Hi. I am planning to install a 5" round stainless steel liner in my chimney for my wood stove. I don't want to use a rain cap if I don't have to because of the way it would look on my house. Are rain caps necessary with a metal liner? The clay liner has been open to the rain for decades and we haven't had any problem with water. I'm not sure how using a round metal liner will change that. Thanks for your help!