The epidermis (skin) is typically ten to thirty cells thick; its main function being to provide a waterproof layer.
For example a non-breathable waterproof layer will make ineffective the performance of good base and mid-layers.
Land plants maintain adequate tissue hydration by means of an outer waterproof layer.
Keeping dry is critical, so a strong, waterproof outer layer is essential.
Wear waterproof outer layers to keep you dry.
Butter and margarine act as a waterproof layer for bread against wet foods like sliced tomato.
The epidermis is typically 10 to 30 cells thick; its main function is to provide a waterproof layer.
A strong, waterproof outer layer (and a space blanket for emergencies) is essential.
Whether you're in cycling kit or ordinary clothes, if you must have a waterproof layer just get a simple gore-tex shell.
The bark is also used to create a durable waterproof layer in the construction of sod-roofed houses.