so i was reading in the DIY section and there was something that was unclear. If you add the material onto the door, that it may absorb water and rust the door, which sounds correct. how do you put it on the door then? without it absorbing water?

 

most of the good stuff is a butyl rubber compond with a foil wrapper. Not sure how rubber or foil will absorb water.......

Unless you are doing it in the rain, it isn't a problem. I use a damp rag to wipe down the surface to clean it before I put mine on, it is often recomended in the installation instructions.