Dangerous UV rays not just bring about discoloration while in the stain but can also very seriously harm the deck boards. Solar rays can cause the boards of a deck to separate, warp and crack. Would be the deck painted or could be the earlier stain a solid stain? Either http://israelohwkh.look4blog.com/37507940/the-only-guide-to-residentialpainting-contractors-deck-painting-service-concord