Hans "Hi", To be honest with you, I've never heard of "White Rot" So can you tell me what it looks like, and tell me if there is little vine like roots on the surface of the wood. Can you tell me if the wood is soft and wet, or soft and dry is the surface of the wood cracking into small cube like shapes ? Have you had problems/repairs with the roof in the past, has water ever come in. Please come back to me on this I feel its important and from what you have read in the fungus file, you can see I know what I'm talking about.... John 2000. PS: please try Tempor, by all means, it may help.?