Wow, thanks! much appreciated, i only thought there was the single house wrap tyvek so i didnt look into it! If i used say, goretex (3 layer) or pertex (shield+ or endurance or something) instead of tyvek, would that be more suited or would tyvek still be the best? I mean i dont think ill get any lighter than tyvek, but on grounds of waterproofing and breathability.