01 Three layers, three different jobs
Waterproof socks and similar items often use a thin functional membrane between an outer fabric and a lining. The fabric next to your skin and the membrane that blocks rain and wind each have a different job.
- 01 Outer
- 02 Membrane
- 03 Lining
- 01Outer fabric
- Protects the membrane from abrasion. This fabric itself may absorb water and become wet.
- 02Membrane
- Helps block liquid water and restrict wind while allowing water vapour to pass through.
- 03Lining
- Provides comfort against the skin. Moisture absorption and warmth depend on the fibres and fabric thickness.
02 Waterproof, windproof and breathable
Keep external water from reaching the inside
A hydrophilic non-porous membrane blocks liquid water with a continuous solid structure. A microporous membrane resists water entering its tiny hydrophobic pores. Both have limits to the water pressure they can withstand; seams and product construction also affect waterproof performance.
Reduce wind penetration and heat loss
Wind passing through gaps in fabric carries away warm air close to the skin. A membrane restricts that airflow. It does not generate heat: warmth also depends on the lining and fabric thickness.
Transfer internal moisture as water vapour
A hydrophilic non-porous membrane absorbs water molecules from vapour, transfers them through its structure and releases them outside. In a microporous membrane, vapour moves through tiny pores. This is different from bulk airflow, which is why a membrane can resist wind and still be breathable.
LEAKDRY describes its waterproof-breathable material as a hydrophilic membrane in its official FAQ. Membranes do not all use the same mechanism or offer the same performance. Moisture transfer also depends on temperature and humidity inside and outside the product. Read the manufacturer’s explanation
03 What to know before you use it
Does a wet outer fabric mean it is leaking?
Not necessarily. The outer fabric can absorb water while the membrane still keeps it from reaching the lining. Surface water repellency and membrane waterproofing do different jobs. If the inside feels wet, also consider sweat, water entering over the cuff and possible membrane damage.
Does breathable mean I will never feel sweaty?
No. Moisture can build up when you sweat faster than it can escape. Hot, humid conditions and the shoes or clothing worn over the item also matter. Moisture absorption and wicking depend partly on the lining fibres and fabric structure.
Can water reach above the cuff of waterproof socks?
Water can enter from the top if it rises above the cuff. A waterproof membrane does not seal that opening. Watch for splashes and rain running down into the sock as well as the depth of the water.
Are all waterproof items equally warm?
Wind protection alone does not determine warmth. Check each product’s lining material and thickness for the season and conditions. How much you sweat and how the socks fit inside your shoes also matter.
How can I help them last longer?
Avoid sharp stones, thorns and other objects that could puncture the thin membrane. Wear waterproof socks with suitable footwear, and follow each item’s care label for washing and drying. One care routine may not suit every material or construction.
04 Porelle®: a membrane brand
Porelle® is a waterproof-breathable membrane brand from PIL Membranes Ltd in the United Kingdom. It is a functional membrane used with outer fabrics and linings, rather than the name of a finished fabric or sock.
Its official technology range includes microporous PU, hydrophilic PU and PTFE/PU bicomponent membranes. Different membranes serve different uses, so a brand name alone does not establish a waterproof or breathability rating.
This introduction to Porelle® is general material information. It does not mean that all products sold by our shop use Porelle®. Refer to the specifications shown for each product.
Explore Porelle’s official technologiesSources
- Porelle — Our Technologies — Membrane types and moisture transfer
- Porelle — Performance — Sports and leisure applications
- LEAKDRY — FAQs — Hydrophilic membranes and use precautions
Checked on 26 October 2026. Edited by Juo Trading as a shopping guide. The diagram illustrates a general construction, not the cross-section or test results of a particular product.
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