I have a Panabode flat log western cedar 'cottage' we are renovating. This summer we insulated the ceiling with approx. R-30 and roofed it with metal.
The logs are only 3" thick. We live in southern Ontario, Canada.  It is very cold right now. (-10F) this morning.  The walls on one side (south side) of our house are wet at the base the first 6" log is drenched.  Nothing is up against the walls. (learned not to do that the first winter) and the corner is wet about a foot or so up the wall.  We do not have an HRV installed yet.  How can the wall be so wet?  We have a dehumidifier going to try and dry it out.  WHAT is happening? 
Thanks,
Nicole

Sounds like the interior surface of the wall is simply lower in temperature than the dew point of the warm inside air, so when it touches the cold wall, you get condensation. Manufacturers of solid wood "log" homes claim "effective" R-values utilizing the mass effect, but 3" of solid wood is only about R-5. No amount of insulation in the roof and windows can stop that kind of condensation.

Exactly right, the actual indoor partial vapor pressure is reaching the dew point saturation vapor pressure. You can prove this for yourself and even estimate the moisture accumulation rate by running your numbers using our free DIY software:

Borst Building Assembly Moisture Analysis

So what is a possible solution to this problem? Seems to me that any attempt to add insulation to either side of the log wall would be a mediocre and expensive solution. So lessening the indoor humidity is a possible solution which would require either a whole house dehumidifier and/or a ERV as opposed to a HRV? Thanks.

attempt to add insulation to either side of the log wall would be a mediocre and expensive solution

It's the proper and green solution. What would have been better is to not build that "log" home in the first place, particularly not in that location.

A 3" thick log with chinking has an R value between R2-4, which isn't very much at all. At -10F outdoors, 70F indoors, an R3 wall is losing about 27BTU per square foot, which puts the inside surface temp of that wall something like 50F, less nearest the chinking. If the 70F indoors is running 35% RH, the chinking will all be well below the dew point of the room air, and will saturate, dribbling onto the logs. Gravity and air-temperature stratification will make the lowest log the coldest and wettest.

To get close to the performance of a code-min 2x6 wall or better without endangering the logs, put a crinkle type housewrap on the interior (conditioned space) side, and 3" of unfaced rigid Type-II EPS applied as two layers of 1.5", seams taped with housewrap tape, and staggered by a foot or so. Tack the foam in place with foam-board adhesive to aid in assembly, and affix them permanently in held in place with 1x furring though-screwed to the logs 24" o.c.. Then mount the gypsum to the furring with 1.25" wallboard screws. Use an always-flexible "windows & doors" can-foam to seal the top and bottom edges of the foam to the housewrap.

Do NOT install poly sheeting anywhere in that stackup, since you want the logs to be able to dry toward the interior as well as the exterior over the summer. At 3" thickness the logs run about 0.3-0.4 perms of vapor permeance, but even a tiny amount of air leakage at the log layer will let it dry at least a little bit to the exterior even during the winter. With 3" of Type-II EPS the foam layer runs about 1 perm, which will slow the moisture transfer from the interior to the logs to an acceptable rate for a southern Ontario climate as long as it's air-tight. If the inspectors insist on seeing sheet goods (or if you want some insurance) a "smart" vapor retarder such as Intello Plus or Certainteed MemBrain between the layers of foam will reduce the mid winter vapor permeance of the foam + vapor retarder to about 0.5 perms, but rise to about 1 perm, cutting the drying time in half, should the interior side of the logs become saturated.

It's absolutely critical to make these layers as air-tight as possible- any air leakage that gets through the foam will accumulate in the logs at rates many times that of vapor diffusion alone. An alternate approach that might be safer would be to shoot 2" of closed cell spray polyurethane directly on the interior side of the logs. Use chunks of 2" XPS as spacers for pre-mounting the furring for the gypsum prior to the spray foam, and the foam installers can then use the furring as their depth guide.

With either the 2" of 2lb foam OR 3" of EPS with 3" of log exterior you'll be at a "whole-wall" R of about R14-R16, which is comparable to a clapboard sided plywood sheathed 2x6 16"o.c. framed wall with R23 Roxul in the cavities, at about the same thickness as the 2x6 wall.

But for either approach you'll have to wait until June to give logs sufficient drying time after the winter adsorption period, lest you end up trapping some of that moisture in place, which could then take the better part of a year or more to come down to an acceptable moisture content if you sealed it up after the winter soaking it's getting.

Panabode would have tongue and groove matching at top and bottom. No chinking. No gasket.

Even if the cottage is many years old, the logs continue to move so the allowances for settling need to remain intact.

Wow. Thanks Dana1.

It's been a crazy winter with those polar vortexes taking us down to -27 on several occasions. The -10 looks positively balmy now. We actually got ice in the corners and on the wall.
BTW, the Panabode was built in 1965 as a cottage on 23 acres of protected land. Green was a colour, not a building option. We are slowly turning it into a home as time (we both work full time) and money permit. The price of land in Southern Ontario is crazy.
I am not particularly attached to the look of the flat logs outside is there an option for insulating it from the other side? I've looked into spray foam. It's very expensive. Have you seen what the Scandanavians do with the outside insulation on their log homes?
Thank you all again.
n

Wow, thanks too to Dana 1.
We are looking to put 4" Roxul Comfort board & Hardie plank siding on exterior of 1960's panabode house. Would you still recommend using "MemBrain" type AB? We're thinking to put AB outboard of insul (to limit wind washing of insulation). Not planning on VB. We were intending to do the work this fall/winter. Comments? I see the recommendation not to trap the fall / winter moisture. Could this timing still be ok if drying could happen towards inside of building and Roxul will allow moisture out? Building is also in southern Ontario.
On another note, there also seems to be a persistent "smell" inside... I wonder if it's because of moisture issues nicoledev mentioned. Other experiences?
Thanks everyone... I hope this gets through so many years later!

it's most likely condensation