Log Home Seismic R Value 1

[msquared48]

Currently designing a log structure that is a real menagerie. Uses an Insulated foam sandwich panel roof with log and stud walls, TJI floor joists, glulamms, parallams, and an ICF foundation - a real hybrid. That said...

I saw the post by RockEngineer in 2006, but has anyone come across any more recent guidance than the 2006 article in Structure Magazine on the appropriate R value to use for log homes?

I heard a rumor that there was some new design guidance out there for log structures.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[RockEngineer]

I hope you find some more info. If you do let us know.

If I would have suggested a person to ask it would have been you. I am always amazed at your breadth of knowledge.

 

[PSlem]

http://www.loghomes.org/uploads/EnergyPerformanceWP_2010.pdf

 

[JoshPlumSE]

Don't know what R value to use. Maybe the R value for "other systems".

To me, the more important question is what is the lateral load path? I don't see a natural lload path for the lateral loads in a log style home. Though I know very little about them.

 

[PSlem]

Wrong R. I didn't read title close enough.

 

[msquared48]

I can't find anything more to date and neither can my sources, so I guess, with the range of 2.8 to 5.3 from the article, and considering the methods of joinery used in this structure, I am going to use a bearing wall system with an R reduced from 6.5 to 5.0 and see what happens.

Thanks all for checking, and the complement Rock.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

FYI all:

I did find out that unlike ASCE 7-05 or the IBC 2006, the IBC 2009 edition refers to a new publication, ICC 400-2007, that is available on the ANSI website below for $25.00.

I have not seen it yet, but understand that it probably does not address the R value issue. Apparently, it deals with Log Structure design and construction "guidelines", whatever those are.

http://webstore.ansi.org/RecordDetail.aspx?sku=ICC+400-2007

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[OHIOMatt]

http://www.structure1.com/loghomes4.htm

If you follow the above link, it will take you to a page that shows the structural requirements from ICC400-07.

At the bottom of the site, it does adress R and indicates that a value of 4 is reasonable.

 

[OHIOMatt]

Sorry, I read the site again. The R=4 reccomendation came from ICC400-05.

I have ICC400-07, and it does not seem to provide this value.

 

[ishvaaag]

"What is significant here is the log walls' average R-values was 44% lower than the frame walls" average R-Value."

http://www.100-mile-house-log-homes.com/the_logs.html

http://krex.k-state.edu/dspace/bitstream/2097/3909/1/SamanthaKessler2010.pdf

http://www.naturalloghomes.co.nz/pictures/Earthquake/LateralResistanceStructure2006.pdf

just googling it...