I live in Seattle and I put a fir porch on my house, covered, with southern exposer, gets some rain and lots of sun.  I put on a deck and porch preservative on the advice of Dalys ( a Seattle paint store) less than a year ago.  There’s been a lot of expansion and contraction, it’s now drying out and some slight cracking.  Anyone have any suggestions on what to use on it ( besides paint!)