Hello. New to this forum and I hope to find some insight and help from here. Thanks in advance! :) I am building a 16x24 "interior dimension" cabin off the grid using ICF's. Pretty familiar with the ICF construction, but sure I'll need help on that stage as well. To my first question: With an interior span of 16 ft, I'm wanting to have a 12/12 roof pitch with a small loft and vaulted ceilings on the non-loft end. What would be my best approach to achieve this? a.) engineered scissor/attic trusses b.) timber framing Thank you and Merry Christmas!

Sounds like a good application for SIPs.

Wow!!! Never thought of sips, but now that you mention it, it makes complete sense. Thank you! Any references(Links) to where to get some and installation process, etc?

Where will you be building?  Some of us may know of a SIPS company reasonably close.

This looks similar: http://users.chartertn.net/dhrivnak/sip's.htm

We have 10 acres in Eureka Springs, AR out by Beaver Lake. This is an "out-of-pocket" DIY project for me and my wife and a few buddies here and there. We're on a tight budget, hence the size, but want to build structurally sound and low maintenance for the future. This will be our home. I'm a tile contractor by trade, but have done all stages of building and know how to use a tape measure. Also there are NO building codes in our area. Thank you Jonr for the link. I read through and bookmarked the page as well. Thanks for the replies!

Oh yea Alton. Good luck at the BCS National Championship Game!!! I went to LSU. GO SEC!!

NOARK Enterprises in North Little Rock is a manufacturer of R Control SIPS in this area.  I purchased my borate treated underslab EPS insulation from them.

http://www.noarkrcontrol.com/

I'm currently building an ICF walkout basement on the banks of the Arkansas River near Pottsville, AR.  I'm currently ~5' high with the foam and rebar and will start building my bracing tomorrow.

What thickness ICF wall are you planning on building?  Creating a 16'x24' interior will result in an odd sized exterior and can result in quite a bit of material waste since most ICFs are sized to accommodate multiples of 2' or 4' on the exterior.  Have you decided on the type of ICFs that you will be using?

Exterior should be 18x26 using ARXX 11 1/2 inch forms with 6 1/2 concrete core, right? Correct me if I'm wrong please. I still have to wager the cost of using SIP's as opposed to 2x8 rafters, ridge beam and Advantech decking. I like the Advantech decking as opposed to the OSB, so still unsure. What is the cost per square ft of SIP's. I've figured around 730 sq/ft will be needed for our roof. Thanks I'll start a thread with pictures soon so all can see our progress. Dirtwork, septic, and well are done. We actually have ICF footers in place for a house that we can't afford right now. It'll have to wait to be built after the "cabin" is completed. We don't want to run out of money and have an uncompleted house.

greetings from Lawrence, Kansas

have done similar projects in Colorado but with much higher snow load.

there the SIPS made sense although costly.

your application I would be tempted to bump up to 2 x 10
simply to provide more insulation space for blown-in insulation
from Central Fiber in Kansas.

agree with above use of 6 1/2 inch core ICF.

Hi Cooshadow, if you are on a tight budget and if you will do all the work yourself, traditional 2x10 or 2x12 wood framing is the way to go in my opinion.
You will also need to do the insulation with R30 or R36 fiberglass yourself and this needs to be done very meticulus, without to many gaps/leaks for airinfiltration.
The way you will save a lot compared with SIP's
The size of the box is not that big to take this on for a first project, so expected techincal issues should be minial.
Except for the vaulted ceiling in the loft, code probably requires some collor ties to keep the rafters togetter even for 12/12 pitch where the outward forces are less then for 6/12 or 8/12 pitch.
The collar tie normally sits somewhere around 1/3th of the roof hight measured from the top to be effective.
Also don't forget the roof vents before you put in the insualtion.
Spray foam insulation is an other option but .... you guessed it, more expensive.

Yea, It seems SIPs might me a little spendy for us to afford. Was thinking a 3 1/8 X 15 1/8 GluLam with 2x10 rafters and R30 fiberglass or "blown-in" insulation like ecoarchitect suggested. There are no codes where we are, and we're trying to avoid collar ties all together. The loft should be fine considering the 2x12 floor joists will "complete triangle". Shouldn't I be able to get away with capping the forms with a treated 2x12 bolted to the embedded treated 2x6 top plate and hurricane clips on the rafters and not have to use collar ties in the "non loft" area?

Pretty cool video of a time-lapsed 16x24 SIPs cottage construction. http://www.youtube.com/watch?v=N3TaHR8l-N0&feature=related

Why embed a treated 2x6 in the wall forms if you are going to cap that off with a treated 2x12?  Why not just strike off the concrete level with the top of the forms, wet set your anchor bolts, then bolt the treated 2x12 directly to the top of the wall?  If you are going to rely on that 2x12 for support directly over the foam, you might want to consider taper top forms or cutting standard ICF forms at an angle on the inside top edge such that you have only ~1" foam thickness at the top edge.

Another idea for stick building your roof is to use 2X8 rafters then run ripped 2X4s perpendicular to the rafters 16" oc.  This would likely be less expensive than 2X10s and would give you ~9" for insulation and provide a thermal break everywhere except at the point where the 2X cross (like the Mooney wall).  Packing this area with blown cellulose would give you the most R per $.   You could leave the blocking out over the wall and have the cellulose installer blow in the cellulose from the eve since your roof is so small.  With the building construction slow down, you could probably find a hungry insulation installer to blow this in for equal to or less than you could buy the cellulose and install it yourself.

For the floor joists, I would consider 9-1/2" engineered I joists - straighter, stronger, and easier to handle than 2x12 lumber.  Heck, I would even consider using these I joists for your rafters.  These are a commodity item at most building supply centers.

Here is some design info for TJI Joists.  TJI-230 @ 16" oc should work for both your floor and roof.  See floor detail H3 and roof details R5 and R9 for possible mounting options.

http://www.ilevel.com/literature/TJ-4000.pdf