My experience has been that the suppliers of engineered products will offer you a code minimum solution first, so called "value engineering". This is how the free market works, he is in price competition with other means and methods at this point.

They may ask or you may look over their proposal and see higher deflections or lower design loads than you would like. With something like this they will come back in moments with the next solution. We've moved beyond the minimum, it will cost more but will perform to the higher specification, it is you who will make the call to "over engineer". When you are at this point in the conversation the tech is on board, this isn't a price shopper, we are designing a good floor, roof, beam, whatever. He then begins tuning the design in that direction. He knows more ways of getting where I want to go, the process might become iterative for a bit.

For instance, if you get a floor of this clear span specified, the first option is likely to be a deflection of L/360, to code. That is about an inch of sag. I would ask for about half that, a stiffer floor. If you've ever walked on one of those long span stiff floors it is like walking on a snare drum, that's no more fun than the saggy floor. To calm that down make sure the underside is sheathed and you need more mass, "mass damping", a double subfloor is one way. Run the numbers with a double dead load and there is one way to a better performing floor.

As much as possible, that isn't a floor I would build without cautioning that they might not be happy in the end. Ah and another popped into mind from that class, because floor vibration is a function of not just the joists but if they are supported by spanning girders and headers, that increases vibration. Design them to a deflection of L/600 or less.

The way the engineering of these products is done from a liability standpoint they will engineer the beams or joist or trusses but they are no designing what it is supported by other than to give minimum bearing areas. For instance on 1akbig1bear's they engineered the beams and joists not the posts and foundation. That can give a builder a false sense of security, they aren't scrutinizing that part of your plan, they are designing their elements not yours. Keep this in mind as you design, generally you are the engineer of record, you are subcontracting that element of design.

Hey Redside,
Nice job on the cabin and excited to see the progress along the way. Curious as to the overall purpose of the cabin when complete? Weekender, Hunting, Fishing, long term plans?
How far off the grid are you and what transportation is needed to get materials to the site?
I'm in the same boat as I build my cabin on Kodiak in dealing with SBS, although very nice people the quality of the materials is not nearly as good as I would hoped plus it is very limited choices. Wait until you try to buy doors and windows, I ended up buying my two exterior doors for $185 apiece at Lowes and SBS quoted $535 each. The same goes for windows, their price was double at best as the high end over the counter versions Home Depot sold. I could actually buy mine in Seattle and ship them to Alaska for less than I would have paid at SBS.
Good Luck on your build...

OK, making progress but not posting much.  It was great taking that one week vacation in that other cabin with the light picture I posted above, but it took some time away from building.

I am trying to get to full dry-in and am getting close.  Cutting to the chase, I have most of the roof sheeting up and have started on the dormers:







After I got the rafters up as described in my last post, it seemed (to some at least, not really to me) that I should be getting the sheeting up right away (friends at work would ask each Monday, "got the roof up?").  But I knew the porch rafters and the barge rafters/lookouts would take some time.

The lookouts took a whole weekend.  The back wasn't so hard since they were shorter and I had the (temp) loft floor to stand on.  I actually built most of them first and then installed them into place (luckily my wife came to check out progress late Saturday since that was definitely a two person job).  The front one was much trickier as I had to build that in place, high up, and without a floor to stand on.  Technically it is not done since I need to face nail the barge rafters onto the lookouts (they are just temporarily connected now via toe-nailed screws) as there was no way I could get to the other side of those rafters until I get my deck made.  Pics:

Back:



Front:



Then I had the ends of these barge rafters to detail, which I did in conjunction with putting up the porch rafters.  I took this shot showing just how complicated that gets:



That's the front corner on the porch side.  That's before I added more straps tying the porch rafters to the main rafters, making them parallel to the porch rafter.  that is Four straps, plus structural screws in the the top, some nails, and then the "blocking structure" I put between each rafter.  Normally you would block with a 2x8 or something, but because the porch rafters meet higher up on the main rafter (I did that so that each roof plane is exactly 12 feet, simplifying sheathing, and allowing a full 4/12 pitch to the porch roof) this would have been 20" tall of solid blocking.  So I built a square of blocking to which I will nail 20"x22.5" OSB on the outside.  I left 2" gap at the top for the air channel for the cold roof.

Getting the 5/8" sheathing up to the rood wasn't nearly as hard as I was expecting.  I had tried getting one up to the loft before just after hoofing all 46 sheets into the cabin for storage under the tarps.  However, I think all that hoofing was why I had nothing left to move them any higher.  Once I was fresh, I could easily push them up a ladder to the loft, then slide them out the dormer holes.

Next steps are to finish the dormers and then getting the foam insulation on the sides so I can get the windows in.  Then do the front deck so I can finish sheathing that wall and get the windows/doors in there, too.  Then I'll be dried in. (yeah, I have to zip tape the walls, too; keep putting that off).

A few questions for the experts out there:

• Exterior foam:  Still trying to decide between the polyiso and the extruded PS.  The XPS gives me enough R value to meet rescheck, but doesn't come in 1.5" widths.  The polyiso comes in 1.5" and has higher R value but costs more.  But may save costs since I will have flexibility piecing it together with two layers of 1.5" rather than one layer of 1" and one layer of 2".  I.e. left-over scraps from the first layer could be used as needed on the second layer.  Any thoughts?
• Suggestions on how to hold the boards on prior to screwing in the furring strips?  I see Nathan's second-hand boards came with some nailing retainers already attached.  I won't have those.  Do I just put some temporary nails or screws so long as I put the furring strips up right away afterwards?
• I suppose I could do some of my own research on this, but it is customary or necessary to tape together the foam boards?  I've seen both on my cursory investigations.  The underlying Zip panels will be taped, so I already have an air barrier.
• Nathan: I saw you spent a lot of time evaluating loads from falling snow onto your mudroom roof.  I have a small (2'-3') drop from the dormer onto the porch.
   I wasn't planning on doubling up the rafters under there, but I still could I suppose.  Here's an earlier picture from when I was still installing the porch rafters.  Could sister those up with additional supports under the left side since I don't have the sheathing up there yet.  Not sure if that's worth it or not.
• IN that last pic, you can see I still don't have the last rows of decking on the porch floor.  That is because I haven't figured out how to bend the PVC flashing that I bought on Don_P's recommendation (note, good recommendation!)  I don't have a metal brake.  Would putting together a die like Nathan used for his aluminum flashing, and pulling it though that work?  I suppose I should just try (always lots to do), but wondering if there are any other suggestions.  I would need three bends since the flashing would start on the wall, go over the ledger board (two bends) and then extend under the decking so another bend to bring it horizontal on the joists.
• I like having a walk out basement, but don't like the expanses of parged-over block, so I would like to extend the siding over them.  The front part is easy, but I don't know about the sides.  The north side will be covered by the porch, so that isn't an issue.  But the south side is exposed.  Earlier pic: .  Since I will be applying exterior foam onto this wall, I will want to extend that and the furring down to all the areas where I will side over the blocks, so I need to decide now where I will do that.
   My question is whether it is possible to do a diagonal bottom edge of the siding.  I plan on using some sort of lap siding on, possibly LP smart side.  I have never seen such siding end diagonally, always stair step. I suppose there is a reason for that.  Is that my only option?

That's it for now.  Back to work.

I'm assuming there is an upper loft floor acting as a tie at plate level. I prefer a steeper lower pitch to get more useable floor area. Without engineering a steeper lower pitch has less horizontal thrust and then I tie the upper pitch with ceiling joists across that upper pitch, a structural ridge would work too.

Gambrels suffer from the same problems A frames do as far as the "tunnel effect" of only having lighting at the ends. I haven't seen too many visually pleasing dormers short of a full cross gable.

Follow the load path in the 2nd drawing over the garage door opening. The roof and loft floor would deliver load to the window headers. Those jacks are delivering point loads onto the garage header, then a uniform main floor load. That will probably be an engineered header like an LVL or similar, I'd point that out when asking them to size it.

I will call this "Barn 1 "

Do you framers see any thing that can be done better ?