It should not be a great deal of work if the job has been done right from the start. Some construction contractors and so called carpenters throughout the years in this industry has installed the wooden products to the best of there ability ,but left out the most important part of the job regarding protection or treatment of the particular product say for instance a door that was installed. It is to protect the top and bottom of the door panel.
These areas are always over looked and will never get the nourishment that wood require as we always say that your wood is or should be still alive.
Have you ever seen a door where the outside is still intact but the core is completely rotten? this is the very reason the door or window or and wooden product will rot is the fact that it is never treated on the top and bottom or sides for that matter.In order to prevent this from happening is to remove the “door” and seal it from the bottom and the top and make sure that the grain of the wood has obsorbed enough of the treatment product used to seal it of from any moisture that can possibly penetrate and cause damage.