The Long and Short of Wood Roof Systems

Home , Joist, Purlin, Skylight, Spire, Tongue and groove

Photo Al Karevy/Bensonwood “The Wood Products Council” is This course is registered a Registered Provider with The with AIA CES for continuing American Institute of Architects professional education. As Continuing Education Systems such, it does not include (AIA/CES), Provider #G516. content that may be deemed or construed to be an approval or Credit(s) earned on completion endorsement by the AIA of of this course will be reported to any material of AIA CES for AIA members. construction or any method Certificates of Completion for or manner of both AIA members and non-AIA handling, using, members are available upon distributing, or dealing in request. any material or product. ______Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Course Description

This course is an overview of the many framing systems commonly used in buildings in the United States for a variety of span lengths. The presentation will review the possible wood structural framing systems including rafters, metal plated wood trusses, engineered wood products and hybrid roof systems. Also covered will be how these components can be combined to create efficient and versatile roof framing systems. All of these concepts will be reinforced through the presentation of real example projects with details on the framing system used to achieve the project goals. Learning Objectives

1. Participants will be familiar with wood framing options available for use as roof framing and be able to evaluate different framing systems to use for building projects 2. Participants will be familiar with the variety of roof geometries that are possible with wood framing systems 3. Through the presentation of several project case studies, the participant will understand how long span roof systems can be built from all wood and hybrid wood structural configurations 4. Participants will be familiar with the International Building Code provisions that allow the use of wood systems in many roof applications including use in non-combustible Type I and Type II construction buildings Wood Roof Riding Arena Christ the King Catholic Church

Christ the King Catholic Church Hamilton, GA Architect: CDH Partners, Inc. Engineer: KSI Structural Engineers

Timber trusses and wood decking Spire created unique skylight effect Outline

• Wood Roof Components • Wood Roof Systems • IBC Code Provisions for Wood Roofs Components of Roof System? Wood Roof Sheathing Options

Wood Structural Panels Oriented Strand Board (OSB) and Plywood Solid Sawn Decking 2x, 3x and 4x dimensional lumber Mechanically Laminated or Tongue & Groove Panel Products: Structural Insulated Panels (SIPS) Cross-Laminated Timber (CLT) Panels Wood Structural Panels

Plywood - the original engineered wood panel (>100 years)

Oriented Strand Board (OSB) - a second generation engineered wood panel (>25 years) IBC 2012 2303.1.4 Wood structural panels.

Wood structural panels, when used structurally (including those used for siding, roof and wall sheathing, subflooring, diaphragms and built-up members), shall conform to the requirements for their type in DOC PS 1, DOC PS 2 or ANSI/APA PRP 210. Each panel or member shall be identified for grade, bond classification, and Performance Category by the trademarks of an approved testing and grading agency. The Performance Category value shall be used as the “nominal panel thickness” or “panel thickness” whenever referenced in this code. Wood structural panel components shall be designed and fabricated in accordance with the applicable standards listed in Section 2306.1 and identified by the trademarks of an approved testing and inspection agency indicating conformance to the applicable standard. In addition, wood structural panels when permanently exposed in outdoor applications shall be of Exterior type, except that wood structural panel roof sheathing exposed to the outdoors on the underside is permitted to be Exposure 1 type. APA Engineered Wood Construction Guide Lumber Decking

Code Acceptance for 2, 3 and 4 inch thick Tongue & Groove Lumber Decking per IBC 2012 2304.8

2x6 T&G Doug Fir 3x6 Double T&G Pine Photo Bear Creek Lumber Photo Southern Wood Specialties Lumber Decking Layup Options

Details in IBC with further information in AWC WCD 2

American Wood Council Wood Construction Data 2 Tongue and Groove Roof Decking Christ the King Catholic Church

Christ the King Catholic Church Hamilton, GA Architect: CDH Partners, Inc. Engineer: KSI Structural Engineers

Timber trusses and wood decking Spire created unique skylight effect Lumber Roof Decking Spans

• 2 inch can span up to 8 feet or more • 3 inch can span up to 12 feet or more • 4 inch can span up to 16 feet or more • Spans depend on Loads, Species and Grade of Lumber, Deck Layup Pattern, Acceptable Deflection, etc. Diaphragm Sheathing Limitations

• IBC 2012 2306.2 applies to wood-framed diaphragms and references AWC Special Design Provisions for Wind & Seismic 2008 (SDPWS): • Example capacities are: Diaphragm Max Aspect Max Possible Allowable Shear Type Ratio Capacity (ASD) in SPDWS Lumber Sheathing

Horizontal 2x sheathing 2:1 VW=70 plf, VS=50 plf

1 layer Diagonal 2x sheathing 3:1 VW=420 plf, VS=300 plf

2 layers Diagonal 2x sheathing 4:1 VW=840 plf, VS=600 plf Wood Panels

Blocked WSP* 4:1 VW=2520 plf, VS=1800 plf

Unblocked WSP 3:1 VW=447 plf, VS=320 plf

*Maximum value from high load diaphragms Structural Panels Over Decking

Panel Installation Requirements • Panel Edges must not coincide with decking joints • Panel edges must be attached to common member • Minimum fastener penetration must be provided • Maximum 4:1 aspect ratio is allowed. • A complete load path must be provided for forces

Additional information can also be found in: • APA Form TT-097 Designing Diaphragms Over Existing Board Floors or Roofs • ATC 7 Guidelines For The Design of Horizontal Wood Diaphragms Components of a Wood Roof System

Structural Framing Rafters and Purlins Ithaca Foreign Car

Ithaca Foreign Car Repair Photos courtesy New Energy Works Timberframers Solid Sawn Roof Framing

Design Routes: IBC 2012 2308 – Conventional Light-Frame Construction AWC NDS 2012 – Engineered Design AWC Wood Frame Construction Manual 2012 - Design tools based upon NDS Glulam

Glulam What is Glulam?

Glulam = a structural composite of lumber and adhesives Spans of 100 feet or greater achievable

12-1/4” x 84” 140 ft. clear span Camber = 8” Flexibility of Shapes and Spans Promega Feynman Center, The Crossroads, Madison, Wisconsin ARCHITECT: Uihlein-Wilson Architects, Inc. ENGINEER: EwingCole DESIGN CONSULTANT: Archemy Consulting PHOTOS: Aitor Sanchez/EwingCole Promega Feynman Center, The Crossroads, Madison, Wisconsin Photos: Aitor Sanchez/EwingCole Pre Fabricated Wood I-Joists

Recognized in IBC 2303.1.2 using ASTM D 5055 Proprietary Products with Evaluation Reports SCL or lumber flanges

Structural Structural glue joints wood panel web Havens Elementary School, Piedmont CA Design : ATI Architects and Engineers 46,000 sf school replacement General Contractor: Webcor Completed 2010 Photos Janelle Leafblad/WoodWorks Havens Elementary School, Piedmont CA Design : ATI Architects and Engineers 46,000 sf school replacement General Contractor: Webcor Completed 2010 Photos courtesy RedBuilt Structural Composite Lumber

Laminated Parallel Laminated Oriented Veneer Strand Strand Strand Lumber Lumber Lumber Lumber University of Idaho Recreational Center 85,000 sq ft Architects: Ohlson Lavoie Company Completed 2002 Structural Engineer: Coffman Engineers PSL Truss Roof Outline

• Wood Roof Components • Wood Roof Systems • IBC Code Provisions for Wood Roofs Metal Plated Wood Truss Truss Configurations

Parallel chord or flat truss

37 Truss Configurations

Scissors Studio Vault

Vaulted Parallel Chord Tray or Coffer

Flat Vault Barrel Vault 82’ Clear Span Trusses 90’ Clear Span Glulam Trusses Cayucos Elementary K- 8

Location: Cayucos, CA

Completed: 2009

Architect: RRM Design Group

Panelized Roof System

ØPre-fabricated roof sections lifted into place ØSafety, cost, speed

Ø Two common types § All wood § Hybrid When are Panelized Roofs used?

Most commonly with tilt-up concrete or masonry walls

Typical for large, low slope, roof structures How is a Panelized Roof Constructed?

1 Column erection

2 Girders placement

3 Purlin installation How is a Panelized Roof Constructed?

Panels are assembled on the 4 ground (often 8’ width) •Single purlin •Sub-purlins or stiffeners spaced @ 24”oc •Plywood or OSB HowHow is ais aPanelized Panelized Roof Roof Constructed? Constructed

5 Pre-framed panel placement How is a Panelized Roof Constructed?

Pre-framed panel secured •Purlin to girder 6 •Sub-purlins to purlin •Final panel nailing

7 Process repeated Panelized System Elements

Pre-framed Panel

Wood Structural Panel Sheathing Ø4x8, 4x10, or 8x8 jumbo panels ØOSB or plywood

Purlin

Subpurlin 2 ½” Glulam, I-joist, Open-web truss Open-web wood flange, steel joist Dimensional sawn lumber Defining Panelized System Elements

Pre-framed panel

Girder Girder Simple span or Cantilevered Glulams Panels span between girder lines

WoodWorks Case Study

• Introductory Piece • 4 Case Studies • Highlights Benefits • Cost • Schedule • Safety • Demonstrates Variety • states/climates • Occupancies • Construction applications Design Examples “Our total installed cost [was] $5.49 per square foot, where a similar steel system would have been $6.00 to $7.25” - John Mandere, Mandere Construction, the Roof Erector

Freedom Truck Center, Spokane, WA 45,000 sq ft Architects: ALSC Architects Panelized Roof Structural Engineer: DCI Engineers Photos courtesy RedBuilt Light House Baptist Church Multi-Purpose Building 90 ft span Architect: Cliff Paris Gym on 2nd Floor Structural Engineer: Manning Engineering Photos courtesy RedBuilt Timber Frame Systems

SIMPLE TRUSS CLASSIC KING POST TRUSS KING POST TRUSS

SCISSOR TRUSS QUEEN POST SYSTEM HAMMER TRUSS 25,000 sq ft William N. Allyn Conference Center Photos courtesy New Energy Works Timberframers 25,000 sq ft William N. Allyn Conference Center Photos courtesy New Energy Works Timberframers 25,000 sq ft William N. Allyn Conference Center Photos courtesy New Energy Works Timberframers Burr & Burton Academy – Mountain Campus LEED Platinum – Net Zero Photos Al Karevy. Courtesy Bensonwood 15,000 sf Type VA Structure Whole Foods Market 67’ Span Glulam trusses @ 14’ o.c. & 2x6 T&G SP Deck Atlanta, GA On glulam beams and 8x8 Columns @ 20 ft o.c. Glulam Arches Lemay America Auto Museum 104’ Span Glulam Arches Photos courtesy Western Wood Structures Glulam purlins @ 4’ o.c YMCA Camp Thunderbird Duke Energy Pavilion Lake Wylie, South Carolina ENGINEER: Bulla Smith Design Engineering PHOTOS: Stanley Capps YMCA Camp Thunderbird Duke Energy Pavilion, Lake Wylie, South Carolina Photos: Stanley Capps Duke Lower and Middle School

Location: Durham, NC

Completed: 2009

Architect: DTW Architects and Planners Raleigh Durham International Terminal 2 Up to 136 ft spans Lead Architect: Fentress Architects Hybrid Glulam Truss Lead Structural: ARUP Completed 2010 Photos courtesy Structurlam Products University Laval Soccer Stadium, Quebec City Architect: ABCP Architecture + urbanisme 216 ft span Photos courtesy Nordic Engineered Wood Products University Laval Soccer Stadium, Quebec City Architect: ABCP Architecture + urbanisme 216 ft span Photos courtesy Nordic Engineered Wood Products Outline

• Wood Roof Components • Wood Roof Systems • IBC Code Provisions for Wood Roofs IBC Conforming Routes to Wood Roofs

Qualify Whole Building for Construction Type, III, IV or V:

1) Type III, IV or V construction per IBC 2012 Section 503, Table 503 and the allowable heights and areas modifications for sprinklers, etc.

2) Type III, IV or V construction per Unlimited Area options in Section 507 2012 Code Conforming Wood Design Pop Quiz

What is the maximum possible area allowed in IBC 2012 for a wood 1 story Education occupancy building with sprinklers? Unlimited Area IBC 2012 507.10, Type IIIA or IV Construction

What is the maximum possible area allowed in IBC 2012 for a wood 2 story B, M, F, or S occupancy building with sprinklers? Unlimited Area IBC 2012 507.4

Assembly occupancies options as well. Buildings required to have surrounding public ways and/or yards. See IBC 507 for specific requirements. Unlimited Area Buildings

IBC 2012 Section 507 gives Unlimited Area Building routes for Type III, IV and/or V Construction for the following occupancies: Assembly Education Business Factory Mercantile Storage IBC Conforming Routes to Wood Roofs

Wood Roofs Allowed in other Construction Types 1) Footnote b of Table 601 (FRTW when > 20 ft) 2) Footnote c of Table 601 (HT when 1hr or less Required) Fire Resistance Rating -IBC Table 601

b. Except in Group F-1, H, M and S-1 occupancies, fire protection of structural members shall not be required, including protection of roof framing and decking where every part of the roof construction is 20 feet or more above any floor immediately below. Fire-retardant-treated wood members shall be allowed to be used for such unprotected members. c. In all occupancies, heavy timber shall be allowed where a 1-hour or less fire- resistance rating is required. Type IV Construction Heavy Timber

Heavy Timber (HT) has … • Exterior walls made of noncombustible materials or fire-retardant-treated wood (FRTW) • Interior building elements of heavy timber or laminated wood meeting minimum dimensions and without concealed spaces HT Minimum Sizes – Roof Framing

602.4.9 Exterior structural members – Beam Supporting Where horizontal separation of 20 ft is Roof Load provided, heavy timber wood columns > 4x6 nominal and arches are permitted externally.

Column Supporting Roof Load > 6x8 nominal

Photo of Hoffstadt Bluff Visitor’s Center Minimum Sizes – Roof Framing

Roof Decking > 2x T&G Deck Ø 1-1/8” WSP Ø 3x on edge-planks Ø CLT

Truss Framing > 4x6

Photo of Hoffstadt Bluff Visitor’s Center Questions?

This concludes The American Institute of Architects Continuing Education Systems Course

Wood Project Assistance [email protected]

WoodWorks Website www.woodworks.org Photo New Energy Works Timberframers Copyright Materials

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