All Wood and Hybrid All-Wood and Hybrid Panelized Roof Systems

Presentation Overview

. Definition of Panelized Roof System . Historical Background . How to construct a panelized roof . Defining System Elements All-wood and Hybrid . How to Design a Panelized Roof Panelized Roof Systems . Preliminary layout and sizing . DiiDesigning fltlldfor lateral loads A Value Added Approach . Frequently Asked Questions . Structural FAQ Lisa Podesto, PE WoodWorks for Non-residential Construction . Fire protection FAQ . Construction FAQ

Presentation Overview What is a Panelized Roof?

. Definition of Panelized Roof System  Pre-fabricated roof . Historical Background sections lifted into place . How to construct a panelized roof  Safety, cost, speed . Defining System Elements . How to Design a Panelized Roof . Preliminary layout and sizing . DiiDesigning fltlldfor lateral loads . Frequently Asked Questions . Structural FAQ  TtTwo common types . Fire protection FAQ . All wood . Construction FAQ . Hybrid When are Panelized Roofs used? When are Panelized Roofs used?

 Most commonly with tilt-up concrete or masonry walls

 Typical for large, low slope, roof structures

When are Panelized Roofs used? Panelized Roof History Lesson

Open web Improved "F" Hanger Wood I-joist steel Installation girders

1960 1970 1980 1990 2000

•Cantilevered Open web Warehouse beams Oriented wood Docking •2½2 ½” glulam Strand trusses Bays purlins Board How is a Panelized Roof Constructed? How is a Panelized Roof Constructed?

1 Column erection

4 Panels are assembled on the 2 Girders placement ground (8’ width x __ length) •Single purlin •Sub-purlins or stiffeners spaced @ 24”oc 3 Purlin installation •Plywood or OSB

How is a Panelized Roof Constructed? How is a Panelized Roof Constructed?

5 Pre-framed panel 7 Pre-framed panel secured construction •Purlin to girder •Sub-purlins to purlin •Final panel nailing

6 Pre-framed panel placement 8 Process repeated Defining Panelized System Elements Defining Panelized System Elements

Pre-framed Panel Pre-framed Panel Purlin  2 ½” Glulam, I-joist, Open-web truss  Open-web steel joist Wood Structural  Stiffeners attached with joist hangers Panel Sheathing

Purlin Purlin

Subpurlin / Stiffner

Defining Panelized System Elements Defining Panelized System Elements

Pre-framed Panel Pre-framed Panel

APA Sheathing

Jumbo panel

APA Sheathing SbSub purlin / Stiffener  4x8, 4x10, or 8x8 jumbo panels  3x6/2x6 lumber  OSB or plywood Sub purlin /  Spaced at 24” oc Stiffener Defining Panelized System Elements Presentation Overview

. Definition of Panelized Roof System . Historical Background . Defining System Elements Pre-framed . How to construct a panelized roof panel . How to Design a Panelized Roof . Preliminary layout and sizing . DiiDesigning f or l ltlldateral loads Girder . Frequently Asked Questions Girder . Structural FAQ  Simple span glulam (or Cantilevered Glulam) . Fire protection FAQ  Open-web steel joist . Construction FAQ  Pre-framed panel spans between girder lines

Terminology: Purlins Terminology: Hybrid

. All Wood Panelized Roof . Hybrid Panelized Roof . Sub-purlins and purlins are wood . Purlins and girders are steel elements . Sub-purlins are often wood . Girders are solid or engineered wood . Decking is always wood . Decking is always wood structural panel structural panel . Glulam Purlin . K-Series** . Short span . Ex: 20K5 or 20K240/128 . LH-Series** . Long span . Ex: 32LH10 or 32LH310/160 . G-Series** . Girders . Open Web Wood Truss Purlin . I-Joist Purlin **Steel Joist Institute Specifications Where to start: Preliminary Design Methodology Where to start: Preliminary Design Methodology

Assumptions: Assumptions: •DL= 12-18 lb •DL= 15 lb •LL= 20 lb •SL= 40 lb (reducible) span span

Purlin Purlin All Wood – Typical Purlin All Wood – Typical Purlin Most Economical Maximum Most Economical Maximum Type Span DthDepth Span DthDepth Type Span DthDepth Span DthDepth I-joist 30’-35’ 20”-24” 38’ 30” I-joist 22’ 28” 25’ 30” Bar Open -web 30’-40’ 40” 55’ 60” Bar Open-web 30’ 50” 36’ 50” Wood Open-web Up to 55’ 44”-48” 65’ 66” Wood Open-web 32’ 40” 37’ 50”

Span dictates column/grid spacing. Span dictates column/grid spacing.

Where to start: Preliminary Design Methodology Where to start: Preliminary Design Methodology

Assumptions: Assumptions: •DL= 12-18 lb •DL= 12-18 lb •LL= 20 lb •SL= 40 lb (reducible) span span

Purlin Purlin Hybrid– Typical Purlin Hybrid– Typical Purlin Economical Type Span [ft] Resources Economical Depp[]th [in] Type Span [ft] Resources Depth [in] Span[ft]/2 + 6 K-series Less than 48’ Min= Span/2 “Proper Selection, Specification and seismic K-series Less than 48’ Span/2+12 “Proper Selection, Specification and seismic Details of Open-Web Steel Joist Framing for Details of Open-Web Steel Joist Framing for Span[ft]/2 + 6 Roof in California” by Darrell Marchell LH-series More than 48’ Span/2+12 Roof in California” by Darrell Marchell LH-series More th an 48’ Min=Span/2 Where to start: Preliminary Design Methodology Where to start: Preliminary Design Methodology

Assumptions: Assumptions: •DL= 12-18 lb •DL= 12-18 lb •LL= 20 lb •SL= 40 lb span (reducible) span

Rule of Thumb: Rule of Thumb: Glulam’s Max depth ~ 10 x width Glulam’s Max depth ~ 10 x width

All Wood – Typical Girder All Wood – Typical Girder Most Economical Maximum Most Economical Maximum DthDepth DthDepth DthDepth DthDepth Type Span Span Type Span Span 8 ¾” 6 ¾” 5 1/8” 8 ¾” 6 ¾” 5 1/8” 8 ¾” 6 ¾” 5 1/8” 8 ¾” 6 ¾” Glulam (24F) 30’-40’ 20-24” 24-30” 30-36” 50’ 42” 48” - Glulam (24F) 32’ 28.5” 33” 39” 39’ 45” 45” HSC (32F) 35’-45’ 18-24” 22-28” 28-36” 50’ 36” 42” 48” HSC (32F) 40’ 33” 39” 45” 50’ 51” 57”

Where to start: Preliminary Design Methodology Where to start: Preliminary Design Methodology

Assumptions: •DL= 12-18 lb •LL= 20 lb span (reducible) Y

Diaphragm Girder

X Hybrid– Typical Girder Overall Building Size Type Span [ft] Economical resources Depth [in] System Max Ratio X:Y G-series Up to 120’ Span[ft] + 8 “Proper Selection, Specification and seismic All Wood 4:1 Details of Open-Web Steel Joist Framing for Typical=32’-60’ 72” max Roof in California” by Darrell Marchell Hybrid 4:1 CBC 2305.2.3 - When ratio exceeds 4:1, internal bracing is required. How to design for lateral loads How to design for lateral loads

Braced Frames Diaphragm Design  Interior shear resistance  Calculation Methods that reduce building costs should be provided  High Load Diaphragm Table when:  Sub-diappghragm Desi gn  Diaphragm ratio exceeds 4:1  Collective Chord Design  Exterior wall can not  Diaphragm Deflection handle loading

How to design for lateral loads How to design for lateral loads

High Load Diaphragm Design Normal Diaphragm Design

 New Table 2306 .3 .2 in 2007 CBC/2006 IBC Connections required for  Based on APA full scale testing each line of sub-purlins  APA report 138

 ES 1952 now incorporated in code Lateral  3x normal diaphragm shear values Load  up to1800 plf (seismic), 2520 plf (wind) = 1800  40% increase for wind loads connections  All edges are blocked  8’-10’ panel width with purlins at each end  Utilizes multiple rows of nails How to design for lateral loads How to design for lateral loads

Sub-Diaphragm Design Normal Diaphragm Design

TilldtTypical load transf er

Lateral Lateral Load Load Connections required for = 102 each line of purli ns connections

Aspect ratio 2.5:1 max.

How to design for lateral loads How to design for lateral loads

Traditional Chord Design Collective Chord Design

Lateral Load Lateral Load

 Works well on small and moderate  More economical on large buildings size buildings  Realistic way to model chord action How to design for lateral loads How to design for lateral loads

Traditional Chord vs. Collective Chord Multiple Nailing Zones Based on 8’ oc tie spacing

3 X Y Traditional Collective

62kips6.2 kips 120’ 160’ 19 kips X max 1 2 4 21 4.5 kips 400’ 400’ 40 kips max 9.0 kips 750’ 1100’ 211 kips max Y  Economizes on material and time  Less nails Results of Example done by Kramer and Lawson  Less nailing time

How to design for lateral loads How to design for lateral loads

Diaphragm Deflection Calculations Calculation Methods Resources/Examples  Two Equations to choose from HihLHigh Loa dDid Diap hragm -CBC table 2306. 3. 2 &  2006 IBC – traditional equation -Diaphragms and Shear Walls  2005 AF&PA NDS – simplified equation **suggested you Design/Construction Guide -APA form L350A use this equa tion ** Sub-Diaphragm -Diaphragms and Shear Walls  Collective Chord Modification Design/Construction Guide -APA form L350A -Lateral Load Connections for Low-Slope  Reduces diaphragm deflection calculations RfDihRoof Diaphragms – APA Form No. Z350A  Complicates equation for moment of inertia Collective Chord -“Thinking Outside the Box: New approaches  See John Lawson’s paper for resulting equation to very large flexible diaphragm” by John  Multiple nailing zones Lawson  More accurate deflections when taken into account Diaphragm Deflection -“Thinking Outside the Box: New approaches to very large flexible diaphragm” by John  Using virtual work method, equation is derived for you in Lawson John Lawson’s paper Presentation Overview Frequently Asked Questions: Structural

1. Is wind uplift an issue? . Definition of Panelized Roof System 2. Are snow loads an issue? . Historical Background 3. Are expansion joints needed? . Defining System Elements 4. Are there resources for detailing . How to construct a panelized roof connections? . How to Design a Panelized Roof . Preliminary layout and sizing . DiiDesigning fltlldfor lateral loads . Frequently Asked Questions . Structural FAQ . Fire protection FAQ . Construction FAQ

Frequently Asked Questions: Structural Terminology

1. Is wind uplift an issue? No . Factoryy()p Mutual (FM) provides: The attachment of the wood roof deck to the framing is highly . Property insurance for commercial and industrial buildings resistant to fatigue failure. . Engineering-driven underwriting . Risk management solutions Panelized Roof Assemblies have been tested to meet . Property loss prevention research Underwriters Laboratories (()UL) and Factor y Mutual ( FM) . www.fmglobal.com wind uplift ratings to comply with insurance requirements. . FM approved systems don’t have to be designed into Resource: Wind Rated Roofs APA Form No. G310A every building. . FM pro v ides a tool called “RoofNav” Engineers need to provide adequate attachment from the . Free online database of FM approved roof assemblies approved assemblies to the walls and supports. Frequently Asked Questions: Structural Frequently Asked Questions: Structural

2. Are snow loads an issue? No 3. Are expansion joints No needed? Engineers may need to do a snow drift calculation per ASCE Roof expansion joints can be eliminated as thermal 7-05 section 7.7.1. exppgyansion of the wood roof deck during cyclical temperature is negligible. Depending on parapet height, there may be increased loads This also simplifies the wind analysis as a it conforms to the attht the roof peri met er whi hihch may requ ire: Simp lifie d Low Rise proce dure can be use d. • Larger sub-purlins at perimeter Resource: ASCE 7-05 Section 6.4 • Greater load capacity hardware Panel buckling is addressed with certain construction • Thicker sheathing to accommodate span rating techniques. requirements Resource: Minimizing Buckling of Wood Structural Panels in High risk Applications – APA Form No. X480

Frequently Asked Questions: Structural Frequently Asked Questions: Fire

4. Are there resources for Yes 1. Can panelized roofs be used in types I detailing connections? and II construction? 2. Is Fire Retardant Treated wood required? The APA produces a document which includes details for all 3. Does the use of a panelized roof reduce wood roofs. the allowable area? Resource: Connections for Low Sloped Roofs, 4. Are fire sppqrinklers required? APA Form No. Z350 5. Is a panelized roof more expensive to VULCRAFT produces a document which includes many insure? hybrid panelized roof details. Resource: Open Web Steel Framing for Wood Roofs Frequently Asked Questions: Fire Frequently Asked Questions: Fire

1. Can panelized roofs be used Yes 1. Can panelized roofs be used in types I in types I and II construction? and II construction? Yes

TABLE 601 TABLE 601 FIRE‐RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS (hours)(hours) FIRE‐RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS (hours)(hours) TYPE I TYPE II TYPE III TYPE IV TYPE V TYPE I TYPE II TYPE III TYPE IV TYPE V BUILDING ELEMENT ABAe B Ae BHTAe B BUILDING ELEMENT ABAe B Ae BHTAe B g pp g g pp g RoofBi constructionll RoofBi constructionll Including supporting beams 1 1/2c 1c, d 1c, d 0c, d 1c, d 0c, d HT 1c, d 0 Including supporting beams 1 1/2c 1c, d 1c, d 0c, d 1c, d 0c, d HT 1c, d 0 c. Except in high rise buildings, Group A, E, F-1, H, I , L, M, R-1, R-2 and S-1 occupancies, fire c. Except in Group F-1, H, M and S-1 occupancies, fire protection of structural protection of structural members shall not be required, including protection of roof framing members shall not be required, including protection of roof framing and decking and decking where every part of the roof construction is 20 feet or more above any floor where every part of the roof construction is 20 feet or more above any floor immediately below. For high-rise buildings, Group A, E, I, L, R-1 and R-2 occupancies and other applications listed in Section 111 regulated by the Office of the state Fire Marshal, fire protection of members other than the structural frame shall not be required, including immediately below. Fire-retardant-treated wood members shall be allowed to be protection of roof framing and decking where every part of the roof construction is 20 feet or more above any floor immediately below. Fire- used for such unprotected members. retardant-treated wood members shall be allowed to be used for such unprotected members. d. In all occupancies, heavy timber shall be allowed where a 1-hour or less fire- d. In all occuppyancies, heavy timber shall be allowed where a 1-hour or less fire-resistance rating resistance rating is required. is required.

Frequently Asked Questions: Fire Frequently Asked Questions: Fire

2. Is Fire Retardant Treated No 3. Does the use of a panelized (FRT) Wood required? roofdf reduce the allowabl e area? No

Fire retardant treated wood is not required; however, it may be used if the following conditions exist: In Occupancy Groups most commonly using panelized roofs, there is no disadvantage in allowable area due to the roof • Type IA (2 stories or less) when the roof is less than system. 20’ from the floor below. • Unlimited Area (507 of IBC 2006): • Type IB (2 stories or less), IIA, IIIA & VA when the roof is less than 20 ’ from the floor below. Heavy • 1 story, unsprinklered, Group F-2 or S-2, 60’ clear all Timber construction (Type IV) can be used in this sides condition as well. • 1 story, sprinklered, Group B, F, M, or S, 60’ clear all • See 603. 1. 3 of IBC 2006 sides Frequently Asked Questions: Fire Frequently Asked Questions: Fire

4. Are fire sprinklers required? No

The International Building Code does not require fire sprinklers. Sprinkling a building can increase the allowable area of your building by up to 300% per IBC 2006 Section 506.3 . Area increase exceptions are: • Buildings more than 1 story above grade = 200% increase • Only in non high-rise Group A, E, H, I, L and R may the area increase be taken in addition to the height and story increase • Area increase doesn’t apply to Use Groups H1, H2 and H3, or Group L. • When the fire-resistance rating substitution is taken

Frequently Asked Questions: Fire Frequently Asked Questions: Fire

The International Building Code does not require fire Sprinkler lines and other mechanical equipment can be easily spppggrinklers. Sprinkling a building can also allow a reduction attached to the wood framing. in fire rating requirements. Resource: Sprinkler Installation for APA Performance

TABLE 601 Rated I-Joists, APA Form No. H730 FIRE‐RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS (hours)(hours) TYPE I TYPE II TYPE III TYPE IV TYPE V BUILDING ELEMENT ABAe B Ae BHTAe B g pp g RoofBi constructionll Including supporting beams 1 1/2c 1c, d 1c, d 0c, d 1c, d 0c, d HT 1c, d 0 e. An approved automatic sprinkler system in accordance with Section 903.3.1.1 shall be allowed to be substituted for 1-hour fire-resistance-rated construction, provided such system is not otherwise required by other provisions of the code or used for an allowable area increase in accordance with Section 506.3 or an allowable height increase in accordance with Section 504.2. The 1-hour substitution for the fire resistance of exterior walls shall not be permitted. Frequently Asked Questions: Fire Building Size Example I

5. Is a panelized roof more No . Assume: expensive to insure? . Office building . Roof less than 20’ from floor below . Concrete walls The i nsurance diff eren tia l be tween a me ta l roo f an d a woo d . No area increase due to frontage roof is small, if any, among informed insurance agents. TABLE 503

TYPE OF CONSTRUCTION There are Factory Mutual guidelines to follow that will help TYPE I TYPE II TYPE III TYPE IV TYPE V AB A B A B HTA B reduce the cost of insurance premiums. HGT (S) h//flbl/http://www.fmglobal .com/page.aspx?id=50050000 GROUP HGT (feet) UL 160 65 55 65 55 65 50 40 S UL1154545 32 B A UL UL 37,500 23,000 28,500 19,000 36,000 18,000 9,000

Allowable Areas Frequently Asked Questions: Construction

Allowable Area

Allowable Area (ft2) Building Type Nonsprinklered(a) Sprinklered(b)(c) 1. AthiAre there issues with connecti tifon of roofi ng material? IB Unlimited Unlimited 2. Is moisture, drainage or ponding an issue? 3. Are there advantages to using skylights? IIA 37,500 112,500 4. What is the best way to insulate a wood deck? IIB 23, 000 69, 000 5. Are there advantages for the contractor? 6. Do panelized roofs contribute to a “green” (a) Fire Retardant Treated (FRT) or Heavy Timber (HT) required building? (b) Sprinklers used to increase allowable area (c) Fire Retardant Treated (FRT) or Heavy Timber (HT) not required 7. How does a panelized roof contribute to cost savings? Frequently Asked Questions: Construction Frequently Asked Questions: Construction

1. Are there issues with connection 2. Is moisture, drainage or ponding No of the roofing materials? No an issue?

Roofing can be directly attached to the roof deck, eliminating Wood roof decks allow compound slopes and abrupt slope the need for rigid insulation. changes to be more easily incorporated for roof drainage, thus eliminating the need for costly crickets and sloped insulation. Drive screw nails virtually eliminate “nail pop” issues associated with 10d smooth shank nails. Using a slope of ¼” per 1’ will eliminate the need for ponding calculations. Section 1611.2 in IBC 2006

Frequently Asked Questions: Construction

Effects from moisture seen during construction can be Drainage is not an issue when properly designed for. Sloped controlled. ledgers at the wall are suggested in place of cricketing. APA EWS R525B - Moisture Control in Low Slope Roofs During Design: During Construction: • Provide positive roof slope ½:12 • Install roofing soon after deck • Specify glulam and dry lumber installation • Cut back ends of reflective foil and • Delay installation of below-deck insulation below sheathing by ½” insulation until MC is less than 18% • Consider insulation above wood deck • Provide ventilation to remove moisture in low temperature zones or high from concrete curing and gypsum joint interior humidity During Service: • Specify vapor barrier with gravel layer • Maintain roof membrane • Design HVAC system to maintain • Maintain HVAC indoor winter humidity levels • Prevent nails, screws and connectors • For buildings with high natural from protruding above the surface of moisture production , use preservative the roo f d ec k Typical Drainage Plan treated wood Frequently Asked Questions: Construction Frequently Asked Questions: Construction

3. Are there advantages to using Yes The use of skylights reduces the need for electrical skylights? illumination saving on energy costs.

Roof ppygpenetrations for skylights and downspouts are more easily flashed since all openings are framed using wood construction.

Skylight installation costs are 1/3 less when using a wood roof instead of a steel roofs. Sky lig hts can be eas ily des igne d for as per fora tions in the diaphragm. Thinkinggppyg Outside the Box: New approaches to very large flexible diaphragms by John Lawson, SE

Frequently Asked Questions: Construction Frequently Asked Questions: Construction

4. What is the best way to insulate a 5. Are there advantages for the Yes panelized roof? contractor?

The use of batt insulation can save $0.50-$1.00/sf over the Speed of Erection use of ri g id insu la tion. One o f the a dvan tages to a • Typical panel can be built and lifted into place in 4-5 min. panelized roof is that it can be insulated below the wood • 100,000 sf warehouse takes approx. 3 weeks to erect deck with batt insulation. • Panelized Roof specialists can be located on the Structural Roof Erectors’ Association website Above deck, rigid insulation should be considered in areas Jobsite Safety of cold ex teri or tempera ture or hi hihidgh indoor hum idity. • Only 2 people are on the roof at a time • Fewer man hours on the roof • Improved safety with solid working platform and workers tied off No insulation may be required , depending on occupancy. with connected safety lines Frequently Asked Questions: Construction Frequently Asked Questions: Construction

6. Do panelized roofs contribute Yes to a “green” building?

LEED points • MR 5.1&5.2: California has harvesting and manufacturing suppliers within 500 miles of most anywhere. • MR 7: FSC certified OSB available for 1₵ -2₵/sf premium. Sheathing is usually over 50% of total wood cost on a hybrid Energy Efficiency project. • OSB Radiant Barrier Panels • MR 2.1&2.2: Providing recycling bins for wood and steel waste •Block s up to 97 % of r adi an t h eat • EQ4.4: No Urea-formaldehyde is used in OSB and glue • Cost premium ~ $0.05 - $0.10/sf more than traditional OSB laminated timbers made in the US. • Foiled bat insulation cost premium ~ $0.50/sf more than • ID1.1-1.4: LCA analysis will show that wood is the most traditional bat insulation environmentally friendly material

Frequently Asked Questions: Construction Frequently Asked Questions: Construction

7. How does a panelized roof $ contribute to cost savings?

Construction Savings: • Using outlined design methods (sub-diaphragms, suggested connections) saves money on expensive hardware • Ba t i nsu la tion saves $0. 50-$. 75/sf over riidigid Energy Efficiency • Using sloped ledgers instead of crickets at parapet saves on expensive labor • Skylights • Roof penetrations are less expensive to frame and flash ~ 60% • Reduce illumination required savings per penetration • Double glazed skylights provide up to 68% light transmission • Speed of erection = 1/3 less erection time of conventional and all steel w/ 100% transm iss ion • Safer construction methods Cost-Effective Design: Materials Trends Frequently Asked Questions: Construction

• Lower material costs. 7. How does a panelized roof 250 contribute to cost savings? $ 225 200 175 Long Term Savings: Steel • Inexpensive options for energy savings 150 Concrete • Faster construction means the building can be leased sooner 125 CPI 100 $1.25-$1.50/sq.ft. savings, can be realized in a hybrid Wood 75 system when compared to a conventional steel joist 2004 2005 2006 2007 2008 2009 metal deck system

Steel Mill Products Concrete Products Lumber & Plywood Consumer Price Index

Source: U.S. Dept of Labor, Bureau of Labor Statistics

Panelized Floors

. Use your imagination! Have Questions?? Contact WoodWorks

Lisa Podesto 530-520-7966 I lisa@@gwoodworks.org

Archie A. Landreman 262 672-4746 I [email protected]

Tom Milton 763 496-1024 I [email protected]