Question about Timbers projecting through SIPS

[jb9]

Hello,

I am curious if there are any guidelines or best practices regarding extending a timber through a SIP for the purposes of creating a support.  In particular, I am wondering if a bent girt or other member could be extended through a SIP.  In log construction I see this from time to time but I was curious if it can done with timbers. Also, it does seem that it might potentially expose one's frame to the elements a bit more than if it were fully within the SIPS.  Basically, I am trying to understand how porches, carports and entryways are "tied in" to a structure fully enclosed by SIPS.  I am considering all three of the aforementioned elements in my design and haven't quite figured out how to integrate them.  My preference is to be able to have the frame extend into these elements.

Thanks in advance.

[Jim_Rogers]

Normally we try as best we can to not do that at all.
There are other solutions to porch supports.
When I designed my partner in the tool business's retirement home, he wanted sip walls and a front "farmer's porch".
What we did was make most of the porch self supporting. We put piers beside the foundation to support external porch posts that will stand next to the house wall. This is one way to do it.
Next to support the ledger plank/timber along the house wall, we have instructed the sip company to embed a plank inside the sip for the lag bolts to lag into from the outside, without ever getting into the heated environment of the house. This prevents the hot/cold condensation factor so that no moisture will condense inside the sip and cause any rot.

Another alternative is to put on an external "bracket" to the outside of the house. Again lagged on to the wall to an internal lag timber.
You need to work out all these details with the sip company when you discuss your project with them.

Here is a shot of what I mean about an internal support holding up an external bracket:



 

Jim Rogers

[S.Hyland]

I'll second Jim's advice heartily. A timber traveling through a panel is major thermal break, as well as being hard to seal well. It also can become a pathway for water etc to reach the inner frame. I one absolutely had to do it I would use EPDM gasketing all the way around so that it can respond to seasonal changes in timber size. Best to avoid it altogether though.

[witterbound]

I've seen sips with pockets cut out to support timbers for a porch.  I imagine there is a header or something imbedded in to sips, but not sure. 

[jb9]

Thanks for the helpful information Jim!

I have been speaking with a SIPS manufacturer who confirmed that in the design phase, they can basically precision cut out sections of EPS and then slide in a stud or timber where needed.  The individual I spoke with also said that his panels come with pre-cut horizontal chases at 16" and 44" and pre-cut vertical chases at 4' on center.  I always thought that the SIPS did not have all these features so I learned a lot in the past few days.  I spoke at length with an electrician today as well who said that low-voltage wiring (think LED) needs to be separated from traditional wiring so I wonder if the chases have two separate channels.  Something else I will need to ask.

Sorry to veer off topic, but I wanted to share what I learned as I try to maximize what I can achieve with my SIPS.