Advanced framing, though decades old, is still not nearly as well known as it should be. The goals of advanced framing match closely to the desired outcomes of most tiny house builders, so I’d advocate for its wider use throughout the tiny house building community (DIY included, of course!). For those of you you have not heard of it before, or want to learn more, this post if for you.
Green Building Advisor defines advanced framing this way:
Advanced framing, also called optimum value engineering (OVE), is a framing system that aims to pare the amount of lumber used to frame buildings to the bare minimum.
The idea is by making a few adjustments to the way walls are traditionally framed, we can use a lot less material, improve insulation, and reduce waste. In addition to (and because of) the reduced lumber use, advanced framing has many potential benefits:
- Less lumber needed, so lower materials costs and lighter weight (great for THOWs!)
- Potentially lower labor cost/time and shorter build time due to simpler framing with fewer pieces
- Reduced environmental impact because less lumber is needed (fewer trees need to be cut down)
- Reduced construction waste (lumber can be used more efficiently because wall dimensions use exact 2′ increments)
- A reduction in thermal bridging and more room for insulation (because the walls and roof have fewer studs and rafters)
- Lower energy costs (due to better insulation, as noted above)
How is this possible and why does normal framing not do this already? Let’s look at advanced framing in more detail.
The main differences between traditional framing and advanced framing are as follows:
- Studs are placed 24” OC instead of 16” OC
- 2×6 studs used instead of 2×4 (more on this later related to tiny house building)
- Header hangers (Simpson HH header hangers) are used instead of jack studs
- Headers are insulated, and only used on load bearing walls
- Single studs are used at rough opening
- No cripple studs are used under window openings
- Corners are created with just two studs
- Single instead of double top plate
- Stacked framing transfers vertical load directly (between floors)
The diagram below illustrates these points and a few others. Notice the reduced lumber, especially around window openings.
One thing that’s important is lining up studs, joists, and rafters, so all the weight can be transferred directly downward. This eliminates the need for a double top plate.
You’ll notice that 2×6″ lumber is recommended. The extra width of the lumber helps account for the reduced number of studs and insures plenty of structural strength. But what if you don’t want to use 2×6 lumber for the walls of your tiny house? You want to save those extra 4 inches (two in each wall) to maximize interior space, right?
I am not a structural engineer, but I believe the general consensus within the tiny house community is that 2×4″ studs are more than adequate for tiny house construction with advanced framing, primarily because these are single story structures, and without a second or third story to support, there is much less load on each wall. Since the walls need to support the weight of the roof and nothing more, 2×4’s offer more than enough strength (and then some!).
I used advanced framing (with 2×4’s) on my house, and I’m very happy with that choice!
The reduced lumber allowed for more insulation with less thermal bridging, and reduced the overall weight and cost of the house. What’s not to like!
Want to know more?
Check out the following PDF resources for more info on advanced framing:
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Author: Alek Lisefski