Advanced Framing Techniques

What is it:

Advanced Framing is a method of framing that minimizes weight and materials needed by putting lumber together in very specific ways to make it structurally sound in efficient ways.  Advanced Framing is gaining in popularity but is still a less commonly used method of house framing.  Generally advanced framing uses 2×6 lumber (generally Douglas Fir, exception to 2×6 below) placed 24″ on center so that sheet goods like plywood sheathing, OSB sheathing and drywall (which come in 4’x8′-12′ sheets standard) can be fastened to the structure on the perimeter, these are the walls ‘base studs’.  If the spacing was any less or any more than 24″ on center the studs wouldn’t line up on the edges of your sheet goods and could lead to more cuts and compromising the integrity of the material (sheathing is structural and offers less structurally in smaller pieces).  These studs are spaced on top of a ‘bottom plate’ which is how the wall is fastened at the bottom to the trailer.  A main difference, aside from stud spacing, between standard framing and advanced framing is that there is generally a single top plate at the top of the wall instead of the double top plate you see in standard framing.  Advanced framing is able to happen with a single top plate because it requires more planning and requires that roof joists be distributed in line with wall studs so that roof loads are carried directly down wall studs instead of potentially bearing at a mid point on the top plate between wall studs of standard framing.  Generally advanced framing is fastened with 16 penny (aka 16-d) framing nails which are 3.5″ long.

The exception to the 2×6 stud requirement is if you are building one story and only supporting the roof load, in that case 2×4 lumber is acceptable.

It has most commonly been recommended to use sheathing (either OSB or Plywood) that is at least 7/16″ thick in order to offer your structure enough shear strength.  There are alternatives to this such as additional strapping and T-111 siding which may be able to save you some weight while not compromising structural integrity.

Roof ‘rafters’ are generally 2×4 -2×8 lumber (Douglas Fir) placed 24″ o.c. depending on dead and live loads to accommodate and length of span required as well as amount of insulation desired.  Various roof styles require different size rafters.  It is important in advanced framing that your roof rafters line up directly over your wall studs for continuity.  It is fairly common for people to take certain aspects of advanced framing and not others.  If your rafters do not line up with your walls it is okay to do a double top plate as in Standard Framing so that it is able to carry the roof load over to the nearest wall studs without failing.  In addition to less lumber you are encouraged to use much more strapping and clips to reinforce your build with advanced framing.

After you have all of your studs spaced out at the appropriate distances you can start to add your door and opening (window) locations.   In the diagram below standard framing is on top while advanced framing is below, you can see the difference in amount of lumber used for the same wall:

framing

Standard framing on top, advanced framing on bottom

You notice there is a lot less lumber in advanced framing.  One other thing to note in advanced framing is how you connect interior walls to exterior walls, in standard framing you would tie them in with an extra stud so that you get a sturdy connection, with advanced framing you can use ‘ladder framing’ where you can brace with just a few pieces of blocking to attach to, this helps limit thermal bridging.

Each opening has a ‘header’ which collects the weight that would otherwise be carried by the wall studs and distributes it downward around the window or door desired.  With advanced framing you don’t have king studs and trimmer studs like in standard framing, you are able to use less lumber by incorporating the use of metal clips (generally by Simpson) to attach to a base stud.  You can add an interim stud to carry the load down if the window/opening is not on a 24″ module.  To create your rough openings for your doors and windows you generally take the size of your door/window and add 2″ to the width and height, this allows you room to level and square up your window/door as needed.   For windows you have an additional ‘sill’ which defines the bottom of the rough opening for the window.  The rough opening is generally about 2″ bigger than the actual window being placed, dependent on the size of the window flanges on the window (you need enough room to level and plumb you window in case the opening is slightly out of square but not too much that you cannot fasten the window flanges on the entire perimeter).  The sill is supported by cripples which are aligned with the base studs that are placed 24″ o.c. for your sheet goods.

Generally a corner condition where two walls come together in an advanced framed home looks like this:

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You can minimize the extra stud usually present by adding some clips to catch the drywall or whatever interior finish surface you are planning on having.  The 24″ dimension would start from the outside corner of  the structure to assure that you have a nailing surface every 4′ along the outside perimeter of the structure for your sheathing (which is structural).

Pros:

There is less lumber used than in that of standard framing techniques which leads to less thermal bridging and a more efficient building structurally and energy-wise.  While you may think it would be less expensive than standard framing because of the lack of lumber it is pretty much a wash because of the extra metal clips and strapping suggested.  Advanced framed buildings are slightly lighter weight than standard framing and so may be desired for tiny homes on wheels.

Cons:

This is less commonly known and understood than standard framing and has some critics that go along with that because it is less widely understood.  There is a significant amount of planning that has to go into the design of your structure to insure that all of the members are attached and located appropriately, there is less room for error in construction.

Tiny House Specific and Regional Considerations:

Advanced framing by nature incorporates a lot of the additional structural measures you would want to take when building a house on wheels with any kind of framing (strapping, hurricane ties, etc.).  In most cases it is most desired to use 2×4 lumber rather than 2×6 lumber to maximize your interior space in a tiny house, the requirement of one story can cause issues if you intend to have a loft space (since that is now supporting more than just a roof).  You can add extra structural measures, such as using rigid or spray-in insulation which actually adds structural value to your walls (making them up to 150% the strength of just a stud wall) to help accommodate a loft while still using 2×4 advanced framing techniques.   Additionally you will need to secure your walls solidly to your foundation using a minimum of 3/8″ lag bolts (recommended at 24″ o.c.).  It is also recommended to add Simpson Hold-downs at the front corners (minimum).

Wall, roof and floor thicknesses may vary based on the amount and type of insulation desired.  Typically they are 2×4 construction but in some cases more depth may be desired for a greater R-Value.

This is a collaborative site, if you have something to add/correct leave a comment!  If you have some words of wisdom on any of the methods mentioned feel free to share in the comments!

For a list of definitions please visit the definitions page

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About Macy Miller

Macy Miller is a Rocky Mountain native and the creator of MiniMotives.com. As a LEED accredited architectural designer she is a passionate promoter of good design, healthy living, and the tiny lifestyle. In 2011 she started construction on her 196 s.f. tiny house where she has been living with her partner, James, daughter, Hazel, and dog, Denver since June 2013. She and her home have been featured on Yahoo News, Time Magazine, Dwell Magazine, NPR, HGTV’s Extreme Homes and many others!

12 thoughts on “Advanced Framing Techniques

  1. Genevieve

    Thank you!!!

    I’m at exactly that point in my TH design & plan where I’m about to sit down and draft my framing. I’ve been trying to research a simple explanation of Advanced Framing and coming up short, or with automatic poo-poos from professionals I ask for advice (I’m building my THoW myself). This article makes so much sense. Thank you so much for providing this well-researched and well-written clarification of it, Macy.

    Reply
  2. Cheryl

    i have a question! In my design, because of window placement, the distance between my wall studs can range from 14″ to about 22″ – so I’ve lined up the floor joists and the roof rafters with the wall studs, and it looks fairly even on paper. But, like I said, the actual distance between the studs is not exactly even. That also means that a sheet of plywood will be just a little too long, if I want the seams on an existing stud…

    So my question! Should I leave the plywood full size (my preference) and just add an extra 2×4 stud where the seam is? Or would it be better to cut down the plywood slightly to make it fit on the existing studs?

    I won’t have a loft, but I’m still more concerned about strength than I am about thermal bridging, so I’d really prefer to leave the plywood full size and add an extra stud, but I’m curious if that’s the best choice?

    Reply
    1. Macy Miller Post author

      I would definitely suggest leaving plywood as whole as possible, the smaller pieces do not have the same shear value and plywood is structural! (sometimes people forget that part, I know you are not one of those people though 🙂 ) I always suggest laying out your studs for structure first and then adding windows and additional studs as needed for openings, if you want to save studs you can lay your windows/openings out on the structural (base stud) intervals but I wouldn’t skip those ones and try to use window opening studs instead. great question and I am sure feedback will vary, I HAVE seen plenty of tiny houses built ‘the other way’ but its not ideal in general!

      Reply
  3. Carmen Scott

    We are considering using the siding as sheathing for our tiny house. We will be using T1-11.The framing is traditional using 2x4s 16″OC. Will this compromise the strenght? We are using Huricane clips and metal strips. The floor and framing will be bolted to the trailer every 4 ft

    Reply
    1. Macy Miller Post author

      Follow the suggested nailing patterns with the T1-11 siding and you’ll be fine. I always suggest bolting the structure to the trailer every 2 feet, I’ve seen others suggest 6′, in reality you are PROBABLY fine at 4′ but I still feel obligated to suggest 2′! 🙂

      Reply
  4. Cheryl

    Thanks Macy! It makes perfect sense when you say it, and that’s what I was thinking, but I’m glad to have confirmation that it actually is the “best” way to handle it. And I mean best as in, what smart people would choose to do, given the current information available!

    Reply
  5. Sue

    I’m not sure if you will see this question to answer it but I have been told a good inexpensive option for siding is T1-11. Is that a good choice or is there something else comparable in price that I could use? I have seen comments elsewhere that it looks cheap and that’s not what I’m going for.

    What do you think about Board and Batten or metal?

    Reply
  6. Macy Miller

    It is a pretty cost effective material, we did use it on our shop/garage. It is pretty limited in appearance and looks to me like the cookie cutter homes, You can dress it up with some battens and probably make it look alright, it’s personal preference at a point honestly! I tend to agree that it ‘looks cheap’ but I don’t really like materials that are made to look like other materials. It tries to look like wood siding but you can tell if you are really looking… that may be something others easily ignore 🙂

    Reply

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