Why the PUL in your cloth diapers cracks and how to avoid it
Coralie Mabouledecouche
Some families notice that their cloth diapers are becoming less leak-proof: the PUL fabric cracks, splits, or loses its elasticity. This phenomenon, often wrongly attributed to improper use, frequently stems from an invisible factor: the composition of the water and the overall care routine.
To learn more, check out our articles: Washing routine , Machine cleaning , White vinegar , Compatible detergents , Mistakes to avoid , Nighttime leaks .
Summary
Why PUL fabric can crack or split
PUL is a technical membrane that provides waterproofing while allowing the fabric to breathe. Certain conditions accelerate its degradation:
- Excessive temperatures or prolonged drying in the sun;
- Use of unsuitable products (vinegar, essential oils, acidic stain removers);
- Highly mineralized water (limestone, manganese);
- Washing cycles that are too short or insufficient rinsing.
These factors gradually weaken the membrane, causing rigidity and then cracking.
The impact of water composition on washable diapers
Water strongly influences the lifespan of PUL . Hard water, rich in calcium or magnesium, deposits a mineral film on the membrane and absorbent fibers, reducing flexibility and performance.
- weakened PUL;
- Rough and less absorbent inserts;
- Overall absorption decreased.
Even a perfect washing routine cannot compensate for overly aggressive water.
How to protect your cloth diapers
Adopt these essential steps to preserve PUL:
- Install a limescale (or manganese) filter at the water inlet;
- Use a filter on the machine's hose if main installation is not possible;
- Choose an enzymatic powder laundry detergent that is suitable for the hardness of your water;
- Avoid white vinegar, essential oils, pure soap, bleach and acidic stain removers.
Maintaining your machine to preserve the PUL
A clean machine protects your diapers. Run an empty cycle at 90°C every month with a specific care product to remove mineral deposits and maintain the quality of the PUL.
FAQ – PUL and care of washable diapers
Why is the PUL on my washable nappies cracking?
PUL often cracks due to excessively hard water, extreme temperatures, or acidic products. These factors attack the waterproof membrane.
Can a cracked PUL be repaired?
No. Once the membrane is damaged, the waterproofing is permanently lost and the layer must be replaced.
How to avoid rough diapers?
Choose a detergent adapted to the water hardness, rinse for long periods and install a limescale filter to preserve the softness of fabrics.
Which products are not recommended for maintenance?
Avoid white vinegar, essential oils, Marseille soap, bleach and acidic products: they degrade PUL.
🌿 MBDC Tip – How to diagnose a damaged PUL
Do you suspect a damaged PUL ? Three checks can confirm this:
- Water test: if water quickly passes through the inside of the panties, the PUL is no longer waterproof.
- Visual inspection: gently stretch the fabric in the light: white lines = cracked membrane.
- Feeling the fabric: a stiff or dried-out PUL reveals a degraded membrane.
💡 Tip: Keep these diapers for trials or short naps, and replace the ones that are too worn.
Conclusion
Cracked PUL fabric isn't always due to misuse: water, detergent, or a poorly maintained washing machine can all be the cause. With proper care and a suitable routine, you can extend the life of your reusable diapers and maintain their leak-proof properties.
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