Replies

1. 
   rjw | Dec 24, 2004 05:46pm | #1

   It is; it's just a longer and 'infinitely' wider bridge ....

   ---

   I don't know about yours, but my church isn't a hotel for the holy, it's a hospital for sinners

   ---

   Sojourners: Christians for Justice and Peace

   
   

   ---

   Edited 12/24/2004 9:47 am ET by Bob Walker

2. 
   Piffin | Dec 24, 2004 05:52pm | #2

   Technically, it is.

   Theoretically, at least, the massing of the logs creates thermal mass that helps compensate for this.

   And one of the worst problems that arises from the thermal bridging in a frame wall is that the cold spots following the studs will atract condesation, mildew, smoke residue, etc, making unsightly dark lines on a painted SR or plaster wall. That negative visual aspect is not a factor in log homes.

    

    

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1. 
   rjw | Dec 24, 2004 06:24pm | #3

   >>cold spots following the studs will atract condesation, mildew, smoke residue, etc, making unsightly dark lines on a painted SR or plaster wall.I usually see that when there are a lot of candles around.BTW, I have heard 2 theories for this: the one I like is the "Increased Impact" theory -- the cold "lines" lead to increased thermal currents which lead to more impacts from soot, dirt etc.The other is the condensation theory you mentioned.I think the condensation theory is the right one - I sometimes see soot ghosting where an entire framing bay" will be uniformly soot covered and, in ther attic I can see that section is missing its insultaion. [See attached pics: (One small version of the interior shot - and the interior shot has had its contrast increased to bring out the ghosting)]But I 'like' the increased impact theory - more elegant {G}I don't know about yours, but my church isn't a hotel for the holy, it's a hospital for sinners

   Sojourners: Christians for Justice and Peace

1. 
   Piffin | Dec 24, 2004 07:03pm | #4

   probably some truth to both theories. Where I saw the impact most seriously was in extreme cold weather, whether there were candles and wood stoves or not. I remember one house where it had been insulated with some sort of a pumped in foam that had shrunk back form the studs nearly an inch and down from the top by more like four inches. I went in to that house and it lookewd like an ex-ray to see the walls with the mildew pattern outlining exactly where the studs were, each piffin screw, and the insulation voids.

   The owners were first mystified with wonder about haunted house syndrome in a brand new house, then angry as heck after finding out what it would cost to rectify... 

    

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3. 
   xMikeSmith | Dec 24, 2004 08:01pm | #5

   peter.. a conventional log home with 8" logs has a nominal R-value of R-8 thru the log section.. and LESS at the joints...

    it is just one massive thermal bridge compared to an insulated wall

   Mike Smith   Rhode Island : Design / Build / Repair / Restore

1. 
   Piffin | Dec 25, 2004 03:48am | #6

   Mike, that depends on the species of wood too. IIRC, Pine is about R-.97, but cedar can go to 1.14.

   And the log homes I am seeing here on this trip to Idaho are using 14" logs.

   but in spite of correcting the details, you are right on the principles. It is tricky to seal joints against infiltration or wind driven water too.

   But there is something to the thermal mass idea. I have the same degree day approx as you and heat 2600 sq ft last year for a little over 600 in oil, and I bet my oil prices are higher than yours. I have R 28 in roof over 6x8 logs actual 7" except at seams 6-1/4" 

    

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1. 
   DavidThomas | Dec 25, 2004 03:59am | #7

   "But there is something to the thermal mass idea."

   Only if there is excess heat to carry from the day into the night.  Hot/warm days and cool/cold nights and then mass helps transfer the BTUs from where/when you don't need them to when you do (and for free).

   If it gets cold and stay cold, mass doesn't help.David Thomas   Overlooking Cook Inlet in Kenai, Alaska

1. 
   MikeSmith | Dec 25, 2004 06:40am | #8

   Merry Christmas !

   as you know... when you plug up one hole that makes the ones that are left that much more conspicuous..

    so .. log houses were always considered to be better insulated than frame houses until we had our energy crisis.. then the franchises like Lindal cedar Homes had to do some fast scrambling to keep from being fluhed down the toilet of obsolescence.

   a wooden section with an R-value of .97  to   1.14 per inch just wasn't going to cut it..

   unless .. it was the least of one's troubles..

   when we started doing heat loss calcs.. we'd increase the sections  and get  the convections and conduction losses way down.. but the air change losses were still substantial..

   if you hold the log wall section constant and acheive a true R-10.. that becomes very acceptable, if you can get the other losses  way down..

   seal all of the cracks..

    improve the windows...

   put a lid on the attic..

    stop the floor losses..

   pretty soon the biggest loss  left is the wall section  and that is  manageable..

   we don't live in Alaska.. our degree day design is about 6000 .. and in truth... our winter is 5 months..  so it's important not to sacrifice the enjoyable 7 months to the heating season of 5 months..

   it took us a couple years to figure this out and retreat from our concept of " homes-as-citadels-against -winter"...

   nowadays we use a lot more glass that we should for heat loss reasons..

   so.. i would guess that someone who WANTS a log home should get what they want , but realize that they are making a trade-off

   have you tried designing a log home that will comply with some of the current energy codes ?  what strategies do you use ?

    Mike Smith Rhode Island : Design / Build / Repair / Restore

1. 
   talkingdog | Dec 25, 2004 04:20pm | #9

   As for "log" homes that comply with the latest energy standards, I came across this one the other day, a SIP home with log siding. Neat hybrid concept, if all you want is the rustic looking exterior. I suppose you could install the log siding on the interior, too, and nobody would be the wiser. Eight inch SIP walls with log siding on inside and outside would work out to nearly 14 inches, in a manner of speaking.http://www.countryplans.com/raby.html

2. 
   Sphere | Dec 25, 2004 06:04pm | #10

   ayup..the little holes will actually whistle. and the logs can and DO get cold to the touch. The filling I am useing is 2" pink foam with greatstuff for gap and glueing.The foam gives me an r10 in the spaces, of course the tightly stacked newer log homes don't employ chinking such as mine. The last one I worked on had logs only 5.5" thick. My walls average 7.5" thick with up to 6" tall gaps (due to the dovetailed corners and really tall logs, some 16" tall).I am seriously thinking of a major change here, teardown the addition in the back, teardown the log half of the house and rebuild the logs on the addition foundation, add a single story addition behind that.Ofcouse, I'd have to bring in a temp. trailer for the reconstrction phase..but looking at the options, this may be the way to go. 

   Spheramid Enterprises Architectural Woodworks

   Repairs, Remodeling, Restorations. 

    

    

3. 
   Piffin | Dec 25, 2004 10:34pm | #12

   Howdy Dog! Some guys here don't believe me that a dog can talk.

   ;)

   You still in Japan?

   There are some other lit outfits that use a foam core and logs in/out split, but that never appealled to me as a substantial style or true log home. The SIP idea is structurally sound though and really good insulation. Thick log siding really uses up resources and still has the maintainance issues that other log homes have, but less of the energy issues. I like what I see so far, but slow downloading all those photos at that site.  

    

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4. 
   rez | Dec 26, 2004 12:00am | #13

   . 

5. 
   ClaysWorld | Dec 26, 2004 12:36am | #14

   What did you trim that valley shot#2 with- a beaver with cavities

   Oh now I get it, I got to the last bus shot and figured it out, it was a sawzall on a acid trip

   Edited 12/25/2004 4:40 pm ET by Clay

6. 
   rez | Dec 26, 2004 01:07am | #16

   Ya, I kept wondering if maybe I needed a new blade or something.

   I thought all the asphalt tar on the blade from the last three ridgevent renovations would have kept the blade lubed up good enough. 

7. 
   ClaysWorld | Dec 26, 2004 01:27am | #17

   I think your on to something---- like a nice supply of toothpicks for Cmas dinner.

8. 
   Piffin | Dec 26, 2004 07:18pm | #19

   Thanks, rez, for keeping us all on the bus

   ;) 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

9. 
   talkingdog | Dec 26, 2004 05:01am | #18

   Yes I am still a dog in Japan, but not a Japanese one,

   thankfully, and I can still talk.There are lots of ways to do a log home. Some of the
   log home "products" on the market don't bear much
   actual resemblance to the real thing. This goes for
   the cabin with 14 inch logs (these are real popular
   here in this country). So, I guess SIP plus log siding
   is not such an extreme idea. If you wanted to conserve
   on resources, I suppose you could create a very rustic
   feeling by using slabs from the mill instead of log
   siding. My own feeling is that almost all of the cabins
   being created today are too slick looking, logs too
   perfectly milled, etc. No milling at all in a true
   log cabin. Hewing perhaps. IMO, the real McCoy is made with logs that humans can
   manipulate without hydraulics (you should have a bad back
   after completing your cabin), let's say six or seven inches,
   and chinked with mud or other organic matter. It's an honest,
   rustic shelter, architecturally
   speaking a primitive archetypal structure. As an interesting side note, log cabins are extremely popular
   on these shores, especially with DIYs. Because of the
   seismic problem, any sort of wooden structure gets lots of
   metal holddowns and whatnot. However, this is not
   required with log cabins. Because they are so seismically
   stable, the explanation goes, there is no need to bolt
   everything member together they way it's done with
   other structures.

10. 
    Piffin | Dec 26, 2004 07:20pm | #20

    it sounds like the Japanese are now coming to the American style of resisting seismic forces. Their older 'ethnic' housing style was to built with piles and posts in such a way aas tolet the whole structure sway with the flow and remain staniding, and then replace the torn paper panels later. 

     

    Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

11. 
    talkingdog | Dec 26, 2004 08:42pm | #21

    Yes, the post and beam structure performs pretty well in earthquakes if the structure is not compromised by termites. Got a 1000 year old one right next door here.Actually, they do have their own indigenous log cabin type, used in granaries I believe, over a thousand years ago. Some of these are still extant. A very interesting shape to the logs, too. They were hewed to an isoceles triangular profile. When stacked, the point of the triangular log pointed outward, and the narrow base inward. So, I guess, from the interior of the structure, the walls looked like they were planked horizontally. Anyway, the corner detail for the stacked triangular section logs is really rather lovely. Must have been a lot of work. Would be easy to insulate such a structure with EPS foam board, too.

12. 
    rez | Dec 26, 2004 08:55pm | #22

    Talking Dog,

    That is really interesting. Is there any chance of seeing some photos of those structures. 

13. 
    rez | Dec 26, 2004 10:17pm | #24

    24441.1 is one old thread that contains a lot of data regarding Irfanview.

    You could use the search function with 'irfanview' typed in. It will take you to other threads sometimes discussing different questions regarding downsizing and such.

      

14. 
    talkingdog | Dec 27, 2004 08:52am | #26

    You can see the corner detail of this old log structure. I believe this is the oldest one in existence, built in AD 799. Dunno how they preserved it like this for so long.

    View Image

    Here is the structure. These are storehouses for religious images, etc., not granaries as I said.

    View Image

15. 
    Piffin | Dec 27, 2004 11:27am | #28

    Those photos aren't showing up.Can you do them as attachments? 

     

    Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

16. 
    talkingdog | Dec 27, 2004 04:48pm | #29

    OK, dunno what's wrong with my html.I just came up with the metaphor for these walls: Stimudent logs.First one is the detail, logs are probably original and the roof framing is looks recent.

17. 
    SamT | Dec 27, 2004 05:11pm | #30

    Dog,

    >>dunno what's wrong with my html.

    Geocities.

    SamT

18. 
    rez | Dec 27, 2004 05:43pm | #31

    Ah those pics are so much clearer than the word written visuals. Thanks. 

19. 
    Piffin | Dec 25, 2004 10:27pm | #11

    No, I haven't but if I did, I would incorporate the following:

    (please add to this everyone - it could make for a great thread)

    I would try to use plenty of foam in the basement level, such as having the lowest floor five feet in the ground with ICF foundation and radiant slab over foam.

    I would use the thickest log walls available and seal the joints as I laid them, effectively gluing them together instead of just adding caulk later. I would use kiln dried logs too ,so the movement of drying, shrinking, and checking later is limited. One good system uses bolts to draw the logs down tight instead of letting nature settle them with Mr. Gravity later on. The log movements thjrough the life of the home add considerably to the infiltration gaps.

    I would top the thing off with four inches of sprayed poly foam in the attic or with SIPs over the log roof structure ( most log homes have some amt. of cathedral cielings)

    I would orient to the sun with back up against the north winds and use landscaping to break the winds

    and like you mentioned, I would pay attention to the windows 

     

    Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

20. 
    ClaysWorld | Dec 26, 2004 12:45am | #15

    Sounds like your gettn ready to start a new project.

    The picture of the wood is great but there is no doubt there has to be a substantial tradeoff on performance to keep the survival of the stick construction.

     It is a nice, luxurious configuration.

     Happy holidays. Let reason prevail.

2. 
   hasbeen | Dec 26, 2004 09:31pm | #23

   I don't know the rate for heat exchange from log to air, but wouldn't it also be the case that whatever thermal mass logs might provide would also only be beneficial is the rate of heat exchange allows heat to be absorbed during the day and released at night?  As I said, I don't know how that works with log, but I do know that it works almost perfectly with 8-12" of masonry. 

   And then there's the annual tempurature pendulum you get from masonry, and even the soil under/behind masonry in some homes.  I don't see how anyone could get annual heat from a log (without burning it!).I'm thankful for the loyal opposition!  It's hard to learn much from those who simply agree with you.

1. 
   DavidThomas | Dec 27, 2004 07:41am | #25

   I wasn't proposigng that anyone get annual heat from logs. They don't get it from logs, masonary or anything short of thermal storage in ground below 10 feet or so deep.Ideally, for day/night temp swings, your thermal mass would be fairly conductive. So that BTUs could be stored and released from the entire mass. Wood's lower conductivity (versus stone, and, especially, water and metal) makes it less helps per pound as thermal mass.The log cabin argument would be: As long as you need to make walls, why not make the insulation, outer sheathing, and inner seathing in one shot?I don't enitrely buy it. There is some truth to it. And yeah, they look nice. But 2x6s, 4x8 sheetrock and 4x8 plywood are SO good at doing what they do, it is hard to beat.David Thomas   Overlooking Cook Inlet in Kenai, Alaska

2. 
   hasbeen | Dec 27, 2004 08:53am | #27

   I didn't think that you were proposing that annual heat came from logs.

   Perhaps I'm not calling it by the correct name, but I would disagree with you about annual heat only coming from far underground. 

   The first passive solar I built had a 4-5 ft high concrete wall that was painted black and exposed to lots of fall-winter-spring sunlight.  Behind it was decomposing granite.  On top of that was a concrete basement floor (lower level that we called basement was higher than the greenhouse floor, which was the lowest level).  Weeks of sun on the floor and wall heated the ground substantially above natural ground temp.  I'm fairly certain that there was a seasonal temp swing.

   Not sure if that gets my meaning across very well.I'm thankful for the loyal opposition!  It's hard to learn much from those who simply agree with you.

3. 
   DavidThomas | Dec 28, 2004 01:58am | #32

   I like your approach that altered the ground temps well above their natural temps in winter.  I agree that it can be done and should be done more often than it is.

   Dark (or light colors) for walls and paving make a difference.  Plantings, especially tall trees to the south block summer heat.   Decidious tress can block in the summer and transmit sunlight in the winter.  Trees to the north can block winds and reflect solar heat.  Coarse gravel or cobbles can cool to greater depths due to convective air movement.  An adit that climbs as it penetrates a hillside can trap summer heat, etc.

   But it sounds like most of the heat you got in the heating season was captured solar energy from the same heating season, albeit over a weeks-long timeframe.

   My point about deep soil was that if you want to store heat for 6 months or more, it has to be deep and/or very well insulated.  And, since you use that heat only once a year, the media has to be cheap.  Dirt cheap, you might say.David Thomas   Overlooking Cook Inlet in Kenai, Alaska