The door and wooden threshold for my walk-out cellar are exposed to the elements. I've noticed that the threshold has taken a beating and appears ready to crack on a seem. I was thinking of covering the threshold with some sort of protective covering that would keep the rain/snow off. Is there some sort of product that would accomplish this? I don't want to replace the threshold, as, other than for the potential for splitting, it's in good shape. One of my friends suggested that I simply apply an adhesive roof covering that is used on flat roofs. (I think that it comes in rolls). Any suggestions?
I don't think that there's too many products out there that will be durable enough for use on a door threshold. Adhesive products won't keep water from getting into the threshold in this application anyhow.
A good sanding, a coat of primer, and a couple coats of high-durability oil-based paint might buy you some time.
I'd just save the effort and replace the threshold with a new one.