 Well, you definitely hit the nail on the head when you talk about partial sun because if you had more sun, you would have nature's mildew side there, nature's moss killer, which is sunshine. The more sunshine on a roof, more sunshine on a deck, the less you're going to have that sort of thing happening. There's a couple of products that you could work with that will solve this. One is called Spray and Forget. And the way that works is you literally spray it.