(Author’s Note: The following is part of a new Green Framing chapter I’m adding to my book, “Structural Concepts For the Non-Engineer. I’ll post additional parts in the next few weeks.)
General
Green framing, advanced framing, frugal framing – call it what you will – but in the end it’s all about saving money and resources.
There are lots of ways build-green can be incorporated into a structure: energy efficient appliances and fixtures, special doors and windows, more and better insulation, smart site planning and earthwork to name a few. This chapter is not about those, it’s about stick framing methods – strategies that conserve lumber, concrete, and steel, not to mention the manpower associated with their installation.
A Little Background
Billions of dollars are wasted every year in overbuilt structures. Not only have I been a framer and been guilty of many wasteful practices myself, I see the inefficiency and waste every time I walk a jobsite. Some examples:
- Too-big beams and headers
- Too much blocking
- Too many studs
- Too many trimmers and king studs
- Too many cripples
- Too many holdowns
- Too many shear walls
- Too many posts and piers in crawlspaces
How did we get billion-dollar-wasteful?
Here’s how:
- Building codes have gotten more and more restrictive over the years. They’ve also become so bloated and difficult to use most building industry folks avoid them like the dentist. The result is we’re gun-shy about being efficient. The accepted code mentality is “more is better.” So when we aren’t sure, we throw in more. Tons and tons and tons more. We may as well throw most of that “more” into a landfill; it does no good whatsoever. And in fact, a lot of the time it is counter-productive: more wood, concrete, and steel means less insulation; and more weight adds proportionally to seismic forces. There is no code-incentive for efficiency.
- Most builders have no training in basic structural theory. Its tough to question a more-is-better mentality when you’re not really sure of the underlying concepts. How do builders learn their trade? From other builders; who learned from other builders before them, and so on. Where’s the formal structural training? It’s never been there.
- Most architects and designers don’t receive enough structural training to make them experts. They generally know enough to size a beam or post but to really sharpen the pencil and get efficient puts them out of their comfort zone. And why go there when the building code doesn’t require or encourage it?
- Most engineers are more worried about liability than saving someone else’s money (the owner’s). They have little incentive to produce efficient designs. To an engineer, more is safer. It takes extra time to explore green alternatives, and with engineers especially, time equals money. Why should an engineer cost himself more money, incur more liability, and go against the grain of the code, especially when he can snow job the owner as to how massively strong he’s made the building? Owners don’t know to ask the right questions, and the engineer grins all the way to the cruise ship.
- Building officials have zero incentive to enforce or even encourage green techniques. They answer to the building code (see first bullet point.)
- Private industry has no incentive to do anything either. Would you expect lumber companies, framing hardware companies, or concrete companies to stand up and start shouting for less use of their products? What has happened, however, is that new, efficient mousetraps in the form of SIPs (Structural Insulated Panels) and ICFs (Insulated Concrete Forms) have sprung up. Those are terrific products and I endorse them heartily. But they do nothing for the vast majority of builders who use traditional methods and materials.
It’s a racket and vicious cycle that desperately needs fixing. The first step is education. Once builders, designers, architects, and code officials understand what’s going on and that the solutions are attainable by them, they will start putting pressure on the engineers. Or, better yet, they’ll start implementing the designs themselves.
In the BC days (Before Computers) it was unreasonable to expect non-engineers to perform structural calculations. But with the advent of computers and user-friendly software, now anyone can do basic structural design.
Throughout this chapter we’ll use my company’s software, ConstructionCalc, for our green designs. If you’re new to structural design aids (span tables or software) you’ll probably want to bone up at http://www.constructioncalc.com, checking out the free examples and white papers.
To keep things popping along, I’ll assume you know the basics. Again, if you need a little background please avail yourself of the freebies at http://www.constructioncalc.com.
(to be continued)
Copyright, August, 2009, Tim K. Garrison, P.E. All rights reserved.