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Kiln dried Cedar cabin logs

Started by blkhillsvt, January 04, 2010, 01:29:36 PM

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blkhillsvt

Does anyone have some advice pertaining to kiln dried cedar cabin logs vs. green in regards to advantages/disadvantages. Obviously kiln dried are not prone to crack or shrink, or are they? If someone was to use semi green cedar what could potentially happen?
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Jeff

1. Kiln dried are just as prone to splitting and cracking. You can't avoid it. I think placing cedar logs in a kiln, and forcing the drying, would only speed up the inevitable.
2. I don't believe it when they say they can dry the log in the kiln. It would take forever.
3. Cedar dries plenty fast on its own.
4. If they say it for bugs, I say Cedar has a natural resistance to bugs.
5. All log home logs shrink eventually and that needs to be addressed in your construction methods. Cedar should shrink less then pine or other softwoods.
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Cedarman

What Jeff said.  I think that kiln drying would make the logs crack more than stacking outside and letting nature do its thing.  We logs  (6"x6" )  that were growing 2 days before we sawed and put them in the top two rows of logs.  No problem.  The only cracking we have is big enough to put a fingernail in.  ERC stays straight when drying.  The teflon coated screws they have now will suck any bowing out when you put them in.
Can't add anything else.
I am in the pink when sawing cedar.

fireman05

I regularly KD cedar and pine 3x6's and mill them into t&g cabin logs for small hunting cabins.  The key seems to be to dry them very slowly and I also use ratchet straps to keep the piles tight to reduce twisting etc.  You will still have some splitting in the timbers and I have found this to be true especially when you dry too fast and if I dry below 10-12% mc.

I havent had the timbers shrink more once they are dried, but they will swell if left unprotected which causes my t&g to not fit properly prior to installation.
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CLL

Cedarman is much the wiser than I on this subject, but I will say this. I have cut ERC in the summer and in less than a month they weight 1/2 of what they did when cut.
Too much work-not enough pay.

LOGDOG

I think there may be an exception to the cracking if they're dried in a radio frequency kiln. Supposedly the cracking is dramatically reduced using that technology. It's expensive though compared to conventional methods so the odds are fairly good that the kiln dried logs you may get probably weren't dried in an RF kiln. Google or bing "Radio Frequency Kiln Drying or RF Kilns" and you should come up with some info. I know there's a place in the Northwest running them and they do large dimension fir and cedar. I may see if I can track them down again. I f I find them I'll post a link here if it's ok with Jeff. I can't remember what the rules are on posting links to outside sites. Maybe someone can remind me?  :)

LOGDOG

Edit: Here's a link to one: http://www.beeretimber.com/architectural_timbers.htm
and another: http://www.arcwoodandtimbers.com/kiln/index.php

It gives you an idea of what to look for maybe and what's available just in case you hadn't heard of it before.

barbender

Is that like a big microwave or what? With the cedar logs, or any horizontal wood, it doesn't matter how dry you get them, they will still settle due to compression across the grain. I don't know about ERC, but our white cedar up here has a very low moisture content on the stump, kind of odd considering it grows in the swamp.
Too many irons in the fire

LOGDOG

Yep Barbender, essentially like a big microwave. It drives the moisture out from the center and out the end of the log according to the commentary on the site. They can get a beam to 10% moisture content through and through in 10 days and 12% in 4-5 days - regardless of the size of the beam. Not cheap, but definitely effective. Look at the photo gallery on that Arc Wood and Timber website and tell me if that's not some beautiful wood. There's still some visible checking in some of the beams but at least the shrinkage factor is decreased from the get go.

LOGDOG

beenthere

Quote from: barbender on January 07, 2010, 10:38:27 PM
..... With the cedar logs, or any horizontal wood, it doesn't matter how dry you get them, they will still settle due to compression across the grain. .........

  The settling is due to shrinkage from loss of moisture below the fiber saturation point.  Doubt there is any compression of the wood.  :)
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LOGDOG

Quote from: beenthere on January 07, 2010, 11:04:16 PM
  The settling is due to shrinkage from loss of moisture below the fiber saturation point.  Doubt there is any compression of the wood.  :)

I'm with Beenthere on this. Think about all the train trestles across the country built from wood. If there were much compression of the wood it would certainly happen under the hundreds of millions of pounds of trains and freight passing over them and would certainly make for an eventually rickety structure. But there are still old trestles all over that are in great shape. Beenthere hit it on the head.  ;)

LOGDOG

Kansas

The house I built this year was put up with milled logs from cedar 6x6's. They came out of west-central Missouri from the Amish. They said they air-dried the logs for about a year, then ran them through the moulding machine. They also were the ones that actually put up the log portion. They seemed unconcerned about shrinkage, as far as around windows and doors and such.  These went up in may, and so far I can't tell or see any problems with them. I did check the moisture when the logs arrived, and they were down around where I would expect them to be. I think I would just air dry the way they did, rather than kiln them.

Cedarman

CLL is right that cedar will lose a good bit of weight, but compared to other woods, not near as much.  Most of the moisture is in the sap wood which is milled off to make a cant.  Heartwood of green cedar is in the mid 30 per cent range moisture. 
We left spaces over doors and windows when we built our house just in case.  The largest crack in any log in our house is fingernail thickness. Nothing to worry about.  Built in 1991. My brother who used white pine logs and let them dry for several years outside has cracks an inch wide. Some logs are 16" in diameter.  Doesn't hurt anything as they are internal.  He used 7x7 ERC for the walls and he has no cracking in them bigger than a fingernail.  He let them dry about a year before putting them up.  ERC shrinks and bows so little that it makes it a great houselog.  My brother did complain that they did shrink a 1/16" in length over 8'.
I am in the pink when sawing cedar.

easyEric


Kansas

Something I am trying to figure out. The builders used 10" screws or so to pin the logs together. If the logs did shrink, wouldn't they gap between the logs, rather than the whole wall settling? I checked this morning, while i can see what possibly is a very small gap on the inside walls, I cannot insert a pocket knife blade between the logs. On the outside, the caulk shows no sign of pulling away, although I assume that would be pliable. I would think the screws would keep the logs seperated and held to the same height even if they did shrink slightly. Just thinking how this all pertains to the windows and doors fitting.

easyEric

 My first post!  Had a customer that built a white cedar log home from self-harvested logs. He scribed the corners and left a gap for chinking between the logs. He had a long term plan, he assembled the log portion and put the roof on and left it for a year to settle and shrink. He built in more than a foot of vertical allowance for shrinking and every time I stopped in it was descending right on schedule. There is very little cracking in the cedar but he used seven 34' white pines I supplied  to tie the top together which cracked a bit worse and were prone to blue mold. All in all looks great and he has lived in it several years now.

barbender

I guess what I was getting at is wood will compress perpindicular to the grain, but not much parallell to it. That's why the train trestles are not settling- vertical wood. Anyone that has ever disassembled a log home shell can tell you how much the corners have compressed, where the weight is being bore.
Too many irons in the fire

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