Cypress Sill log

[jrkimroxie]

Is a 6"x12"cypress timber acceptable as a sill log if supported on 8' centers. 32' on all 4 sides and 1 support down the center at 16'. The roof will be free span trusses so all weight is transferred to exterior walls. The exterior walls are 6"X12" SYP.

[Jim_Rogers]

That's real hard to say without understanding the complete picture/design.
Is the 6x12, 12" tall?

And is it holding up 6x12" log walls? with supports 8' on center?

I would think that you're going to need more supports than 8' apart.

Jim Rogers

[jrkimroxie]

A little background. The cabin will be in the mountains in AR, I spent 2 days with a excavator and a breaker hammer attachment to create the 3'L x 3'W x 2'D holes every 8 foot around the parameter of the 32'x32' cabin. These "holes" received around 600' of rebar that was drilled/driven into the rocks and also a 12"x12"x1/2" steel plate that was welded to the rebar. From that plate I plan to weld either H-beams or sq tube for my "pilings". On top of the pilings there will be another 6"w x 12"l x 1/2" plate welded for the sill log to rest on at 8' intervals.

    

[Jim_Rogers]

Well, it looks like you've got a good base.

But again it all depends on what you put above the sills that will determine if they are strong enough to hold it up.

Jim Rogers

[jrkimroxie]

The walls will be 6"w x 12"tall SYP. I'm looking to use 6"w x 12"t sill logs, and wondering if cypress is acceptable on 8' supported centers? I finally found a mill that will cut up to 40' long, but he primarily logs cypress, so that's what he has available.

[beenthere]

jr
That is a beautiful view. Going to be your home?

The walls will be 6"w x 12"tall SYP. I'm

Not following the 6 inch walls that are 12 inch tall SYP.  typo??

New growth cypress is not really know for resistance to decay, like the old heartwood cypress. So that should be considered in your design.

[jrkimroxie]

Yeah, that should have read the wall logs will be 6" thick and 12" tall

[Jay C. White Cloud]

Well it looks like you have a plan, and have thought about it much.  I have the same questions/concerns that Jim has, and would need more information.  It you have modeled this from an old and established vintage frame, built the same way you are doing it, then you have some assurance of success.  If you have a PE look at it (strongly recommended) then you will know for sure.  I don't think I could speak to your plan beyond that, as I have more questions than answers.  I can say that the continuous length is much less important than the type of joinery, support spans, span member sizing, and general design as it relates to overall architecture.