How did pioneers add a room onto a cabin?

[Sampiro]

I'm from the south. Down here when people added onto a one room cabin it was usually to build an open hallway (a dogtrot) and then a duplicate pen and cover the two in one roof. The next two rooms would be made by enclosing ends of a full length porch into what's called 'shed rooms'. In the dogtrot on the farm where I grew up, the original room was built low to the ground and when the addition was made it was a full platform, at which time the original was stripped a bit, the pen rolled on logs [pushed by humans and pulled by mules] the raised with rented house jacks and pulled into place. Rarely did they add a log room directly onto a log room.

In the Midwest and the north I've seen a lot of cabins where the log addition was smack against the original structure. What I'm wondering is how this was done. Assuming the original structure was dovetailed squared logs, does this mean that the old logs were lifted and notched and the new logs inserted into them, or did they just build a new room and use a lot of patching and mud and clay in the place where the two structures joined, or... what exactly? Also, in chopping through the logs to make a door between the old structure and new, would there have been any structural damage?

*In the south the main time I've seen this is what's called the "saddle bag" style. Essentially two log cabins are joined to each other and each has their own door to the outside, and frequently there was no door between the two- you just had to go out and come back in to the other room. This was especially freqent in slave quarters on plantations where different families lived in each unit.

[elfkin477]

This website indicates that when they built an addition flush against the existing house, it was common to cut down an existing window to make it into a door to the addition.