Listen to the guy who gave the detailed how to instruction, burning and removing etc. the other people are guessers and you will most certainly live to regret not tackling it properly. I made that mistake and it cost me dearly to put it right. dry rot is a fungal infection of the wood and travels via brick work plaster and wood all over your house if not treated, curing any damp is sensible but will not stop it once you have the infestation.