Georgia-Pacific's Prime Trim and Temple-Inland's Trim Craft are both pre-primed, 5/4-inch wood-fiber trimboards. The wood-fiber material is similar to hardboard, but don't let that bias your expectations. I soaked a sample of each product in water for a week. While I expected the boards might turn to mush, the Georgia- Pacific product hardly swelled, and the face was barely soft enough to scratch with my fingernail. The Temple- Inland product was a little softer and the edges started to chip after pulling it from the bath. But the test suggests both materials would hold up as fascia and skirt trim, even when the gutters overflow, or where splashback is a problem. The boards are pre-primed on all sides, and