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I was wondering when someone would mention that Hometime log project. I’ve been building log homes in AK for the last 15 yrs. and I agree that there is a lot of spin and double talk on the subject of log wall R value. One argument goes that the logs only trasmit heat across the growth rings so there is less heat loss at the lateral joints where heat would have to travel along the rings. If that argument were true then flat sawn studs wouldn’t conduct heat through a frame wall. Rather than trying to support the claims of log wall R value with paranormal phenomena, I tell people that other wall systems can achieve higher R values. I think the best that can be claimed conservatvely is about R 1 per inch of log diameter. A deficit in wall R value can be compensated for overhead. By far the critical factor is controling in(ex)filtration. Like Jack said, people love log homes for their aesthetic value. I consider it my job to do the best I can with the log medium, and unfortunately millions of people will see the Hometime project and consider that as a standard. That place is going to be drafty! Some of their construction details (or lack of) leave alot to be desired.
In regard to Rob’s comment about real logs being the loosest ever, I say they don’t have to be. There are many skilled log builders (like me!) that scribe-fit natural hand peeled logs together with no gaps whatsoever and no chinking. Shrinking and settling can be accomodated and not ignored or downplayed like a ticking time bomb. The one house we tried scored well on a blower door test. Sorry but I don’t remember the numbers on that test, just that it achieved 4 1/2 stars on the AK Craftsman Home energy rating (out of 5). One more thing I should add is that I always ask the homeowners about their heating bills and they are very reasonable. For example: Anchorage, 4000 sq. ft, gas drier, water heater, outdoor hot tub always hot, total ’98 gas bill: $1024.
So you’re a log dog, Jack? I knew I liked your style. Greg
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I was wondering when someone would mention that Hometime log project. I've been building log homes in AK for the last 15 yrs. and I agree that there is a lot of spin and double talk on the subject of log wall R value. One argument goes that the logs only trasmit heat across the growth rings so there is less heat loss at the lateral joints where heat would have to travel along the rings. If that argument were true then flat sawn studs wouldn't conduct heat through a frame wall. Rather than trying to support the claims of log wall R value with paranormal phenomena, I tell people that other wall systems can achieve higher R values. I think the best that can be claimed conservatvely is about R 1 per inch of log diameter. A deficit in wall R value can be compensated for overhead. By far the critical factor is controling in(ex)filtration. Like Jack said, people love log homes for their aesthetic value. I consider it my job to do the best I can with the log medium, and unfortunately millions of people will see the Hometime project and consider that as a standard. That place is going to be drafty! Some of their construction details (or lack of) leave alot to be desired.
In regard to Rob's comment about real logs being the loosest ever, I say they don't have to be. There are many skilled log builders (like me!) that scribe-fit natural hand peeled logs together with no gaps whatsoever and no chinking. Shrinking and settling can be accomodated and not ignored or downplayed like a ticking time bomb. The one house we tried scored well on a blower door test. Sorry but I don't remember the numbers on that test, just that it achieved 4 1/2 stars on the AK Craftsman Home energy rating (out of 5). One more thing I should add is that I always ask the homeowners about their heating bills and they are very reasonable. For example: Anchorage, 4000 sq. ft, gas drier, water heater, outdoor hot tub always hot, total '98 gas bill: $1024.
So you're a log dog, Jack? I knew I liked your style. Greg
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Log homes are asthetically pleasing and are a lifestyle as opposed to the practical.
You're all right, when commenting on the inflated R values quoted on Hometime. The logs are a fair amount of mass and any mass capable of absorbing heat will slow the interior fluctuations.
But that house on Hometime better have a good recovery system because she's going to be drafty.
Although I have done log homes about 15 years ago, today anyone wanting us to design them a log home will have to settle for a conventionally framed house c/w insulation and the siding will be timberlogs instead. Did a large one last year and used 9 tons of 2 x 12 timberlogs and achieved the same asthetics as a log home but with real R20 walls.
Remember, our forefathers and tree mothers moved out of their log homes when they were able to build frame homes.
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Sorry, Gabe, but your log siding will never achieve the "same aesthetics" as the genuine article. Sort of like breast implants; pretty but fake and a much more expensive wall assembly. Freddy, thanks for your comments. Your insight is much appreciated here by many of us rational minded builders and DIYers, despite the loud and obnoxious noise of a few voices. After wading through the "Pressure Plan(e)s" thread I aquired a better understanding of in(ex)filtration and how that relates to my log walls and roof assemblies. I used to promote the virtues of VB and venting but am ready to discard that. Never did think much of FG. I have used mostly urethane, both sprayed and board, with and without rafters over the typical T&G ceilings in a log home. Do you think DP cels would fit into the log home/cathedral ceiling scenario? I think it could. Gene?
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Greg B. before you knock breast implants as not being as asthetic as the real thing, have you seen the ratings on Bay Watch?
As far as the cost is concerned, the method as described worked out to be nearly $20,000CDN less expensive than the "real log" on a 5,400 sq. ft. Bed & Breakfast.
Energy effeciency can be summed up by the 145,000 BTU oil fired direct vent boiler that keeps the entire house toasty.
*GregB, et al. In 1993 Ecotope, Inc., conducted a study for the Washington State Energy Office to affirm or deny the claims of log house pushers that the heavy mass of logs store heat in cold climates.Six log homes all in Idaho were analyzed and monitored for 16 months. The tests were performed by Ecotope and the Energy Division of the Idaho Department of Water Resources. Two of these houses were subjected to detailed tests to confirm the actual R-value of the log walls and to determine if the mass of the wall provided any energy benefits.One of the two houses was built using full-rounded logs and the second house used the Swedish Cope method which notches the underside of the logs.Using heat flow meters the technicians measured the R-value of the nine inch fully rounded logs to be R-11.1. The ten inch Swedish Cope walls measured R-9.5. The researchers concluded that the performance gain of the log mass was about 4 percent, hardly enough of an improvement to warrant a victory party.Why not with the DP cellulose Greg. GeneL.
*Gere et al. He is some additional information on log houses. In addition to the R-value measurements and determinimg how much, if at all, log mass contributed to the energy performance, Ecotope measured the leakage of the six log homes.Using both tracer gas and blower doors measurements they found the leakage rate of the six houses varied fro 0.19 to 0.48 air changes per hour. These numbers are typicasl of ordinary constructiont.Researchers found little leakage between the horizontal joints of the logs. However, they did find a number of leak-prone areas: fenestration frames, floor/wall intersections, roof/wall intersections especially at gable-ends. The study concluded that if log houses are properly built they can be moderately airtight.How does time affect the airtightnes? Ecotope technicians measured the airtightness at the beginning and end of the project. The intervall between tests was between 21-28 months.They found that the air leakage decreased slightly. GeneL.
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Gene, thanks alot for the info about the Ecotope study. It's good to know that a carefully crafted log home can stand up to technical scrutiny. Those trouble spots identified by the study are the ones that I've been developing methods to correct, and appear to have escaped proper consideration in the Hometime project. Specifically, splines and careful sealing of the settling log wall around the window and door bucks, providing an air barrier that prevents t&g ceilings from leaking warm air at the wall/ceiling joint, avoiding log wall gable ends, careful sealing of gable end log penetrations. Log homes are a lot more work! I'm starting a scribed log shell project shortly and I'm hoping to convince the owner to go with cellulose. All wood fiber! Hmmm, maybe celluloid windows? Greg
*Hello All,I am a radiant heating designer/engineer/installer and was wondering about your experiences with radiant heat in your log homes?Succesful/Not adequate......I am being asked to design alot of log home radiant systems lately and I want to make sure that I am providing these people the best comfort possible. Thanks in advance.Dave
*Dave, the majority of log homes I'm building get radiant heat and it works great. I have it in my own log home and have nothing but praise for it. Plus I like the absence of any visible heating equipment. The only caution I would make is to include it in the loft areas as well. Some people assume that the heat will rise to cover open loft areas like it does with forced air and regular baseboard radiators but it doesn't happen with warm floors. My experience is that it's cooler near the peak and gets warmer as you get closer to the radiant floor. A high temperature heat source like a wood stove will send hot air shooting up to the ceiling but the large scale gently warm surface doesn't. If you do rely on the radiant main floor to heat upstairs it might be uncomfortable. As a radiant system designer you probably know more about the technical details than I do. I've noticed that the newer systems seem to be pretty complex with the expensive manifolds with temp/flow adjustments to every tube in the system. Is all that really necessary? My system works just great without all that, just a number of separate zones and thermostats. I've seen an expensive and complex system totally out of whack, with entrance tiles hot to the touch, probably carrying the bulk of the load. I'm sure the potential exists to fine tune it to perfection, but the opposite is also possible! Anyway, radiant is the way to go. Greg
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I work with log home companies, mostly the swedish cope, norwegian saddle notch but full chink also, installing roof systems. These roof systems are Structural and Semi-Structrual (Stress Skin) EPS core with 1x8" T&G Pine interior face bonded directly to the foam core. This type of system installs fast and looks better than conventional methods (according to the customers and contractors that see it). The last project I did was 4300 sq. ft. which installed in 7 working days.
What this does for the U value of the log shell is what is relative to this posting I believe. The log companies have all sorts of roundy round info that relates to the mass theory mostly as far as I understand it. By using the EPS at 4.17/" as the roof inusulation which does not require any ventilation due the encapsulated air within the system. R-values of 34 (8 3/4") and 42 (10 3/4") are the most popular size of panels that we install.
Knowing that 75 to 80% of heat escapes through the roof due to rise, with this type of system that avenue is blocked efficiently. Due to this efficiency the overall (U value) of the log shell is raised. The cost of this type of system typically is the same as conventional methods installed and takes 1/4 or less time. Not bad for a premium product.
I apologise for not addressing the issue of logs efficiency as an insulator but I personally don't buy into it. Wood is a conductor. The mass theory holds only enough water to drown yourself in. Log Homes in general are apt to cost more per sq. ft. but those that want them don't seem to care. I agree with Gabe that an insulated log home is the best way to go, I personally live in one that performs very well. I realize that it is fake, in fact we call it "Faux Laug Manur" but it was affordable to build and maintain.
I have pictures of these systems but don't have the expertise to display them on this site. Will Email to any that want to see however.
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Greg-
Thanks for the info. As for the loft areas, I always suggest radiant for those areas and try to explain that HEAT DOESN'T RISE, HOT AIR DOES, but sometimes to no avail. That's OK, they'll call me when the loft area is cold that following winter.
As for designing a system with all the "bells and whistles" most systems can go both ways with the same end result....comfort!
The radiant industry is changing so quickly with the controls end, there are so many different options to go with today....outdoor reset control, injection pumping, reverse return... I could go on forever, but a lot of time the best way to got in order to make the sale and get radiant comfort for the homewner is on-off circulation.
Dave.
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On-off circulation....That's me. Now if the controls eventually cost fifty bucks and come all ready to go, then I'm in.
My way has worked well so far.
J
*See feature article at http://www.linkinglogs.com
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Rob: I built a log home with radiant several years ago and was very happy with both. They were large spruce logs with 2'butts and 1'tips. The R value most frequently quoted to me is ~R=1/inch.I don't have a scientific validation for that.The logs were fitted with the swedish cope method,and as is with anything, the final product is only as good as the craftsman doing the work.No chinking need,this was a very snug home,you literally could not slide a dollar bill into any joint.It was planned to allow for settleing (4" right off the bat when the concrete shingles went down) with spaces left above all openings and screw jacks under all the vertical columns.
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So my son and I are watching "Hoemtime" this morning ( we both like the tools and noise, what can I say). This is the one where they are building the monumentally outrageous "Lodge Style Long Home." And Dean asks the guy caulking (he called it chinking, but it looked alot like caulking to me) the logs about the R-value of the walls. Guy says the logs are R-12, and the air space created by the backer rod and caulk is R-15!! Am I missing something or should we all be building with caulk and backer rod? He went on to say that it is due to the thermal mass of the logs. They heat up and radiat the heat back into the room. From my experience, the heat only goes one way - out! I also formed the opinion that this particular type of log house (with real logs) has to be the loosest construction ever. Does anyone know the "Real Wall" ie - tested R value of these walls is? How are they from an infiltration point of view?
-Rob
*Rob,I have built mainly log homes over the years...Theyshould be built for the aesthetic and not for the energy savingsspin that all the sales is half based on at the "roadside" model homesaround the country.As the logs dry out over the years, chinking and leaking will be more or lessof a problem depending on the log manufacturer...I've noticed around here thatthe large log projects similar to the "Hometime Project" are fairingpretty well...It's a lifestyle thing,Jack : () )(ps- R-15 is probably very accurate given the sizeof the logs they are using. The thermalmass is definitely different than standard walls...loghomes like to be heated from radiant sources, such as woodstovesand hydronic baseboard and they are not good atnight time set back of temp. or warming up very quickly at 11pm Fridaynight for that weekend getaway...My customers thattried lowering the temp. way down while gone foundthat the walls radiated cold till about Sunday 5pm when they wereready to leave...I don't recommend log homes any more for second homes.