Most rotting happens at the non-primed ends of boards, thanks to carpenters who hate painting. (Just ask any carpenter.)  So, you will notice that my repairs always include primed ends so rot can’t attack that way.  I also use plastic whenever possible.  These boards below will be primed before they are set into place in this deck repair job.

To see the detail of this work, right-click on the picture and select “Open in New Window”