Green Advantages for Advanced Framing Techniques
From the discontinued blog Pardon our Dust from the L.A. Times, two builders share their opinions on advanced framing techniques.
At debate here is whether advanced framing techniques (2x6's 24-inch on center) are justified in their building a more sustainable structure as opposed to using standard framing techniques (2x4's 16-inch on center).
Alan Toker of Megabuilders lays out a very convincing argument that these OVE (Optimum Value Engineering) framing techniques are actually detrimental to the environment and are not practical.
On balance, I'll have to say that building with 2x6 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!
Considering his firm is called "Megabuilders" and they showcase McMansions on their website it's easy to see that pursuing subs who are skilled in OVE techniques cuts into their bottom line. There is also no mention of "green building" or environmentally conscious construction beyond solar panels.
This is not a reflection on the quality of their work as they most likely build solid homes but it's more of a commentary on their philosophy that doesn't jive with the direction of the environmentally sound building process that the Department of Energy is behind.
As Devon Hartman of Hartman Baldwin mentions, "the home you design must be designed with these techniques in mind from the beginning." This mindset must derive from the builder and client and therefore every other home building decision can be based on the initial green-building plan which starts with advanced framing.
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.
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.
To summarize the advantages and disadvantages of advanced framing techniques:
Pros
+ Energy efficient: more room in walls for insulation and less cold spots
+ Less lumber used
+ Faster build time (lower labor cost)
+ Builder saves in lumber purchased, cut and transport time
Cons
- Higher up front cost of design and engineering as well as framing crew training and supervision
- Harder to find builders who skilled in these techniques
- May impact built-in furnishings and other external elements that are set to the standard 16-inch width
