One of the worst things you can do for your wood porch railings, beams, posts, eaves and facia is to let vines grow on them. Pictured here is a huge ivy vine growing all over a house. The vines eventually rot out wood members and encourages mildew growth. This will cause costly repairs involving wood replacement, mildew cleaning and repainting. Some people feel that vines growing on a house is charming and attractive, and it may be, but it isn’t practical or wise.