Chinking - Mortar "Breathes" = Mortar Drafty?

[Klapton]

I was reading the book, Living Homes by Thomas J. Elpel, and was a little troubled by something I read. I've read in some of the articles here that the fact that old-fashioned mortar chinking "breathes" is a good thing, because moisture will not get trapped between the logs, causing rot. This, combined with the simplicity and inexpensiveness of mortar makes it sound very attractive. But then I read this:


This [mortar] chinking method is both inexpensive and easy, but unfortunately there are some problems with it. Both the fiberglass and the morar are porous, so the wind blows right through them. ... the wind went right through the mortar joints...

Did the author just do a crappy job, and didn't get it sealed well? Or is mortar chinking indeed DRAFTY rather than just "breathing" (i.e. able to slowly release moisture-laiden air over time)? Can someone who has spent some windy winter storms in a mortar-chinked home clarify?

The author went on to say that going over the chinking with a modern, latex-based product cured his problem. But I guess I'd just like to know ahead of time whether "breathing" really means "drafty" or if there is some other explanation of this author's description.

[kahle]

I have spent many a night in a mortar chinked log home. And, no, mortar chinking does not mean it is drafty.

Think about it. Are brick houses automatically drafty? There are more mortared seams in a brick house than in any log house. Wind doesn't blow through solid mortar. The seams between logs do demand a little more care. If you chink green logs before they have fully cured, they will shrink and leave a gap that the wind can blow through. If you are careful to put your chinking nails into the bottom log only, then the gap will always appear on the top of the mortared seam and you can easily fill it with thin mortar from a pastry bag once the curing process stops.

You can also put materials inside the chinked seam to act as a moister barrier between inside and outside. I used a single bead of closed cell foam insulation at the very center of the seam. This keeps the wind from blowing through even before the mortar is inserted.

[JeffandSara]

Hello, Klapton--

I wondered about this when my husband took the LHBA class with Skip years ago, so when I attended the class at Skip's ranch a few months later, it was on my mind. I attended on a cold, windy, rainy weekend in March, and while touring Skip's home I found a gap in the chinking wide enough to stick my little finger into. With a storm blowing outside, I couldn't feel the TINIEST draft with my pinkie actually IN a gap in the chinking. I was impressed! Most of the homes I'd lived in let more cold/draft in around sealed double-paned windows.

Several years into living in our own butt-and-pass home with fiberglass insulation and mortar chinking between our logs, we're still "sold". The wind is NOT whistling through our chink zones, even in the strongest storm. : ) (Where we live, we do have relatively cold, windy and often snowy winters.) I can't presume to explain the author's comments, but building the way that is taught at LHBA is sound.

I would also add that the author's comments about coating your mortar with latex seems odd, since he admits that waterproof products promote the retention of moisture within the chink zone, possibly contributing to rot. It seems to me, from a common sense standpoint, that coating your "breathable" mortar with "unbreathable" latex pretty well defeats that purpose.

Best wishes-- Sara