Hey everyone. I own a 1970s Panabode cottage in Ontario. The structure is comprised of 2.75” thick T&G milled logs. The last two years I’ve lived at the cottage during winter (down to -30c) and noticed quite a few issues.
Substantial heating bills with the propane furnace running 8+ hours a day in January. Warm air venting to the outside through tiny gaps in the log joints and top wall log/eave transition and causing exterior frost build up.
I spoke with some log builders in the region and they advised on doing an exterior energy retrofit and I wanted to get everyone’s opinion on the plan:
The house is on piers. Crawl space is conditioned and insulated with exterior wall spray foam insulation. The roof is vaulted and the decking is 2” thick cedar T&G. The roof boards extend past the eaves (so there is no soffit). There is 6-8” thick batt insulation on top of the roof boards. Not sure if there is a vapor barrier on top of the roof boards (maybe tar paper?).
Seal every log joint with log caulking. Larger gaps will have backer rod installed. Especially the wall/eave gaps and log tail joint details. Was also thinking of adding butyl flashing tape on the wall edges to protect against seasonal log movement: corners (lapping log tails), Top where the wall meets the eave. Interior corner joints as well.
Remove windows one by one (currently installed in the 2.75” thick log profile) and buck out 2x8 window frames with proper flashing. The window frames would allow for log movement by using a slide (angle iron embedded in log ends on the sides of the window opening, and the 2x8 frame secured to the metal)
Install 4” T&G XPS panels (R-20) directly against exterior log face. Seal all gaps with tape, add flashing tape where required. Bottom of the walls will need custom metal Z flashing
At the top of the exterior walls, the XPS will butt directly against the cedar roof boards at the eave.
Install tyvek water barrier. Tape seams.
Install rainscreen: 1x4 vertical strapping 16” OC using 6” timberlok screws. Cedar shiplap installed on the strapping.
Does this sound like a reasonable plan overall? Any advice would be appreciated!