In green building circles, 24-inch framing is widely seen as being a good choice for many reasons. But the consensus is not unanimous (as you'll see below), and this demonstrates that building techniques are often a matter of builder or homeowner preference rather than being clearly right or wrong.
This discussion started with a question from a reader who wants to build a green home in Altadena. She wrote:
Some green homebuilding books recommend the "advanced wood-framing technique" of setting 2-x-6-inch wall studs 24 inches on center (rather than the standard 2-x-4-inch studs 16 inches apart). They indicate that this approach saves 20% of lumber used and is stronger. I was wondering if you have ever heard of anyone doing that in their Los Angeles home and if it would considered structurally weaker or stronger for an earthquake-prone location like L.A.?
Click below to read their answers.
Here’s the response I got from Devon Hartman, a principal with Hartman Baldwin Design/Build in Claremont:
Using advanced framing techniques is a superior way to frame for a number of reasons. First of all, it uses way less lumber and saves lumber resources and money.
Secondly, wood conducts temperature about four times faster than insulation. Why is this important? With conventional framing, there is way more wood in the wall cavities conducting heat four times faster from the outside to the inside (or vice versa, depending on the season) than with advanced framing techniques. This loss or gain of heat increases energy costs. And reducing energy cost is always our primary focus.
If you want to build a “green” home, then the number one issue, in the long list of things to consider, is energy conservation.
Two good websites to check out are Architecture 2030 (where there’s a great discussion on coal and the building sector’s role in global energy use) and the U.S. Dept. of Energy’s Energy Efficiency and Renewable Energy website, which includes a description of advanced framing techniques. The technique is approved by the International Building Code.
As for earthquake safety, the normal hold-downs, clips and shear panels provide resistance to lateral movement.
The major problem with these framing techniques, however, is that the home you design must be designed with these techniques in mind from the beginning.
And Devon’s last statement leads us to the response from Alon Toker, president of Mega Builders in Chatsworth, who is generally not in favor of 24-inch framing. And here’s how he explains it:
On balance, I’ll have to say that building with 2×6 studs 24 inches apart is WORSE for the environment, and it is barely practical.
First, it should be noted that most framed elements in a building cannot be framed 24 inches on center (24 inches apart). For the roof, floors and shear walls (i.e. anywhere where plywood is nailed to the framing members) spacing of 16-inch on center is required.
Likewise, if floor joists, for example, are at 16-inch on center, then so should be the studs of the wall that will be “seating” on these joists.
Additionally, other elements in the house are typically made for the 16-inch on center standard (HVAC sheet metal ducts, recessed medicine cabinets, in-wall speakers and so on).
So, when the 16-inch framing is used everywhere it must be, not too much is left for the 24-inch alternative. And that is the “barely practical” part of the equation.
But why am I saying that 2-by-6 studs at 24-inch on center is WORSE for the environment than 2-by-4 studs at 16-inch on center?
While 2-by-4 studs can be “stud grade” or “construction grade” lumber (the lowest quality lumber that is the “left over” from the tree’s outer perimeter), 2-by-6 studs must be “No. 2 or better’” lumber (which is a higher quality lumber from the center of the tree). In other words, everything else being equal, more trees would need to be harvested for the 2-by-6 solution than for the 2-by-4 option — not the most environmentally friendly solution!
My take: Building science is very complex and even those who are steeped in it every day for decades will have differing opinions. This is good to remember when interviewing builders for your own project. Just because they have differing opinions on various issues does not mean that one is right and one is wrong. Likely, both outlooks have validity.