Steel-Frame House Construction eBook (PDF)

Contents

1 What Is Light Gauge Steel? 5

Why Switch from Dimensional Lumber? 5

The Growing Interest in Steel, 7

The Transition from Wood to Steel, 9

2 Design and Standardization, 13

Hiring an Engineer, 13

Prescriptive Method, 14

Steel Fire and Sound Ratings, 18

3 Designing the Steel-Framed House, 21

Sizing the Steel Members, 24

Planning for Plumbing, Electrical & HVAC, 27

Steel Framing Design, 27

4 Light Gauge Steel, 29

Production of Molten Steel, 29

Purchasing from Manufacturers and Distributors, 31

5 Steel Framing Tools, 33

Fastening Tools, 33

Cutting Steel, 37

Clamps, 39

Bending Steel, 39

Miscellaneous Tools, 40

6 Steel Framing Fasteners, 43

Screw Basics, 43

Point Types, 45

Framing, Sheathing and Gypboard Screws, 46

Drive Pins and Nails, 47

Welding and Clinching, 49

Anchors, 49

7 Types of Construction, 51

Stick Framing, 51

Panelization, 52

Pre-Engineered Buildings, 54

Cost Impact, 54

8 Before Construction Begins, 55

How Will You Cut the Steel?, 55

Simplification, 55

Your Cut List, 55

Estimating Costs, 59

Material Delivery, 60

9 Foundations and Anchoring, 61

Concrete Tolerances, 61

Slabs-on-Grade, 61

Crawl-Space Foundations, 61

Basement Foundations, 61

Anchorage, 62

10 Floor Joists — First Floor, 67

Girders and Bearing Walls, 67

Layout, 70

Floor Squeaks, Pongs and Vibrations, 77

11 Wall Construction — Loadbearing Walls, 79

Wall Assembly, 79

Installing Studs, 81

Bracing, 85

Wall Erection, 89

12 Second Floor Construction, 93

Bearing Walls or Clear Spans, 93

Setting Floor Joists, 93

Safety, 95

13 Roof Framing with Rafters, 97

Designing the Rafter Roof, 97

Material Take-Off and Cut List, 101

Framing the Rafter Roof, 104

Finishing the Rafter Roof, 109

14 Roof Framing with Trusses, 111

Manufactured (Pre-engineered) Trusses, 111

Site-Built Trusses, 111

Ridge Caps, 125

Bracing, 125

15 Roof Completion Details, 127

Rafter Heels, 127

Roof Hold-Downs, 127

Roof Fascia, 128

Collector Blocks, 129

Rakes, 131

Barge Rafters, 131

Soffits, 131

16 Specialty Framing, 135

Curved Walls, 135

Curved Floors, 137

Archways, 137

Dormers, 137

Stairways, 138

17 Thermal Considerations, 139

Meeting the Energy Code, 139

Cavity Insulation, 140

Foam Insulation, 142

Loose Cellulose, 145

18 Wall Construction — Nonbearing Walls, 147

Layout, 147

Nonbearing Wall Studs, 147

Wall Assembly, 148

In-Place Wall Framing, 148

Gypboard Installation, 151

Attaching Molding, Cabinets and Shelving, 151

19 Exterior Finishes, 153

Factors to Consider, 153

Attaching the Exterior Finish, 154

20 Working with Utility Subcontractors, 159

Planning for Utility Runs, 159

Working with Plumbers, 160

Working with Electricians, 162

Working with HVAC Contractors, 164

21 Inspections, 165

Inspection Checklist, 166

22 Selling to the Homebuyer, 175

Marketing Tools, 175

Destroying the Myths, 176

Conclusion, 177

Prescriptive Method for Residential Cold-Formed Steel Framing, 181

How to Use the Steel-Frame Download, 289

List of Steel-Framing Details, 312

Index, 313

Chapter One

What is Light Gauge Steel?

Light gauge steel framing members (sometimes called cold-formed steel) are made from structural-quality sheet steel that’s formed into shapes either through press-braking blanks sheared from sheets or coils, or more commonly, by roll-forming the steel through a series of dies. Unlike hot-formed structural I-beams, neither process requires heat to form the shape, thus the name “cold-formed” steel. Light gauge steel products are usually thinner, faster to produce, and cost less than their hot-formed counter-parts. Figure 1-1 shows a typical steel-framed house under construction.

Why Switch from Dimensional Lumber?

Why are we looking for alternatives to dimensional lumber? Let’s start out with a little history.

The United States has enjoyed an abundant supply of timber products over the past two centuries. The availability and workability of wood has enabled builders to construct millions of homes in North America. Today, new residential construction and remodeling consumes two-thirds of the lumber used. Any change in the supply and cost of lumber directly impacts the homebuilding market.

This impact was strongly felt in 1993, when lumber prices more than doubled. Framing lumber composite prices jumped from $200 per 1,000 board feet in 1990 to $500 in 1993. You can see this unusual leap in prices shown in the graph in Figure 1-2. The rising price sent a panic throughout the residential construction industry. While homebuilders lobbied for lower lumber prices, they also looked for alternatives to lumber.

There’s a lot of speculation as to why prices jumped so drastically. Some environmentalists were concerned that too many old growth forests had been cleared. Concerned about wildlife habitats, they lobbied to protect endangered species, such as the spotted owl, and require the selective cutting of timber.

The wood industry looked toward imports from Canada to satisfy construction needs. They assured builders that the supply would meet demand, especially through a combination of imports and managed forests. They described timber products as a “sustainable” industry, with new growth satisfying demand. However, over the past decade overall lumber prices have both increased and become more volatile.

In 1991, lumber costs for a 2,000 square foot home averaged about $5,000. In 1993, the lumber cost for the same size home was about $12,200 (up to $491 per 1,000 board feet). Though lumber prices dipped back down a bit in 1995 and 1996, it’s become apparent that the framing costs of construction are now taking up a larger part of the total cost of building a home. In January 2000, the framing lumber composite price was $387 per 1,000 board feet, compared with $231 in January 1990. Today, framing costs are almost consuming 20 percent of the total cost of the home. Figure 1-3 shows the relationship between the rise in the cost of lumber per 1,000 board feet and framing as an increasing cost of the overall lumber expense for the average 2,000 square foot home.

Figure 1-3
Cost of lumber for a 2,000 square foot home

We all know that the bottom line for homebuilders is always cost, profit, and staying in business. No matter how many advantages steel may have over wood, framers won’t begin using the product until it can compete in the market. In 1993, for the first time, the price of a steel framing package started to become competitive with the wood package for the same components of the home. That’s when builders began thinking about switching from wood to steel framing.

In that year, the National Association of Home Builders (NAHB) Research Center initiated an alternative materials program in response to increasing lumber prices and a perceived decrease in lumber quality. Light gauge steel framing was considered as one possible solution. The NAHB Research Center generated a report called “Alternative Framing Materials in Residential Construction: Three Case Studies.” It identified light gauge steel as a cost-competitive solution in 1994, especially in wall framing. This was the first time in a long while that the home building industry was able to find an immediate solution to a problem with a product.

The NAHB Research Center Tool Base Hotline has handled thousands of calls over the last few years from builders seeking information on steel framing. Total shipments of light gauge steel framing used in residential construction grew in 1998 by 44 percent to 140,000 tons, up from 97,000 tons in 1997. The biggest gains in market share were in non-loadbearing studs and floor joists.

The North American Steel Framing Alliance (NASFA) was formed as an affiliate of the American Iron and Steel Institute in 1998. NASFA’s mission is to enable and encourage the widespread, practical and economic use of and preference for light gauge steel framing in residential construction. In order to achieve its mission, NASFA has identified several strategies to help accelerate the use of steel framing. One of them is to reduce the cost of construction.

NASFA also plans to develop the infrastructure necessary to support local builders. By building local alliances, finding less expensive construction details, and providing training opportunities, it’s working to achieve its goals.

For more information for contractors and the consumer, NASFA maintains a hotline to field calls. You can reach them at 1-800-79-STEEL, or visit their Web site at www.steelframingalliance.com.

Advantages of Steel Framing

A steel-framed home is a high-quality home. By virtue of its material characteristics and properties, steel offers significant advantages to both home-builders and consumers. Steel studs and joists are strong, lightweight, and made from uniform-quality material. Steel walls are straight, with square corners, and all but eliminate pops in drywall. This virtually does away with the need for costly callbacks and adjustments.

Consumers enjoy steel framing for fire safety and termite protection. Steel framing doesn’t contribute combustible material to feed a fire. In Hawaii in 1998, over one-third of all new homes were built with steel to protect against the voracious Formosan termite. These termites, as well as some other harmful parasites, can destroy a house there in one year.

Steel-framed houses can be designed to withstand wind and seismic loads caused by hurricanes and earthquakes. The strength and ductility of steel allows it to meet the strongest wind and seismic ratings in the national building codes. And steel joists and trusses can achieve greater spans, opening up large spaces inside a home.

One extra advantage: steel is also recyclable. Most steel manufactured today contains an average of 25 percent recycled content. Steel takes the pressure off of renewable resources and saves valuable landfill space.

...And Some Disadvantages

With all of these advantages, why don’t we see more steel houses being built? Several barriers still inhibit the growth of this alternative construction material. Most of the barriers impact the cost of the home. While steel framing material costs are now competitive with lumber, the labor and engineering costs tend to be higher. Several factors impact higher labor costs. There is a lack of skilled framing labor in steel framing. This makes it difficult to find competitive steel carpenters. There is an inherent higher connection cost using screws and screw guns versus nails and nail guns. It just takes longer to apply a screw than a nail. There is also, in colder climates, an added cost for applying a thermal break. Because there are no standards in the energy codes, steel suffers a penalty in the extra insulation costs.

In addition to cost problems, there is a lack of infrastructure to support the construction of a steel-framed home. Consider code approval, design, material suppliers, and framers. There are a lot of people working in these fields who don’t know how to inspect, design, sell and work with steel studs, rafters and joists. Prescriptive design tables are only now being introduced in the building codes.

Finally, consumers aren’t aware of all the benefits steel has to offer. When it comes to amenities, most homebuyers select a family room, spa or a three-car garage. What is hidden in the walls doesn’t have a perceived value until there’s a fire, termite damage, nail pops or crooked walls.

The Growing Interest in Steel Among Framers and Consumers

Despite these disadvantages, there has been a growing interest in steel among framers and consumers. As a result, in 1994 and 1995 the American Iron and Steel Institute teamed up with the NAHB Research Center to conduct introductory seminars on residential steel framing. The seminars, called “Learn to Frame with Steel,” were conducted in over 70 cities across the country and have reached more than 2,000 home builders, design professionals, and code officials.

In 1996, in response to builder demand for “hands-on” training, the Institute expanded their program into a week-long training seminar. The last day of the seminar used the completed steel frame house shown in Figure 1-4 as a classroom to show how to work with steel, from concept to finishing. In 1998, the Institute published the National Training Curriculum for Residential Cold-Formed Steel Framing, which was written around the 1996 program. This Curriculum is available to training centers both in the form of a three-ring binder and on CD-ROM. Call NASFA at (202) 785-2022, or check their Web site at www.steelframingalliance.com.

Regional Training Centers

Over the past few years, regional training centers have been established to bring framers up to speed quickly. I’ve had the opportunity to work with students in several of these training programs. There always seems to be a similar mix of people, including experienced carpenters, home builders, architects, engineers, retired code officials, instructors, and foreign nationals.

Though everyone seems to be looking for something different to take home with them, most want to start framing with steel, or start up a company of their own. They may not be able to learn how to do everything in a one-week training program, but they do leave behind their fear of the unknown. The programs give them the confidence they need to go out and frame with steel on their own.

Here are the locations of some of these training centers:

Orange Coast College — College courses in steel framing
Costa Mesa, California
714-432-5582

Ivy Tech Training Center — Steel framing training sessions
Gary, Indiana
219-981-4402

USS-POSCO Training Facility — Two-week introductory course
Pittsburg, California
925-439-6241

As steel framing gains in popularity, more training centers are being developed. Hundreds of steel framing curriculums have been distributed across the country. Check the NASFA Web site for the latest information.

The Transition from Wood to Steel

One of the reasons framers can switch to light gauge steel without a major transition is that a steel house is framed much like a wood-framed house. You’re still using 16- or 24-inch spacing for studs and floor joists; you can make up headers from steel members and fasten materials like plywood and Oriented Strand Board (OSB) to the steel framing in much the same way as wood. Basically, stick-for-stick, you can replace each of the wood framing members with steel. But new, innovative details for steel are being developed everyday. The L-header, for instance, is a new, cost-effective method to frame headers with steel.

Hybrid Framing

Another point that makes the transition to steel easier is the fact that you don’t have to convert to framing completely with steel all at once. Many builders take a step-by-step approach to steel framing, switching over one part of the house at a time. This is sometimes referred to as “hybrid” framing. Some use steel for only the interior nonbearing walls, as shown in Figure 1-5. This way, they avoid today’s steel engineering costs while paying less money for the steel studs. Others frame their floors with steel joists and frame the exterior loadbearing walls with wood. You may even choose to frame everything below the top plate with steel, and have your trusses delivered by the same wood truss manufacturer you use now. Or of course you can choose to have your homes 100 percent framed out of steel and use steel trusses or rafters.

Considerations with Steel Framing

If you’re considering framing with steel, you’ll have to do your homework and analyze the costs. You’ll need to review the advantages described earlier and weigh them against the barriers.

Once you take a look at the pros and cons and apply them to your projects and model homes, it will become apparent what part of your homes you can frame with steel, practically and economically.

The purpose of this book is to familiarize you with the basic uses of steel framing in residential construction. As NASFA, the NAHB Research Center, HUD and others strive to reduce and eliminate the existing barriers to steel-framed construction, new products, tools and services will be introduced. Keep up-to-date by frequently checking NASFA’s Web site or the ToolBase services at www.NAHBRC.org.

Workforce

One of the problems you may encounter if you’re new to residential steel framing is finding carpenters and framers that have experience working with gauge steel. In many parts of the country, especially away from the major urban areas, there simply aren’t enough framers trained in steel to support this type of construction.

You’ll need to either bring experienced workers in, or train your own crew. Many builders who switched over to steel didn’t start with trained crews and lost a lot of money building their first few houses. Some didn’t survive their first efforts. Remember, steel is a relatively new material, and it’ll take longer to complete the jobs the first few times you work with it. Look into either getting a trained labor force, or professional training for your own people (Figure 1-6). The cost of investing in proper training will be offset by the manhours you’ll save on your first few jobs. How long will it take you to try to figure out what to do with that soffit detail or how to tackle the outriggers without some outside help?

There are three main sources of framing labor available for training in steel:

• Experienced wood carpenters

• Commercial drywallers

• Unskilled laborers

Experienced Wood Carpenters — Experienced carpenters are excellent candidates for training in light gauge steel framing. They’re already familiar with wood framing and understand 16- and 24-inch modules. They can take a floor plan and elevation and turn simple layouts into a well-constructed house. Master carpenters do this all the time with wood, without a single detail or section on how to complete a difficult roof hip and valley section, or how to cut in stairs. However, very few carpenters have worked with light gauge steel or even used a chop saw or electric shear. There’s a learning curve to this, and not all carpenters are willing to make the change.

However, in the training seminars I’ve instructed, the students who catch on the fastest are the carpenters. They always stand out in the group because they’re the first to understand layout, first to walk top plate, and the first to stack trusses. They already know how to frame a house, so your primary task is simply to help them make the conversion to steel.

Drywallers — Commercial drywallers, on the other hand, are used to framing interior walls out of steel. They’re also very comfortable using a screwgun, which is one of the main tools you use in steel framing. They know how to work with a chop saw and they’re comfortable coping and cutting steel. But not very many drywallers have framed an entire house. And even fewer have stayed up all night trying to figure out a difficult roof valley or how to calculate the ridge height on a conventional roof. You can see, looking at the hip detail in Figure 1-7, that these are not easy tasks to pick up. Training for commercial drywallers is heavy on the fundamentals of framing and layout.

Unskilled Labor — Some builders prefer to start from scratch with unskilled laborers who don’t have preconceived notions about either wood or steel. The unskilled worker has nothing to compare with. Then again, like the drywaller, an unskilled laborer doesn’t have the experience the carpenter has in the art of home building. An unskilled laborer needs to learn not only the basic skills necessary to frame a home, but also the specifics of how to work with steel.

Size of Framing Crews

You can use the same size framing crew for steel as for wood framing. A typical steel framing crew consists of two or three experienced framers and one or two apprentices. If most of your steel is cut to length, you won’t need to dedicate one man to cutting steel on a chop saw or shears. I’ve known some steel framers who even work by themselves on a project, and stick-frame their wall in place.

As with any type of framing, if you have too many men, they’ll get in each other’s way; too few and you won’t make the schedule. You’re the one who has to ultimately decide how many men should be on your crew. One of the factors in deciding how large a crew you need is how long and heavy your walls are. There’s more about this later.

Safety

Safety is an important part of any project. Common sense alone isn’t enough to keep a job site safe. The Model Safety & Health Program put out by the National Association of Home Builders in Washington, DC is a great reference for job sitesafety and has many good suggestions for keeping your job site accident free. Here are some of the safety tips that you have to add to your list when framing with steel. These tips don’t cover all situations but they will be especially helpful if you’re framing with steel for the first time.

Wear work gloves whenever possible. The gloves should be thick enough to protect your hands from cuts, but thin enough so you can easily finger the screws. Gloves will also protect your hands from hot steel in the summer and cold steel in the winter.

Watch out for sharp edges! Just as you can easily pick up a sliver from a wood 2 X 4, you can cut your hand on a metal stud. Gloves help, but common sense and caution help prevent need-less injuries.

Always wear ear protection when cutting steel with a chop saw. Chop saws are loud!

Always wear safety goggles when cutting steel or fastening steel overhead. The chop saw will send debris flying that could damage your eyes. There’s also a good chance that some hot steel chips could fall in your eyes when you’re screwing members together overhead. Safety goggles are a good idea whenever anything could fall into your eyes.

If you use carbide-tipped blades to cut steel in circular saws, wear a face shield and long-sleeved shirts. The metal chips that fly out of the saw can damage your eyes and skin.

Be careful not to damage electrical cords by dropping steel members on them. The sharp edges on the steel can easily cut through the plastic coating and produce an electrical hazard.

Be especially careful when the steel is wet. Steel can be very slippery.

Familiarizing yourself with the advantages and current problems with working with cold-formed steel, as well as safety issues in the workforce, will help you make intelligent decisions in preparation for your first steel framing project. The next several chapters focus on other important issues you should consider before you frame that first house. I’ll start with design considerations and move through tools, fasteners, and ordering steel. Once we have these basics under our tool belt, we’ll tackle the actual framing of the house.

Steel-Frame House Construction
by Tim Waite

As lumber prices rollercoaster, and quality declines, light-gauge steel framing has become a cost-effective alternative for building homes in North America. But making the switch from wood to steel can be a mystery for a wood-frame builder or framer. Lack of a skilled work force is one of the biggest barriers keeping steel framing from taking a more significant market share. Until recently, only a few framers knew how to properly frame out of steel.

This book takes a major step toward changing that. it provides the basic methods in an easy-to-follow, hands-on format to quickly bring the home builder or framer up to speed on steel framing. If you're a prospective steel framer, you'll find the clear instructions here will shorten your learning curve significantly, and save you time and money. The book covers not just how to frame the house, but everything you need to know before you even pick up a screwgun:

Included in the book is the text of the NAHB Research Center's Prescriptive Method for Resiclential Cold-Formed Steel Framing - the basis for most Code requirements for steel construction. It shows exactly how residential steel must be framed, and gives the span tables, load requirements and fastening schedules you need to erect Code-approved framing.

Included with this eBook is a FREE Web download for the National Estimator, an easy-to-use estimating program with 35 pages of manhour estimates, and material and labor costs for residential steel-frame construction.

Tim Waite, a licensed professional engineer, has worked as a field engineer for the past 20 years. He was introduced to the light-gauge steel framing industry in 1992, and tooled up side-by-side with steel framers nationwide to find the most cost-effective details for residential steel framing. With the NAHB Research Center, he conducted classroom and hands-on training seminars for builders across the country and overseas. Subsequently, Tim wrote the National Training Curriculum for Residential Cold-Formed Steel Framing for the American Iron and Steel Institute. He serves on several committees for standardizing steel framing details and methods. In 1997 he started the Hawaii Steel Alliance, Inc., an association developed to further educate the industry and promote the use of steel framing. He currently works for the Simpson Strong-Tie Company.