Building out costs more than up-and-down. The most popular log-home arrangement is the story-and-a-half, which features open space over the great room and a partitioned or open loft area. It’s practical for homes between 2,500 and 4,000 square feet, and adds efficiency to smaller homes, especially ones over a basement.
A finished basement is cheaper than a second story, maybe even than a loft that has plumbing and partitioning, especially one with fancy railings and staircase. Basements offer little temptation or occasion to use logs. Cut costs on full or partial upper levels by using conventional materials, not logs. Thin log siding continues the log look, but board-and-batten or shingles better complement main-level logs.
Building out may use more logs and definitely needs more foundation and roof. A two-level house over a finished basement can reduce these costs and its footprint by a third, increasing heating and cooling efficiency. Building out has its advantages. Live all on one level rather than go up and down stairs. A lower profile might flatter your site better. Plus, a small house rarely needs more than one level. Just add a porch.
Large single-level homes often distance space and contain sound, an advantage over super-tall great rooms with upper-level rooms that amplify the ceiling’s echo. If you like cathedral ceilings, one-level homes can have one in every room.
If you build on one level, make it interesting. Add bumpouts or angle two wings off the great room. Consider roof dormers, not for headroom but to break up the roof mass. Yes, these enhancements cost extra.
If no one-level floor plans interest you, check two-story ones. Larger homes may have enough rooms on the main level to accommodate your needs (at least three bedrooms and two and a half baths. You’ll even gain space, maybe a room’s worth, by not needing the stairs.