Spruce vs hemlock clapboards – GreenBuildingAdvisor

In Vermont, you’re probably talking about spruce clapboard from the Ward mill? They make high-quality, vertical-grain spruce clapboards in a few grades. Vertical grain makes them very stable. Spruce is not naturally rot-resistant so you should use a rainscreen and finish at least the faces, and preferably all sides, if you want them to last. Their biggest drawback is that they only come in short lengths, up to 6′. Most carpenters are used to installing longer boards.

For hemlock, I have only used western hemlock, which is related to eastern hemlock but they can be found in long, clear lengths, with vertical grain if you want it. Hemlock is more rot-resistant than spruce but it should still be finished with something and be installed over a rain screen.