Ive got a 10' x 8' Shiplap shed, with which I coated it with a few coats of Wickes Timbercare a few years ago and have found that there was traces of water on the inside walls over the winter. I think I need to use something better than Wickes own brand timber care. Cuprinol Ducksback is meant to be quite good but i know that its designed for rough sawn timber. Any ideas on what i could use please as my shed is planed softwood??