I have a 3 yr. old house whose yellow pine trimwood won't hold paint. The first round of primer/paint peeled off in a lot of places after only 6 months. Now, nearly 2-1/2 yrs. later, we are attempting to redo it (sanding, proper primer/paint combination), but after only a few days the sap is streaking yellow and the paint is being shed again. Any ideas/suggestions out there?