Externally insulating a rectangular log cabin in the French alps

This isn't news so much as a homeowner's question posted to a building forum. A homeowner with a log cabin in the French Alps, at 1,200 meters elevation near a snow-making machine, asked for advice on adding exterior insulation to the outside of the log walls. He's trying to decide between a few approaches: mounting brackets that let a new stud layer slide slightly against the logs (since log walls shrink and swell with moisture), then insulating with rockwool facade insulation directly against the existing logs; adding a sealed air and moisture barrier between the old logs and new insulation, which he worried would be hard to make airtight with all the sliding hardware; or leaving a ventilated gap behind the insulation so the wall can "breathe," at some cost to insulating performance.

One responder suggested a different method: coating the logs with a liquid-applied air and moisture barrier, then building a "Larsen truss" on the outside — a framework of plywood gussets and outer studs — filled with blown-in insulation, which avoids the sliding-bracket complications entirely.

For homeowners here, this is really a case study in a problem that comes up whenever you add exterior insulation to an older wall that moves or needs to dry: balancing airtightness, moisture control, and insulation value. If you're considering exterior insulation on a log, timber, or older wood-frame home, the same tradeoffs — vapor barriers, ventilation gaps, and wall movement — are worth discussing with whoever designs your retrofit.