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The Pacific Northwest National Laboratory recommends to use a very stripped down framing method for windows & doors; namely: eliminate the jack stud and hang the header board using tie plates, and reduce drastically the number of cripple studs under the sill:

jackless framing

How common is that style of framing nowadays? What are the limitations, in terms of (local) code? Any recent book that would present this style in details?

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  • Besides saving ~30% of the wood needed, wonder if builders will pass on the savings. Code can be quite local as to what is allowed, but seems like it comes from the government so being allowed is almost a given.
    – crip659
    Commented Oct 14, 2022 at 21:46
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    I'm not sure how common that type of framing is. I've always used the traditional king/jack arrangement. But, the less wood there is, that is replaced with insulation, the better the insulation property of the wall.
    – SteveSh
    Commented Oct 14, 2022 at 22:03
  • Drawing is missing the details on the top, which is why you need all that stuff on the bottom.
    – Mazura
    Commented Oct 15, 2022 at 16:29
  • @Mazura: Not sure I understand; what are the missing "details" and the additional "stuff"? :)
    – Michaël
    Commented Oct 16, 2022 at 21:05
  • Didn't realize it showed an LVL in dark brown. Shouldn't have a 2x4 laying under the header, labeled header. And it because it never works out like that; there's always some stupidly short cripples above the header. And you can't do that on the 2nd fl. : "Windows above 72 inches from exterior grade are required to have a sill at least 24 inches off the floor to meet 2012 IRC requirements," diy.stackexchange.com/questions/83794/… - I've no idea what the load bearing of a tie plate is and never seen one holding up a header.
    – Mazura
    Commented Oct 16, 2022 at 23:00

1 Answer 1

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Advanced/Optimal Value Framing isn't ubiquitous, but it is reasonably known

The technique you are talking about was originally called "Optimal Value Framing" by the NAHB (yes, that NAHB)/HUD team that came up with it, but is more commonly called "Advanced Framing" nowadays, and is permitted in most cases by the IRC R602 prescriptives for wood framing, provided 2x6 studs are used for any assembly that is supporting more than a roof and the assembly as a whole is detailed correctly, primarily with regards to the alignment of joists and trusses with the structural members as well as the way the top plate is joined together and how the headers are set. (The only case where R602 doesn't permit the full Advanced Framing package to be used is on the first story of a three story house unless you're able to use the alternate stud spacing table.) BSI-030 provides a detailed breakdown of what's going on that's more accessible than the Code provisions.

As to how well known it is now? That's going to vary by your area, but it's something that's been discussed in high-performance-construction and building-science circles for some time now due to its inherent thermal advantages over conventional stick built walls, so high-performance builders (think Net Zero and Passivhaus) in your area should have at least heard of it, even if they use a different wall construction themselves. Production builders and finish-focused custom builders may or may not know it at all, though, and some structural engineers and even a few suburban AHJs still aren't acclimated to it, with the occasional protectionist suburban building code requiring 16" stud spacing for stupid parochial/political reasons.

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  • I Enjoy your answers.
    – JACK
    Commented Oct 15, 2022 at 13:30
  • "the assembly as a whole is detailed correctly, primarily with regards to the alignment of joists and trusses with the structural members as well as the way the top plate is joined together." - which is missing the fact that the header needs to be an LVL (or equivalent) and cripples above it supporting the top plate, which require jack studs to rest on, which require king studs next to them. The 'extra stud' is a drywall nailer and is where insulation belongs and should be caulked.
    – Mazura
    Commented Oct 15, 2022 at 16:25
  • I've seen +100yo non-crippled window openings that lasted just fine; just not how I'd do it though. It should be unquestionably good for someone who's 300 pounds, holding something that's 200 pounds, no problem.
    – Mazura
    Commented Oct 15, 2022 at 16:26

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