Ply shed cladding immediately suffering

[JohnD]

I'd use that on a door in a protective porch, but for a shed, compare that to the price of fence stain, which leaves a water-repellent waxy coating

http://www.screwfix.com/p/ronseal-brushable-one-coat-fence-life-dark-oak-9ltr/45657

Provides long lasting, fade-resistant protection to sheds and fences. Excellent coverage. Dries in just 1-2 hours. Safe for use around pets and plants. Covers approx. 6m²/Ltr.