Building codes are a relatively new invention. The first widely-accepted building code in the U.S. was written in the early 1900s. Today’s building code, the International Building Code (IBC), has its roots in the Uniform Building Code (UBC) which was first published in 1927. Over the years many local jurisdictions adopted building codes but many did not. Even today there are jurisdictions in the U.S. that do not issue building permits nor require adherence to any building code.

Where I live in western Washington, building codes are strictly enforced for any structure from a shed to a fence to a sky scraper. Around here it’s unthinkable that a house might be designed by a non-professional and built without a building permit.

But where my brother lives in Kansas, there are no such requirements. Draw up your plans on a napkin, grab your hammer and go. There are lots of places like that in our country today.

So in America we’ve got quite a mix-mash of structures. A few that meet current codes but many, many that don’t.

I took some photographs the other day of old buildings in my county.

The first one, I call the Titanic. This house is probably at least 50-years-old and as you can see has settled terribly. The house is likely built partially over an old slough that was filled with logs and other debris. The part built over the slough embankments has not settled but the part built over the fill-debris has. This is called differential settlement. Incredibly, people still live in this house.

The next structure is a 75+ year-old commercial building. By today’s standards it contains not a single shear wall nor a horizontal diaphragm. It is listing about a foot out of plumb, yet there it stands.

Here is a very large barn, probably 50+ years old. Note how huge its wind sail area (roof) is. Also you can see that it is located in the middle of an open valley with no trees or other buildings to shield it from the wind. The gable end walls are mostly door openings, and the wood panels in between don’t come close to any sort of legal shear wall. The roof isn’t a legitimate diaphragm. There’s a two-foot sag in the roof at the eaves. Yet year after year, winter after winter, storm after storm, this barn continues to serve.

According to its historic placard, this building was constructed in 1890. It has undergone an extensive tenant improvement, but other than new windows and doors, the exterior walls, floor and roof framing are original. It is built partially over a salt water channel, supported on timber piers. The horizontal siding on the long walls shows settlement up to a foot in several areas. The above photo is the rear wall. Note all the windows and doors (read: no shear panels.)

The front wall is pretty much the same: all windows; which count for nothing in resisting lateral (wind and earthquake) loads. Here is what this wall looks like from the inside:

This is also the front wall, about mid-height.

This wall is constructed of horizontal siding attached to 2×4 studs. Not one shear panel, holdown, or hurricane clip.

Roof framing is 2×6 rafters, originally spanning 20+ feet. There is no ridge beam. I’d go so far as saying there isn’t one code-compliant piece of lumber or connection in this entire building. And in fact most structural elements are overstressed, according to current code, by several hundred percent.

In its 119-year life, why hasn’t this building imploded or blown over?

This last building was also built in 1890. One corner (the one by the streetlight) has settled at least six-inches. But that’s not what makes this one of the most dangerous buildings in the county. The front wall is all glass. No shear walls, no portal frames, no buttress walls, nothing. And the next parallel interior wall is some 30-feet back into the building. As the one corner sinks, the building tilts causing racking (shear) stress on the window wall. Should a window break or crack there is a real possibility that this building would fall over sideways – I’ve seen it happen to a building of similar construction in a nearby town. Yet, this building stands.

All of the aforementioned structures have lived through snow accumulation of several feet, howling wind storms, and earthquakes.

All across America and the world are buildings that don’t come close to meeting current code. It usually takes a hurricane, tornado, severe neglect, freakish snow storm, or 7+ magnitude earthquake to bring them down. And even then many survive.

So what’s the point?

The point is that things not built to code are usually plenty strong and those that are built to code are vastly stronger than they need to be in most cases.

If you live in a jurisdiction that has building codes and enforces them, you don’t have a choice but to comply with those codes. But you don’t need to overbuild.

Let me say that again. Our building codes contain so much factor of safety, no one should ever feel compelled to exceed them. The grossly non-code-compliant buildings on the previous pages, in my opinion, provides stout testimonial.

Our industry should be actively searching for ways to trim our designs so that they just comply with code and no more. If we build stronger than code we’re literally throwing away money and effort. And we’re not building green.

This book is about minimal, yet code-compliant, structural design. Green design. The trick is understanding the underlying structural concepts: where loads come from; where they go; and how they’re resisted. With that knowledge, we can maximize efficiency and save money.

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 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 www.constructioncalc.com.

(to be continued)

Copyright, August, 2009, Tim K. Garrison, P.E. All rights reserved.