Roof Construction Techniques: Pros and Cons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Trusses: Special Benefits for Architects and Engineers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Special Benefits for Contractors and Builders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Special Benefits for the Owner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

How Does A Truss Work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Typical Framing Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Gable Framing Variations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Hip Set Framing Variations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Additional Truss Framing OptionsValley Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Piggyback Trusses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Typical Truss Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Typical Truss Shapes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Typical Bearing / Heel ConditionsExterior Bearing Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Crushing at the Heel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Trusses Sitting on Concrete Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Top Chord Bearing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Mid-Height Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Leg-Thru to the Bearing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Tail Bearing Tray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Interior Bearing Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Typical Heel Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Optional End CosmeticsLevel Return. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Nailer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Parapet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Mansard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Cantilever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Stub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Bracing Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Erection of Trusses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Temporary Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Checklist for Truss Bracing Design Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Floor Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Typical Bearing / Heel Conditions for Floor TrussesTop Chord, Bottom Chord, and Mid-Height Bearing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Interior Bearing Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Ribbon Boards, Strongbacks and Fire Cut Ends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Steel Trusses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Ask Charlie V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Charlies Advice on Situations to Watch Out for in the Field. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Appendix - References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

TTable of Contentsable of Contents

1

Traditional Stick Framing Carpenters take 2x6,

2x8, 2x10 and 2x12 sticks of lumber to the job

site. They hand cut and fit this lumber together

into a roof or floor system.

Timber Frame Craftsmen assemble timbers,

joinery and braces together to form a self-

supporting skeleton structure.

Engineered Wood Products I-Joists, Glulam,

and LVL (laminated veneer lumber) wood products

are shipped to the jobsite, cut to fit, and made into

beams for the floor system, or into ridge beams

and sloping joists for the roof system.

Truss Systems in two primary forms:

Metal Plate Connected Wood Trusses

Engineered trusses are designed and

delivered to the jobsite with a truss placement

plan. Trusses are quickly erected and braced

onsite.

Steel Trusses Light gauge steel trusses are

designed and delivered to the jobsite with a

truss placement plan. Trusses are lightweight,

able to be quickly erected and braced onsite.

Builders, ArBuilders, Architects and Home Owners today have manychitects and Home Owners today have manychoices about what to use in rchoices about what to use in roof and floor systemsoof and floor systems

2

Each method has advantages and disadvantages. In this book we will look at those pros and cons, and assist

you in identifying which method is best for your situation. We hope to be able to offer you strengths for each

system that can help you sell the value-added difference in the product you choose, as well as help you gain

a better understanding of the roof systems themselves, with real world advice on framing techniques and

issues.

________________ ________ PrPros os ________________________

Stick FramingStick Framing

TTimber Frameimber Frame

________________ ________ Cons Cons ________________________

Lowest cost for materials. if you have the time and theskilled labor required.

If trusses cannot be deliveredto the jobsite, conventionalframing may be your onlyalternative.

Slow to install and requiresskilled labor.

May not be accepted by thebuilding department, as it isnot an engineered product.

Requires scarce large lumbersizes (2x8, 2x10)

Smaller span capability.

High jobsite waste.

Creates handsome exposedtimber-frame structures.

Slow to install and requiresskilled labor.

Difficult to run ductwork,wiring, pipes through.

Slow to install and frame in.

Hard to insulate

3

EngineerEngineerededWWood Prood Productsoducts

WWood Tood Trrussesusses

Steel TSteel Trrussesusses

________________ ________ PrPros os ________________________ ________________ ________ Cons Cons ________________________

I-Beams are suitable for steepsloping ceilings.

Trim-able ends on floors, greatfor angled or rounded walls.

Engineered product withuniform quality.

Glulam and Laminated VeneerLumber make strong beammaterial.

Difficult to run ductwork,wiring, pipes through.

Limited use in complicated rooflines, coffered ceilings, etc.

May require special connections.

Lowest overall cost.

Fast to install.

Requires ordinary tools anddoesnt require skilled labor toinstall.

Virtually any roof and ceiling ispossible.

Engineered product.

You will want to plan things inadvance. Youll need a set ofplans for the structure, andyour walls should be close towhere theyre supposed to be.

Lightweight and stiff, soinstalling is easy and fast.

May be preferred in lightcommercial / industrialsettings for fire rating.

Straight ceilings for ceilingattachment.

Virtually any roof and ceiling is possible.

Engineered product.

More expensiv