Assembling Log Shell on Site
Before the logs even arrived we had put in a lot of work at the cabin site. We had the foundation and basement put in, field stones mortared in along the block, and the first floor platform finished.
It was quite a challenge to get the log trucks and trailers into the lot. You need a good driveway and a lot of clearance. They also used a crane to lift and maneuver the logs into place. This presented quite a challenge since our lot was dense with trees.
The sill logs are the bottom logs in each wall. They're cut flat on the bottom and are set over a layer of sill sealer material to prevent air leakage between the log and the platform.
Once all the sill logs are in place, they measure corner to corner to make sure the layout is square. Squaring them up puts them in the same position as when they were initially assembled which is necessary for setting the rest of the logs properly.
Once in the correct position, they drive 12-inch spikes into the sill logs to secure them.
As the full logs go in, the corners are fit together. Corner notching is the key to building a log home. It binds the logs together and helps determine the overall look of the cabin.
Our notches are called "saddle notches." As the logs dry, they'll shrink together slightly forming an even tighter seam.
The joints don't need any nails, but they do lay a piece of R-11 insulation at each joint as a weather barrier.
First Floor Walls
If the notches on the joints all line up the same as the original assembly, the walls should be plumb and square.
These logs are red pine. Their butts are wider than the tips, so they alternate them as they move up. And to enhance the handcrafted look the log ends run past the notches at random lengths. For a less rustic look, you can cut them to a uniform length.
The gaps between the logs will be filled later with a weather-proof chinking material. Logs can be cut to fit snug without chink in the Scandinavian scribe style, but that would take longer and cost more.
The openings for the windows and doors will be cut later. But now they reinforce those openings with rebar. These get hammered into the holes that were drilled at the log yard. These will hold the log ends in line once the openings are cut.
Tie logs are used to tie opposing walls together. Ours carries from the front entryway to the back porch so it's actually the longest log in our home.
Logs are also used for joists under our second floor. They're saddle-notched and cut flat on top for the flooring.
The log joists are hefty so the spacing is wider than in dimensional framing, and it can vary from log to log. You just want to be sure a log falls directly over an interior wall so you have something to secure it to.
Posts and Purlins
Once the joists are all down, the cap logs can be set in place over them. These are notched to fit over the joists and hold them in place.
Next the crew cut and fit a log post to support the ends of the logs over the back porch. These posts needed footings below them for support. They also put two huge log posts at the entryway.
With the vertical supports in place, they set in the purlins. Purlins are unique to log home building. They typically span from gable end to gable end horizontally providing support for the roof and the dormers. Their ends are tied into the gable end logs.
The gable end logs are typically "spiked" together for vertical strength. This also makes it possible to swing 2 or 3 into position at once.
When the gable ends are the same height as the master bedroom outside wall, the ridge log for the master bedroom roof is set in place.
Over the house, the purlins provide the main support for the roof. Over the master bedroom, they use log rafters for the roof.
The rafters are planed flat on the top to create an even surface for securing the roofing material. Short logs are wedged between them to fill the open spaces where they cross the wall logs.
The addition of gable dormers and shed dormers make the roof framing quite complicated. Gable dormers have peaked roofs framed by a log ridge and purlins. Shed dormers have flat roofs that rest on the angled logs of the front and sidewalls.
The very last log of our shell was the ridge log which finished off the very peak of the roof.