Dalton Panelized Roofs

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All-Wood and Hybrid Panelized Roof

Structure Systems

Cost Effective Roof Solutions

• “The Wood Products Council” is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.

This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

• Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

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Learning Objectives:

• Gain the ability to decide which panelized roof system best

suits your building’s needs

• Understand the basic structural, fire protection and

construction aspects of designing and constructing a

panelized roof.

• Learn what resources can help a designer design a high load

diaphragm

• Learn what makes a panelized roof system so cost effective

At the end of this program, participants will be able to know:

What is a panelized roof?

�History

�Structural Components

�Construction/Erection methods

Learning Objective #1 What is a Panelized Roof?� Pre-fabricated roof sections

lifted into place

� Safety, cost, speed

� Two common types

� All wood

� Hybrid

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Evolution of Panelized Roof Construction

Over 40 years ago, a small

California company called

Berkeley Plywood, began with a

revolutionary new method for

framing a roof on industrial and

commercial buildings.

Originally called the Berkeley

Panelized System, this method

of framing became the mainstay

for large wood roof structures

throughout the West Coast

Progression From Plywood to

OSB (Oriented Strand Board)Pre-1980s:� Only CDX or S-1, 5-ply plywood was used� “Wafer” board was used in some residential applications

1980s:� American Plywood Association (APA) brought credibility to the

product� New panel performance standards issued� Building codes in US & Canada accept OSB for same uses as

plywood on a thickness-by-thickness basis – “Structural Use Panels”

Conversion to ‘Hybrid’ Panelized Roofs

1990:

� Spotted Owl & other factors drive the cost off ‘all wood’ systems to an all time high.

� The ‘Hybrid’ panelized roof system is introduced by Panelized Structures, Inc. and Vulcraft steel joists.

� In addition to huge cost savings, the use of open-web steel joists & girders resulted in large bay spacing – 60’ purlin spans & 52’ girder spans became typical.

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Since 1991, Many National

Companies Have Preferred

the “Hybrid” Roof Structure

Out West

Defining Panelized System Elements

Subpurlin / Stiffner

Wood Structural Panel Sheathing

Purlin

Pre-framed Panel


Purlin

Pre-framed PanelPurlin

� 2½” Glulam, I-joist, Open-web truss

� Open-web steel joist

� Stiffeners attached with joist hangers


Sub purlin / Stiffener

Pre-framed Panel

Sub purlin / Stiffener� 3x6/2x6 lumber

� Spaced at 24” oc

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� 4x8, 4x10, or 8x8 jumbo panels

� OSB or plywood

APA Sheathing

Pre-framed Panel

APA Sheathing

Jumbo panel


� Simple span glulam (or Cantilevered Glulam)

� Open-web steel joist

� Pre-framed panel spans between girder lines

GirderGirder

Pre-framedpanel

• All Wood Panelized Roof – Sub-purlins and purlins are wood elements

– Girders are solid or engineered wood

– Decking is always wood structural panel

� Glulam Purlin

� I-Joist Purlin� Open Web Wood Truss Purlin

� Cantilevered Span Glulam

� Balanced layup

� 24F-V8/ 24F-1.8E

� Simple Span Glulam

� Unbalanced layup

� 24F-V4/ 24F-1.8E

Girder Spans

• High Strength Composite (HSC) Glulam

– LVL tension laminations

– No finger joints

– 30F – 32F

– ~20% cost premium

Terminology: Hybrid

� Hybrid Panelized Roof� Purlins and girders are steel

� Sub-purlins are often wood

� Decking is always wood structural

panel

� K-Series**

� Short span

� Ex: 20K5 or 20K240/128

� LH-Series**

� Long span

� Ex: 32LH10 or 32LH310/160

� G-Series**

� Girders

**Steel Joist Institute Specifications

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The Panelized Process

Tilt and brace walls Joists arrive with

nailers attached

OSB and all materials are

delivered inside building

Tie-joists are set per OSHA Sub-purlins are ‘hangered’

with ‘F’ hangers

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What are structural advantages of the panelized roof?� Seismic resistance

� Wind resistance

� Fire Protection

� Ease of Design

Learning Objective #2

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Panelized Wood Roofs Provide

Enhanced Structural Performance

� These wood roof diaphragms can resist 1800 plfshear loads as shown in IBC Table 2306.2.1

Seismic Resistance

Seismic Resistance

Braced Frames

� Interior shear resistance

can be provided with

Brace Frames

� 1/2” JUMBO equals value of 5/8” standard 4x8 panels

� Strength axis installed perpendicular to supports resulting in superior bending values

High FM Wind uplift rating

A 135 mph FM rated wind up lift rating has been assign to the panelized wood roof system.

Figure 10 illustrates a panelized roof system that meets the panel attachment requirements for the various FM Windstorm Classifications.

The Panelized Wood Roof System and

Fire - Wind - Insurance

The panelized w ood roof system performs just as well as the conventional “metal deck” system for buildings with use and occupancy classifications B,F,M or S

• The panelized w ood roof system is just as “Fire-Proof” as the metal deck system when ESFR sprinklers are used - From the FM Data sheet 2-2:

• 3.1 Loss History -There are a total of six known fires involving suppression mode sprinkler protection. In all of these incidents, suppression mode protection was successful and no more than four sprinklers operated. In the two incidents for which detailed information was available, the sprinklers involved were not obstructed.

• The Panelized Wood roof system is “FM insurable”

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Heights & Areas of Type V-b

Buildings with Wood Roofs

Allowable Area

IBC Section 507.3 permits the area of a one-story, Group B, F, M or S building to not be

limited when the building is provided with an automatic sprinkler system throughout in

accordance with Section 903.3.1.1 (NFPA 13) and is surrounded and adjoined by public

ways or yards not less than 60 feet in width.

Allowable Heights

Table 503 shows 40’ max for Type V-b bldgs. + 20’ for sprinklers per 504.

504.2 Automatic sprinkler system increase. Where a building

is equipped throughout with an approved automatic sprinkler

system in accordance with Section 903.3.1.1, the value

specified in Table 503 for maximum height is increased by 20

feet (6096 mm) and the maximum number of stories is

increased by one.

One Story Buildings with All-wood or Hybrid Roofs can

have heights up to 60’ and the area is unlimited

No Structural Expansion Joints (DBL Frame Lines)

Are Required

Design Assistance http://www.apawood.org

http://www.woodworks.org

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Learning Objective #3

Other favorable characteristics of the panelized roof?� Durability

� Environmental benefits

� Cost effectiveness:

� Structure cost

� Roofing & insulation,

� Schedule

� Safety

Norwegian Stave Churches

Urnes Stave Church (c. 1150)

Borgund Stave Church (c. 1180)

Built in 12th & 13th centuries …25-30 still remain today

DurabilityBuildings erected in the 50s are still functional today!Still solid and working as designed for over 50 years!

Carbon is Stored

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Comparing CO2 emissions of

different materials

Sawn lumber

products have a

negative net CO2

contribution

Wood industry

often contributes

biomass energy to

the grid

The Wood Roof Structures are

Green• lumber comes from managed forests, where companies are

planting more trees than they are harvesting.

• OSB is produced from faster growing northern species, not old growth coastal, making good use of the forest resource.

• OSB manufacturers have replanted more that 22 million trees.

• Steel open-web trusses are made from recycled steel.

OSB Roof with Factory Applied Radiant Barrier

With White-Faced Batt Insulation

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Value

It makes dollar sense!

Speed of Erection

The fast erection process cuts construction times - a typical 100,000 square foot warehouse roof takes approximately 2-3 weeks to erect

Floor space free of construction prefab debris during erection

process and sub trades can move in quickly

No expansion jointsRoof membrane can be attached directly to sheathing using a thin DensDeck or

similar protective sheet.

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$1.00 - $3.50 per sq.ft. savings can be realized in a hybrid system when compared to a conventional steel joist metal deck system

Long Term Savings:

• Inexpensive options for energy savings

• Faster construction means the building can be leased sooner

Comparative cost savings

$

Safe erection methods

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Learning Objectives #4

Where can the system be used?

�Industrial Bldgs.

�Warehousing

�Manufacturing

�Light Commercial

�Retail

�Sport Facilities

�Specialty

Where are Panelized Roofs used?

Designed by Kramer and Lawson

� Most commonly with

tilt-up concrete or

masonry walls

� Typical for large, low

slope, roof structures


Designed by Structural Design Group


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Panelized Roofs

Questions?

This concludes The American Institute of Architects

Continuing Education Systems Course

Mark A. Dalton, SESenior Technical Director – Central US

WoodWorks for Non-Residential Construction

Tel: [email protected]

www.woodworks.org

Documents

Dalton Panelized Roofs