Insulating a Log Cabin
I am getting ready to insulate and rebuild some interior walls of a cabin in Slovenia. The cabin is 3-sided Spruce logs with an average width of 7.5 cm (3 inches) at center of the log. Old construction with lots of gaps between logs (will be sealed with chinking at a later stage). My initial thoughts on how to go about this were:
1. Permeable vapor seal tacked to logs
2. EPS foam (5 cm)
3. AAC blocks for interior walls (non-load bearing/ 5 cm)
I calculated this should give me an R-value of approximately 15.5 with good thermal mass. But, I am not sure if I need the vapor barrier (house wrap) on the inside of the logs before EPS styrofoam or if this would cause problems with moisture.
Thoughts or suggestions?
Thanks in advance.
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There are a few discussion threads on insulating log homes, such as https://www.greenbuildingadvisor.com/article/fixing-a-leaky-log-home.
If it were my home, I would install an air barrier (taped house wrap) on the exterior and cover it with taped rigid foam. I'd cover the foam with stucco or siding. If using siding I would also install furring strips to create an air gap (to promote drying).
I'd probably avoid the AAC since it offers modest R-value compared to rigid foam.
Just for clarification (in case I am reading your reply wrong, apologies), the outside is log, so all the layers I am putting in is in the interior.
You will lose quite a bit of interior space. Unless the home is stripped out, you may encounter some challenges with relocating utilities, trim, and doors.
Here's quote from the article I referenced earlier:
“If you decide to go ahead and install interior rigid foam, pay close attention to air sealing,” (GBA editor Martin) Holladay says “Multiple layers of rigid foam will be better than a single layer; make sure that the second layer of rigid foam has staggered seams, and seal the seams of every layer of foam with high-quality tape.”
Excellent. Thank you.