted sheet.
NUMI sheets have a 300 thread count GOTS-certified organic cotton sleeping surface combined with a breathable waterproof TPU layer.
So your child is sleeping on soft cotton rather than directly on the waterproof membrane.
We specifically wanted to avoid the stiff, noisy, crinkly feeling traditionally associated with waterproof mattress protection.
What is TPU waterproofing?
TPU stands for thermoplastic polyurethane.
It's a flexible waterproof material commonly used to create a barrier against liquid.
For bedding, TPU can be bonded with fabric to create waterproof protection without relying on the thick plastic feel you might associate with older-style mattress protectors.
For us, it meant we could create a sheet that still felt like beautiful cotton bedding while adding the practical waterproof function underneath.
Are waterproof fitted sheets good for toilet training?
This is where they really come into their own.
Nighttime toilet training often means accidents.
And accidents mean washing.
Anything that makes that process simpler is a win in our books.
Rather than layering a fitted sheet over a separate waterproof mattress protector, you can have one waterproof fitted sheet on the bed and another clean one ready to go.
We call it the two-sheet setup:
One on the bed. One waiting for 3am.
If there's an accident, remove the wet sheet, replace it with the clean one and deal with the washing in the morning.
Simple.
What about babies and cot mattresses?
Waterproof bedding isn't only useful once toilet training begins.
Babies have their own impressive collection of ways to make a mattress wet.
Leaking nappies, milk, dribble and sickness can all find their way onto cot bedding.
A waterproof cot sheet gives you the comfort of a fitted cotton sheet while helping protect the mattress underneath.
Just make sure you're choosing the correct size for your cot mattress and that your fitted sheet fits securely. Always follow current safe-sleep recommendations when setting up your baby's sleep space.
What should you look for in a waterproof fitted sheet?
If you're considering replacing your traditional sheet-and-protector setup, don't look at waterproofing alone.
Consider the whole product.
The sleeping surface should feel comfortable against your child's skin. The waterproof layer should be flexible. The sheet should fit the mattress securely. And perhaps most importantly for children's bedding, it should be easy to wash.
After all, the whole point is to make life easier, not add another complicated item to the laundry pile.
One sheet doing two jobs
NUMI started with a pretty simple question:
Why are we buying a mattress protector AND a fitted sheet when one product could do both?
So we made one.
Soft organic cotton on top.
Waterproof protection underneath.
Hand-painted prints that actually look beautiful in your child's room.
And one less layer to wrestle with when an accident happens.
Because children's bedding needs to be practical.
We just don't think it needs to look practical.
Waterproof. And cute.
