[DD716TED]

About 6 years ago I made / installed a sliding (barn type) door to isolate the patio / garage hallway in bad weather.. I fabricated it from groved wood (not GP) siding and 2 / 4's.. I assembeled it with glue and screws.. then primed the entire door, caulked all open seams/ screw holes and painted it to match the house... Now. 6 years later I have to replace the door due to wood rot and soft paneling on the bottom 4 inches of the door as depicted by the red rectangle on the attached photo.. This deterioration is I am sure due to the door getting wet during lawn sprinkling and wet weather we have here in Washington State.. Now I am going to build a replacement door using the same materials.. My question is to avoid future rot in the same location, is it practical to coat the entire 1/3 of the door with fiberglass resin (without cloth) or something else to stop water penetration prior to painting? The top 3/4 of the door are fine with no problems.. Any ideas / thoughts would be appreciated...