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Builders' SteelStud Guide
Publication RG-9607October 1996
1726 M Street, NW, Suite 601Washington, DC 20036-4523
1-800-79-STEEL
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Copyright 1996 by the American Iron and Steel Institute
BUILDERS' STEEL STUD GUIDE
July 1996
Prepared for:
American Iron and Steel Institute1101 17th Street, NW
Suite 1300Washington, DC 20036-4700
Prepared by:
NAHB Research Center, Inc.400 Prince George's Blvd.
Upper Marlboro, MD 20774-8731
Copyright 1996
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The NAHB Research Center developed this publication for the American Iron and SteelInstitute with guidance from the AISI Residential Advisory Group. It is intended to providecontractors with instructions and details for constructing homes with cold-formed steelstuds. AISI believes that the information contained in this publication substantiallyrepresents industry practice and related scientific and technical information, but theinformation is not intended to represent an official position of AISI or to restrict or excludeany other construction or design techniques.
American Iron and Steel Institute
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The following publication has been developed by the American Iron and Steel Institute(AISI) which is comprised of representatives of steel producers in the US, Canada andMexico. The NAHB Research Center has exercised due diligence in consulting a widerange of pertinent authorities and experiences and has used its best efforts to presentaccurate, reliable and useful information. AISI acknowledges the principal author of thispublication, Chad J. Garner, reviewers Mark Nowak and Timothy J. Waite, P.E., andadministrative assistance by Kimberly Koontz and Julie Kostro. AISI also acknowledges allthe individuals of the Residential Advisory Group who contributed to this effort.
The materials set forth herein are for general information only. They are not a substitute forcompetent professional assistance. Application of this information to specific project orsetting should be reviewed by a qualified individual. In some or all jurisdictions, suchreview is required. Anyone making use of the information set forth herein does so at his orher own risk and assumes any resulting liability.
Builders’ Stud GuideOctober 1996
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ACKNOWLEDGEMENTS
We wish to recognize the American Iron and Steel Institute (AISI) for funding this guide andfor their efforts towards developing the residential steel framing industry. AISI has over 40company members who provide the sheet steel necessary for residential steel framing.
The preparation of this guide required the talents of many dedicated professionals. Theprincipal author of this publication was Chad J. Garner, with review by Mark Nowak andTimothy J. Waite, P.E., of the NAHB Research Center, and administrative assistance byKimberly Koontz and Julie Kostro. Special thanks also go to Mike Meyers (USX), RichardHaws (AISI), Mark Mengel (Crown Building Systems), and Kevin Gramley (UnimastIncorporated) for their input.
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CONTENTS
INTRODUCTION.......................................................................................................................1Advantages of Steel Framing........................................................................................1Measures Unique to Steel .............................................................................................1Getting Started with Steel Framing ...............................................................................2Description of Members.................................................................................................3Purchasing Steel Framing Material...............................................................................4
TOOLS AND FASTENERS ......................................................................................................5Field Cuts.......................................................................................................................6Screw Guns....................................................................................................................7Fasteners .......................................................................................................................9
INTERIOR NONLOADBEARING-WALL CONSTRUCTION.................................................11Typical Wall Assembly ................................................................................................13Corner Framing............................................................................................................14Framing at Openings...................................................................................................14
LOADBEARING-WALL CONSTRUCTION............................................................................15Design Considerations ................................................................................................17Layout...........................................................................................................................17Typical Loadbearing-Wall Assembly ..........................................................................18Framing a Wall Opening .............................................................................................18Corner Framing............................................................................................................19Raising the Walls and Temporary Bracing.................................................................21Attaching Loadbearing Walls to the Foundation or Floor Deck.................................22Shear Bracing ..............................................................................................................24
ATTACHING FINISH MATERIALS.........................................................................................24Baseboard and Other Interior Trim .............................................................................24Cabinets and Vanities..................................................................................................24Closet Shelving............................................................................................................25Gypsumboard Installation............................................................................................25
UTILITY INSTALLATION........................................................................................................26Field Cuts.....................................................................................................................26Plumbing ......................................................................................................................27Electrical.......................................................................................................................28Duct Work ....................................................................................................................29Insulation......................................................................................................................30
APPENDIX - Sample Floor Plan/Cut List .............................................................................A-1
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INTRODUCTION
Steel has helped shape the world we live in for hundreds of years. Bridges, railroads,automobiles, and even our homes all contain some steel. More recently, builders are usingmore cold-formed steel in homebuilding to frame floors, walls, and roofs. Despite the recentincrease in interest, cold-formed steel framing is not new. It is a field-proven material inboth the commercial and residential construction industries.
Resources for the production of cold-formed steel are plentiful. The technology hasimproved so that the price of steel has remained relatively steady. This is in contrast to thewide fluctuations that have occurred with lumber prices since the early 1990s. Steel canalso be consistently produced to very specific strengths, shapes, and sizes within smalltolerances. These and other factors have rendered steel a viable framing material to meetthe demands of the residential construction industry.
Advantages of Steel Framing
In addition to its cost effectiveness and consistent quality, steel has many more advantageswhich make it appealing to builders and homebuyers.
• Cold-formed steel is a proven framing material with a long track record in thecommercial building industry.
• Steel can be used to frame a house in different ways, including stick-built, panelized,and pre-engineered buildings. Steel homes can be built using layouts similar towood framing.
• Steel's inherent strength can provide the builder with design flexibility. Steel-framedhomes may also be built to meet the highest seismic and wind load specifications inthe country.
• Steel is non-combustible, insect resistant, and will not rot.• Steel will not shrink, split, or warp, resulting in fewer call-backs for nail pops and
busted seams in gypsumboard.• Steel framing members are light and easy to handle, reducing worker fatigue.• Waste from steel framing is recyclable.• Pre-punched framing members facilitate the installation of electrical wires and other
utilities.
Measures Unique to Steel
Like any framing material, steel has some unique characteristics that require the builder todo things a little differently. This may slow a builder down at first; however, most buildersquickly overcome these differences.
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• The top and bottom tracks of steel walls are usually not capable of transferringvertical loads. This will require you to use an "in-line" framing technique. It requiresslightly more planning and more precise workmanship.
• The tools and fasteners, although not unfamiliar, take some practice to becomeefficient in their operation.
• Subcontractors that are unfamiliar with steel will need to be trained.The thermal properties of a steel wall may require the application of some differentinsulating practices, especially in northern states. For the suggested insulationlevels in your area of the country refer to AISI's Thermal Design Guide for ExteriorWalls, publication #RG-9405.
• Gloves are recommended when working with steel to protect hands from sharpedges.
Getting Started with Steel Framing
Making the transition to steel framing can be a gradual process or a complete changeover. Many builders start with interior partition walls because they are generally accepted in mostbuilding codes and do not require a special design. This gives the builder and theirsubcontractors an opportunity to become comfortable working with the product prior toexpanding into loadbearing members.
Regardless of which approach you take, there are a few basics that apply to bothloadbearing and partition studs. These are covered in the following sections followed byspecific guidelines for each type of wall. Recommendations for gypsumboard installers,trim-out carpenters, electricians, plumbers, and insulators are provided in the last sections.
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Description of Members
When selecting steel for framing, three primary variables should be considered: shape,thickness, and strength of the steel. Although many shapes of cold-formed steel areavailable, the most common in residential construction are the "C"-shape and the track. The "C" is used as a header and a stud, whereas the track is used like the top and bottomplates in wood construction (except most track is not capable of transferring vertical loads).
The track section has a web and aflange, but does not have the lip that ispresent on the "C"-shape. This allowsthe "C" to fit into the track. Thus, theweb of the track section is measuredfrom the inside of the flanges (seeFigure 2). The flange of the trackshould be at least 1¼ inches to providea surface for attaching gypsumboard,sheathing, and trim.
The "C"-shape consists of three parts:the web, flange, and lip (see Figure 1). Care must be taken when selectingstuds to ensure the dimensions arecompatible with doors, windows, andother parts of the home. A 3½-inch or5½-inch web (measured from theoutside of the flanges) is consistentwith today's lumber dimensions,although other sizes may be used butrequire additional attention at doorsand windows. The flanges range from1½ inches to 1_ inches depending onthe manufacturer and the type of stud.
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Other members that may be required for steel framing include flat straps and angles. Straps, which come in a variety of widths, are typically used for wall bracing and bridging.Angles are usually used for bulkheads and other specialty framing where a "C"-shape studwill not work.
Cold-formed steel members come in a variety of thicknesses as shown in Table 1. Morerecently, the industry is beginning to adopt designations in mil thicknesses (inches x 1000)as shown in the first column of Table 1. The term "gauge" in the second column has beenthe traditional means to identify steel thickness.
Table 1. Nominal Thickness of Steel
Minimum DeliveredThickness (mils)
Reference Gauge Number
18 25
27 22
33 20
43 18
54 16
68 14
97 12
In addition to its thickness, the strength of a steel section is dependent on the size, shape,and yield strength of the steel. In the United States, most steel is designated as 33 ksi (kipsper square inch) for 18- to 43-mil steel and 50 ksi for 54 mil and thicker.
Purchasing Steel Framing Material
Sheet metal is produced in steel mills. The sheet steel is cold-formed by othermanufacturers�commonly called roll-formers�into the shapes used for framing. Nonloadbearing framing material can be purchased through distribution outlets such ashome centers, building supply centers, or directly from the roll-formers. Loadbearingframing materials are also supplied through roll-formers and through local or regionaldistributors. AISI publishes a Residential Products Directory to help locate thesecompanies. Not every builder is located close to a roll-former or distributor, so the first stepshould be to locate a supplier or roll-former that operates in your area.
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TOOLS AND FASTENERS
Cutting and fastening steel requires different tools than does lumber and other materials. Inorder to reduce frustrations on the jobsite, you should become familiar with these tools andlearn the correct application for each. A quick reference for tools and fasteners is shownbelow in Table 2.
Table 2. Tools Recommended for Use with Steel Framing
Cutting
� Aviation snips - cuts up to 33-mil material and makes cuts for coping track flanges.
� 14-gauge swivel head electric shear - cuts up to 68-mil material.
� 14-inch chop saw - for cutting multiple sections simultaneously, especially partition studs.
� Step drill bit, 1 inch - for drilling holes in studs and track.
� Hole punch, 1¼ inch - for field punching holes for the installation of electrical and plumbing systems.
Fastening
� Adjustable clutch screwgun - with industrial motor (5.4 amps), 0-2500 rpm variable speed, reversible,bit
tip holder release, adjustable torque control for framing.
� Magnetic bit tip holder and #2 Phillips bit tips.
� 5/16-inch magnetic hex driver for hex-head screws.
� Two pair of 3-inch, two pair of 6-inch, and one pair of 12-inch locking C-clamps with regular tips forclamping steel together while fastening.
� Deep-throat bar clamp - for clamping headers in wall sections while fastening.
Gypsumboard screwgun - with industrial motor (5.4 amps), 0-4000 rpm variable speed, reversible, withdepth locating nose piece for sheathing and gypsumboard installation.
Miscellaneous
� 3½-inch and 5-inch hand seamers - for bending and coping track.
� Bull-nose pliers - for removing screws.
� Felt markers - for layout and cuts (black and red).
� Other miscellaneous tools include: tape measure, speed square, utility knife, wallboard ax, and 50'grounded extension cords.
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Field Cuts
As with any material, it is best to minimize the need for field cuts. Many roll-formingmanufacturers will do most of the cutting during production if provided with a detailed cutlist. This can significantly shorten on-site construction time. A sample cut list is provided inthe Appendix. Pre-cut material has an added advantage because suppliers use a shear cutwhich folds the galvanized coating over the ends and prevents corrosion.
Where cutting is required, a felt markerworks better on steel than a pencil. Forcutting 18- and 27-mil steel, aviation snips(see Photo 1) will suffice. Thicker steel willrequire a chop saw with an abrasive blade(see Photo 2). Electric shears (see Photo1) are also available in models that can cutup to 68-mil steel. The shears will producea cut similar to a manufacturer's cut wherethe galvanized coating is folded over theedge of the cut. An abrasive cut will burnthe galvanized coating, leaving the cutunprotected from corrosion. Thegalvanized coating, however, will not allowcorrosion to spread beyond the cut.
Studs typically have pre-punched holesevery 24 inches to allow for theinstallation of utilities. Sometimes pre-punched holes are not sufficient andfield cuts will be needed. Manual studpunches are available and make a 1¼-inch hole. For larger holes a hole sawor step bit is used (see Photo 3). Additional information on field-punchedholes is contained in the section onUtility Installation.
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Screw Guns
When fastening steel framing memberstogether you will need an industrial-quality (5.4 amps), variable-speed up to2500 rpm, reversible screwgun to drivethe self-drilling fasteners (see Photo 4). A 4000-rpm gypsumboard screwgun ishelpful when driving the screws used forattaching gypsumboard and sheathing. The nose piece on this type of screwgunwill stop you from driving the screwsthrough the sheathing or gypsumboard.
The proper way to hold the screwgun isto lay your index and second fingeraside the motor housing and use yourthird or fourth finger as the trigger finger(see Photo 5). This will make the gunmore of an extension of your arm than ifyou were to hold it as you would a drill. When driving a self-drilling screw, do notoperate the screwgun at full speed. Bump the trigger until you see metalchips falling away from the screw. Thisis the correct rpm. It will vary dependingon the fastener. These techniques willspeed production and reduce fatigue.
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Other tools include felt markers to markcuts, locking C-clamps to hold steelmembers together during fastening,and "duck-bill" pliers or hand seamersto make bends in track and studs (seePhoto 8). A magnetic level is usefulwith steel framing. It allows both handsto be free while walls are plumbed andfastened.
The majority of fasteners for steelframing are either Phillips or 5/16-inch hex-head screws. You shouldkeep plenty of these bits on site (seePhoto 6).
Magazine or collated attachments arealso available for some screwguns. These can be used for speedingproduction. There are alsopneumatic nailers that drive pins forattaching sheathing in much the sameway that you use a nail gun (seePhoto 7).
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Fasteners
Clinching, pins, welding, and screws haveall been used with steel framing. However, screws are by far the mostcommon fastener for home construction. There are a variety of screws for eachapplication. Only the most common arediscussed here.
Four characteristics of the screw must bematched to the application: size, length,head type, and drill point. The size of thescrew is given as a number designation,i.e., #8, #10, etc. The larger the number,the wider the shank and the stronger thescrew. The size and number of screws inloadbearing walls should be dictated byyour designer or local code. The lengthof your fasteners will be dictated by thethickness of the materials to be fastened. As a rule of thumb for a good connection,there should be at least three exposedthreads through the connected members.
There are many different types of headsfor fasteners. The major categories arethe low-profile and hex-head types (seePhoto 9).
Low-profile heads are preferable insituations where another layer of materialis to be added, such as gypsumboard,sheathing, or siding. Hex-head screwsare easier to drive and can be very usefulwhen trying to get to hard-to-reach areas.
There is also a finishing screw for thefastening of trim and architectural details. This screw has a small head that is easilycounter sunk and will not split or crack thetrim.
The two basic drill points are the sharppoint and the self-drilling (see Photo 10). Sharp-point screws are typically used forattaching gypsum wallboard andsheathing to studs up to 33-mil thick. Forframing connections and attachingsheathing to thicker studs, a self-drillingpoint is used.
As shown in Photo 10, self-drilling screwshave either a smooth shank (pilot point) orsmall wings that protrude above thedrilling tip (winged). The smooth shankon the pilot-point screw allows the drillpoint to penetrate the steel before thethreads engage in the sheathing. Thus,the smooth shank should be slightlylonger than the sheathing. The wingedscrews have wings that clear the materialaround the threads so that the sheathingdoes not climb the threads. The wingsbreak off when they hit the metal and thethreads engage. This allows thesheathing to be pulled tight when thethreads engage in the steel. Table 3summarizes some of the commonfasteners used for various applications.
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Table 3. Typical Fasteners Used with Steel Framing
APPLICATION FASTENER
Steel to Steel Nonloadbearing(less than 33 mils)
Minimum #6, sharp point, low-profile head.
Steel to Steel Loadbearing Minimum #8, self-drilling, low-profile head where gypsumboard orsheathing is to be installed; otherwise, a hex head can be used.
Gypsumboard Minimum #6, sharp point/self drilling1, bugle-head screws.
Interior Trim #6 minimum, sharp point/pilot point,1 finish or trim-head screws. If wood blocking is installed use finishing nails.
Foam Insulation Roofing nails to structural sheathing, or minimum #6, self drilling,bugle head with a washer to prevent the screw from pullingthrough the foam.
OSB/Plywood Minimum #8, sharp point/self drilling1, bugle-head screw. Wingedscrews and pneumatic fasteners are also available.
Stucco Lath Nail lath to wood sheathing or screw through foam backing to studwith #8 minimum drill point, low profile.
Siding Minimum #8, sharp point/self drilling1, bugle head. Wingedscrews are also available.
Brick Ties Minimum #8, sharp point/self drilling1, hex-head screws.
Exterior Trim Minimum #8, sharp point/self drilling1, bugle-head or trim-headfastener.
Steel to Foundation (Slab) Refer to section on Loadbearing-Wall Construction, AttachingLoadbearing Walls to the Foundation or Floor Deck.
1 Use a sharp point for studs up to 33 mils and a self-drilling point for thicker steel.
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INTERIOR NONLOADBEARING-WALL CONSTRUCTION
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Nonloadbearing walls generally consist of 3½-inch, 18- or 27-mil studs and track onspacings up to 24 inches (see Figure 3). Wider studs (5½ inches) will be needed for aplumbing wall. You will need a pair of aviation snips, red and black felt markers,locking C-Clamps, and a screwgun capable of running up to 2500 rpm.
Typical Wall Assembly
Walls can be assembled on the deck and then raised into position (tilt-up framing), orwalls can be built "in-place" by installing the top and bottom track first and then placingthe studs into the tracks.
• Use your black-felt marker to mark the locations of the layout studs (usually at24 inches on center) on the track.
• Use the red-felt marker to mark the location of openings.• Your layout will be more accurate if you mark both tracks at the same time.
For "in-place" framing:
• Use your chalkline to layout location of the walls on the subfloor or slab.• Use a plum-bob and chalkline to mark the location of the walls at the joists or
trusses.• Secure the bottom track to the subfloor with two #8, sharp-point screws every 24
inches.• When securing the bottom track to a concrete slab use two low-velocity, powder-
actuated fasteners every 24 inches.• Use #8 self-drilling screws to secure the top track to each joist or truss.• Where the wall runs parallel to the joists, use pieces of track or "C"-shapes as
blocking every 24 inches (see Detail NB2) as follows:• Cut the blocking two inches longer than the distance between joists. Clip
the flanges back 1 inch to allow the web to lap over the joists.• Secure the blocking on both ends with two #8, self-drilling screws.
• Twist the studs into the track and attach them with a #6 or #8 screw through thetrack into each flange of the stud.
For tilt-up framing:
• Lay the top and bottom track on the floor with stud location marked on each.• Twist the studs into the top and bottom track and clamp them with your locking
C-Clamps.• Tap the track and studs together and fasten studs to tracks.• Use one #6 or #8 screw through the track into the upward-facing flange of the
stud (see Detail NB1).• Fasten all studs on one side of the wall, then flip the wall to fasten the other side
of the flanges.• Once all the members are fastened, the wall can be stood into place, plumbed,
and fastened to the ceiling and floor as required for "in-place" framing.
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Corner Framing
Where two nonloadbearing walls come together to form a corner:
• Attach the web of one end stud into the flange of the other with #8 screws at 24inches on center (see Detail NB3 and NB4).
• An additional stud will be required for gypsumboard installation. It is easier toattach the corners of the walls if this stud is added after the corner is fastened.
Where two walls intersect:
• Use blocking for gypsumboard attachment similar to the blocking used for wallsrunning parallel to joists, or
• Use a six-inch stud turned so that the web is flat against the intersecting walland fasten through one side of the track into the web of the six-inch stud (seeDetail NB5). In a plumbing wall, an eight-inch joist or additional studs would beneeded to form a surface for gypsumboard.
Framing at Openings
When framing a door opening in a nonloadbearing wall:
• Turn the jamb studs so that the solid portion of the web faces the opening. Thisprovides a flat surface on which to fasten a jamb.
• Let the bottom track run continuous through the opening until after the wall is inplace. This will help keep the opening square.
• For the head of the opening, use a piece of 18- or 27-mil track cut two incheslonger than the opening.• With aviation snips, cut the radius (corner) between the flange and web of
the track one inch.• Bend the web towards the flanges with your three-inch seamers (this is
called coping the flange).• Place the track at the height of your opening and fasten to the jamb studs with
one screw in each flange on each side. Install trimmer studs as necessary forgypsumboard layout (see Details NB6).
• When framing an opening you may attach the door directly to the steel studswith screws or install a wood trimmer around the openings. Be sure to leaveadditional space in the opening if you choose to install a wood trimmer.
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LOADBEARING WALL CONSTRUCTION
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Typical loadbearing walls for residential construction are built with 33- to 54-imil studsspaced 16 or 24 inches on center. Tools used for nonloadbearing construction are alsorequired for loadbearing walls. A few additional tools are required for cutting thethicker metal used for bearing walls. A chopsaw with an abrasive bit or a pair ofelectric shears will allow you to make necessary field cuts. Even with these tools, it willbe to your advantage to develop a detailed cut list and have as much of the material aspossible precut. All studs should be precut to length. In addition, some roll-formers willprecut header materials, jack studs, and even trimmer studs.
Design Considerations
The frame of a house provides its structural integrity. This is what enables ahome to withstand the forces of nature. With conventional materials such aslumber and masonry, prescriptive methods have been developed and areincorporated into building codes across the country. There are many charts andtables that represent years of experience, engineering and testing that areincorporated into the codes. As of January 1, 1997, cold-formed steel framingjoined this list of conventional materials. The Council of American BuildingOfficials (CABO) adopted Prescriptive Methods for residential cold-formed steelframed wall and floor assemblies into the 1996 One and Two Family DwellingCode. The Prescriptive Methods were developed by the NAHB Research Centerunder sponsorship of the American Iron and Steel Institute (AISI), theDepartment of Housing and Urban Development (HUD), and the NationalAssociation of Home Builders (NAHB). They include wall stud tables, floor joistspan tables, and fastening schedules which are applicable in most areas of thecountry. In areas recognizing CABO, the Prescriptive Methods should eliminatethe need for engineering calculations for most wall and floor assemblies. A copyof the Prescriptive Methods for Residential Cold Formed Steel Framing can beobtained from AISI (800-79-STEEL).
Layout
Stick Framing usually requires an “in-line” framing technique (see Figure 4). The top and bottom track are not typically loadbearing: therefore, studs, joists,and trusses must be aligned in order to transfer the loads to the member below. Some engineers will design a top track so that the builder will not have to use in-line framing. However, this method uses more steel. Depending on the design,it may be necessary to add additional studs to transfer the load to the nextmember. When marking the track for studs and wall openings, it is necessary totake into account the joist and truss layout order to assure proper alignment ofmembers. Layout of studs, except where required at a wall opening or corner,should all face the same direction. This will make the installation of battinsulation much easier.
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Typical Loadbearing-Wall Assembly
The most common way to build a loadbearing wall is to pre-assemble the wall on thedeck as described below:
• Use your black-felt marker to mark the locations of the layout studs (usually at24 inches on center).
• Use the red-felt market to mark the location of openings.• Your layout will be more accurate if you mark both tracks at the same time.• Where necessary, tracks should be spliced by inserting a section of stud into the
track as shown in Detail LB1.• Twist studs into the tracks and clamp them with your locking C-Clamps.• Next tap the track and studs together and fasten the studs to the tracks. It is
important to get the top and bottom of the studs as tight to the track as possible.• Typical fastening details are similar to those for nonloadbearing walls except
they call for one #8 minimum, self-drilling, low-profile screw on each flange (seeDetail NB1).
• Fasten all studs on one side of the wall, then flip the wall to fasten the otherside. If you are using plywood or other exterior sheathing, it is best to fasten theinterior side of the studs first and then flip the wall and connect the exterior sideto the tracks.
Where members are placed right next to each other they can create a cavity thatcannot be easily accessed. Therefore, you will have to pre-insulate in these areas orcome back later and spray foam into them.
Framing a Wall Opening
There are two types of headers that are commonly used in steel framing: an I-beamheader and a box header. In each case, the number of fasteners will be determined bythe engineer or code.
I-Beam Header (Detail LB2)
• The I-beam header consists of two “C”-sections with the webs screwed back-to-back.
• The size of the header material will be called out by your building code orengineer.
• Two clip angles should be installed as web stiffeners between the lips of the twoheader pieces. (The angles are typically one inch smaller than the web depth.)
• Place the stiffeners flush with each end of the header against the web of theheader material and fasten with #8 minimum, hex-head screws.
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Box Header (Detail LB3)
• The box header consists of the two “C”-sections assembles with the open side ofC”s facing each other.
• The box header should be insulated during wall assembly.• On each end of the header a gusset plate should be installed so that it
overhangs the header material by one inch. As an alternative, you can use C-shapes inside the box attached through the webs to the header and screwed tothe king stud through the flanges.
Header Assembly
• When assembling the wall, mark the rough opening in the track.• With the I-beam header, first position the header in the top track and fasten the
exterior side of the track into the header with screws. Install king studs with thewebs directly against the header and attach the web stiffeners already installedin the header (see Detail LB2).
• With the box header, install the king studs first, then insert the header pieces,and fasten through the gusset or C-shapes into the king studs (see Detail LB3).
• With both types of headers, cut a piece of track two inches longer than theheader and cope the flanges one inch on each end. Center the track on thebottom of the header and fasten it to the header with #8 minimum screws, asrequired.
• Install and fasten the jack studs.
Now trimming out the opening under the header is the same as if it were anonloadbearing wall except the studs are thicker. As with nonloadbearing walls, do notcut the track from the bottom of a door opening until the walls are in place. If you planto use wood around the opening for the attachment of trim, be sure to allow anadditional three inches for the attachment of wood 2 x 4. For doors, only allow 1 ½inches in the height of the opening since a 2 x 4 is not needed at the bottom.
Corner Framing
When framing exterior corners:
• Cut the top track three inches longer on one wall.• Clip the flanges off the three-inch overhang on the inside of the wall.• When the walls are brought together, the web overhang will lay over the top
track of the other wall (see Detail LB4).• Fasten the web overhang into the top of the other wall with four #8 minimum
screws.• Install #8 minimum (3/4 inch), self-drilling screws every 24 inches through the
web of one end stud into the flange of the other (see Detail LB5).
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• Install an extra stud for gypsumboard attachment after the walls are connected. This ensures the proper placement of this stud and keeps it out of the way whenconnecting the walls (see Detail LB5).
Where two walls intersect at an interior corner:
• Use blocking similar to the blocking used for walls running parallel to joists, or• Use a six-inch stud turned so that the web faces the intersecting wall and fasten
through one side of the track into the web of the six-inch stud (see Detail LB6).
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Railing the Walls and Temporary Bracing
• Before the walls are stood into place, square the wall by diagonally measuringthe panel. A “C”-section screwed diagonally to the wall section will temporarilykeep the wall square before and during installation (see Photo 11). Temporarybracing is not needed if plywood or other structural sheathing is applied beforethe walls are stood into place.
• When all walls are raised, bring the corners together, check for plumb, andsecure the walls.
• Once the wall is raised into place, use “C”-sections screwed at the top of the walland secured to the ground in the same manner you would brace a wood frame. These braces should remain in place until permanent bracing or sheathing isinstalled.
• Lastly, adjust the temporary bracing to hold the walls square.• Cut the bottom track at openings with a hack saw or reciprocating saw.
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Attaching Loadbearing Walls to the Foundation or Floor Deck
There are two forces you must account for when attaching walls to the foundation orslab. These forces are shear and uplift. Shear is horizontal movement and uplift isvertical movement. Both of these forces may be induced by wind or seismic events. The most common fastener used to connect steel walls to a concrete foundation is theJ-bolt, although others are available (see Figure 5). J-bolts are pre-cast into thefoundation. A piece of stud can be used as a washer when bolting the walls to thefoundation. Your designer will specify the size and spacing of the fasteners. You maywant to ask your engineer to design using another type of fastener that you are morecomfortable using. Some of these include mudsill anchors, anchor straps, mushroomspikes, drop-in anchors, and powder-actuated fasteners.
When attaching loadbearing walls to a steel-framed floor, drive two pilot-point screwswith a flat head (not a bugle head) through the track at each stud into the joists. Makesure that at least three threads penetrate the joists. If you are attaching walls to awood-framed floor, wood screws can be driven into the band joist. The screws shouldhave a flat bottom on the head (not the countersunk variety). Confer with your designeror code official for the specific fastener type and method.
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Shear Bracing
• First, fasten the strap at the topof the wall.
• At the bottom of the wall fastenone ear to the bottom track andthe other to the bottom of thestrap.
• Close the clamps and draw thestrap tighter in small incrementsuntil the slack is taken out. Oncethe strap is secured this “strapstretcher” can be used again andagain.
• Be careful to not apply too muchtension and pull the wall out ofplumb.
All houses require a certain amount ofshear bracing to resist lateral loads fromwind and/or earthquakes. In many casesthe shear bracing is accomplished withsheathing such as OSB or plywood. Ifyou do not use structural sheathing, steelstraps or other types of shear bracing willbe required (see Detail LB7 and Photo12). The size and location of thediagonal strap and number of screwsrequired are determined by the engineer.
When installing the straps, it isimportant to make sure that they aredrawn tight.
• A pair of locking C-clamps withtwo “ears” made of small strips ofsteel folded and fastened aroundthe jaws of the clamps make anexcellent stretcher for the shearbracing (see Photo 13).
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ATTACHING FINISH MATERIALS
Baseboard and Other Interior Trim
There are several options which may be used to secure trim to steel studs:
• Construction adhesive. Finishing nails driven at criss-cross angles into the trackin pairs will hold the trim firmly in place while the adhesive dries (see Figure 6).
• Self-drilling finishing screws.• A wood nailer may be installed during framing or 2 x 4 blocks may be placed in
the track after the wall is framed. This will allow the trim to be attached withfinishing nails.
Cabinets and Vanities
Just as in wood construction, special consideration has to be made to provide for theinstallation of cabinetry. Use one of the three methods listed below (see Figure 7).
• Use wood blocking between studs. The blocking will have to be notched on oneend at the lip of the stud.
• Use a track with a minimum thickness of 33 mils. Notch the flanges at each studand fasten with two screws.
• Use a steel strip equal to the thickness of the wall stud fastened at each studwith two screws (depending on the thickness of the strap).
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Closet Shelving
To attach wood supports for closet shelving, use bugle-head fasteners. Use sharp-point fasteners for 18- and 27-mil studs and wing-tips for 33-mil and thicker studs. Hex-head or low-profile screws can be used for the attachment of shelving brackets.
Gypsumboard Installation
Installation of gypsumboard on steel walls is very similar to wood construction. Gypsumboard framers in commercial construction have been working with steel studsfor years.
• Hanging gypsumboard on 18- to 33-mil studs will require #6, 1 ¼ -inch bugle -head scews with a sharp-point tip.
• For thicker studs, use a self-drilling #6, 1 ¼-inch, bugle-head screw.• Construction adhesive may also be used.
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UTILITY INSTALLATION
Field Cuts
Pre-punched studs should allow passage for most plumbing and electrical wiring, butthere are usually situations when you will need to make a field cut. Drain, waste, andvent pipe greater than 1 ¾ inches in a 2 x 4 walls or 2 ½ inches in a 2 x 6 wall shouldnot be run through members in a loadbearing wall. Field cuts can be made adhering tothe following:
• Use a stud punch to create a 1 ¼-inch hole.• Holes in studs thicker than 43 mils and larger holes needed for the installation of
drain lines can be made with a hole saw.• Holes should not be closer than ten inches from the top or bottom of the stud.• The top and bottom track may also be cut through the web only.
Limitations on holes in loadbearing members are illustrated in Figure 8. When largerholes are inadvertently made in a stud, a repair is required. This will require a patch ofsheet steel with a minimum thickness equal to the member being repaired. The patchshould be attached with minimum #8 screws every inch along the edges of the patch. Reinforcement details should be approved by the engineer or code official prior to theiruse.
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Plumbing
Hangers
Hangers for plumbing pipes in steel framing should be secured with a ¾ inch, #6 sharp-point screw in 18- and 27-mil studs and a #8, self-drilling screw in thicker studs.
Protection of Plumbing Pipes
Plastic pipe does not need corrosion protection when in contact with steel studs. However, corrosion is a possibility where copper comes in direct contact with the steel. The following methods are recommended:
• Plastic or foam insulators or grommets should be used where copper passesthrough a steel stud. Most just snap in and are universal for all shapes of thepre-punched studs (see Photo 14).
• Where copper pipe runs alongside the studs, wrap the copper with a piece ofpipe insulation.
Attachment of Plumbing Fixtures
Plumbing fixtures can be attached with #10, low-profile screws with a sharp point for18- and 27-mil studs and a self-drilling point for 33-mil and thicker studs.
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Electrical
Wire Protection
Snap-in plastic insulators or grommetsare required to protect the plasticsheathing on electrical wiring from thesharp edges of steel studs. As forplumbing, the majority of these insulatorsare universal for the different shapedpunchouts in the studs (see Photo 15).
Electrical Boxes
• Use electrical boxes that have amounting bracket that attaches tothe side of the stud rather than inthe front. This will prevent bulgesin the gypsumboard (see Photo15).
• Attach the boxes with ¾-inch, #6,sharp-point screws for 18- and 2-mil studs and #8, self-drillingscrews for thicker studs.
Securing Wiring
• For securing multiple wires suchas at a receptacle installation,two ¼-inch holes and a zip tiewill suffice. In some areas,inspectors will accept the use ofduct tape. You should checkwith your electrical inspectorbefore you use this method.
• Where you have many wiresexiting a box, such as in adouble or triple gang box, astandoff clip is the best methodfor securing the wiring (seePhoto 16). These clips can beinstalled with a single ¾-inch, #6, sharp-point screw for 18-and 27-mil studs and #8, self-drilling screws for thicker studs.
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Service Panel
In order to gain a flat surface to attach the service panel, a piece of 18-mil track may beattached over the studs. A wood 2 x 6 may be attached between the studs above thepanel to provide a nailer for securing wiring entering the panel (see Figure 9).
Duct Work
Hangers
Hangers for ducts can easily be attached to steel framing with ¾- inch, #8, self-drillingscrews.
Bulkhead Framing
Although most ducts can be run in attic space, interior walls, or drop down ceilings,occasionally bulkheads will be needed. Where this is desired, this framing is typicallynonloadbearng, and can easily be framed using 33 mil or thinner, “C”-shaped studs andtrack. Sections are assembled the same as walls with #8 self-drilling, low-profilescrews.
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Insulation
All types of insulation, including foam sheathing, batts, and spray-applied foams arecompatible with steel framing. In many climates, a thermal break consisting of foamsheathing is applied to the exterior. Suggested insulation R-values for various areas ofthe country can be found in AISI publication #RG-9405 Thermal Design Guide forExterior Walls. Although spray-applied insulations are installed in much the same wayas with wood framing, some differences in material widths and attachment methods areassociated with batt-type insulations and foam sheathing.
Batt Insulation
Batt-type insulation should be installed as follows:
• Be sure to order full-width batts when installing insulation in steel studs. Battsfor wood walls are typically 14 ½ or 22 ½ inches to allow for the space taken upby the stud. With steel framing the studs are hollow and require a full 16- or 24-inch batt, depending on the stud spacing.
• To install the batt insulation, simply tuck one side of the batt inside the openflange of the stud and press the other side into the wall cavity. Friction shouldhold the batts in place until the gypsumboard is installed (see Photo 17).
• In some cases, duct tape can be used to hold the insulation in place until thegypsumboard is installed.
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Exterior-Foam Insulation
There are three options for installing foam sheathing on steel framed walls:
• Use self-drilling screws with washers to prevent the screw from pulling through.• Use construction adhesive applied to the studs to hold the foam in place before
the siding material is applied.• Use double-sided tape applied to the studs to hold the foam until the siding is
applied.
Where plywood or OSB sheathing is used, roofing nails, screws, or adhesive may beused to attach the foam.
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APPENDIXSAMPLE FLOOR PLAN/CUT LIST
720 Square Foot House
Cut List
No. Qty. Item Mils Length Notes
1. 120 2 x 4 steel stud 33 8’ 0”
2. 30 2 x 4 steel stud 33 7’ 4”
3. 20 2 x 4 steel track 33 30’ 0”
4. 12 2 x 8 steel header 54 4’ 9 ½ “ no holes
5. 10 2 x 8 steel header 54 3’ 9 ½ “ no holes
6. 2 2 x 8 steel header 54 13’ 4 ½ “ no holes
7. 40 2 x 4 steel stud 18 8’ 0” interior walls
8. 20 2 x 4 steel stud 33 10’ 0” interior walls
