Log posts supporting a deck blend with the look of a log house and make the deck seem as if it belongs to the house rather than being an afterthought. Plan the installation of log posts so they'll be sturdy and long lasting, as well as aesthetically appealing. Choose a durable species like cedar or black locust or use treated logs and let them season for a few months so they've finished shrinking and drying. Remove the bark with a hatchet or drawknife to discourage insects and dampness under the bark.
Dig a hole in the location of each post, using a shovel or power post-hole auger. Make the hole deep enough to extend below your local frost line and to reach compacted, undisturbed soil at the bottom. Dig the hole at least 2 inches wider than the diameter of your post.
Fill the holes with wet concrete up to the level of the soil to create concrete footers for the posts. Purchase bagged concrete and mix it yourself with a shovel in a wheelbarrow, if you only have a few shallow holes. For more or deeper holes, rent a mixer or order concrete delivered and poured by a concrete company.
Insert a 6-inch anchor bolt in the center of each footer while the concrete is still wet. Leave 3 inches of the bolt extending vertically above the surface of the concrete. Shape the top of the concrete in a slight crown so the center is highest, using a trowel, so water won't pool under the post when it's installed. Let the concrete dry.
Choose logs that are at least 6 inches in diameter and cut them to the length necessary to support your deck. Notch the sides or cut the tops level to support the deck joists, depending on how you're constructing the deck, using a circular saw or chainsaw.
Drill a hole in the center of each post bottom to fit over the anchor bolts. Set the posts down over the bolts and prop them in place if necessary with a board temporarily nailed to them, until you install the rest of the deck.