POST-FRAME BUILDINGS:
A LIGHT-COMMERCIAL
MAINSTAY
Copyright © 2011 National Frame Building Association
CONTINUING EDUCATION
The National Frame Building Association is a Registered
Provider with The American Institute of Architects Continuing
Education Systems.
This program is registered with the 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.
“With so many structural framing options, building
functions, and architectural finishes, post-frame building
systems are limited only by the architect’s imagination and
creativity.”
—Harvey Manbeck, PE PhD, professor emeritus at Penn State
University and NFBA technical advisor
Photo courtesy of Kistler Buildings
Photo courtesy of Wick
“Post-frame contributes very well to both the environment
and the value for your dollar.”
—Cheryl Ciecko, ALA AIA LEED AP CSI GGP, technical director,
WoodWorks, a nonprofit initiative of the Wood Products Council
Photo courtesy of Lester Building Systems, LLC
Photo courtesy of Fingerlakes Construction Company
LEARNING OBJECTIVES
• Versatility and range of
applications
• Structural features that
make these systems
unique
• Key performance characteristics
• Resources for designing post-frame building
systems
Photo courtesy of Morton Buildings
WHAT IS POST FRAME?
Many architects and design professionals are unfamiliar
with post frame.
• It is not commonly included in traditional architectural
school curricula.
• They incorrectly equate post-frame construction with
post-and-beam construction
• They think post frame is only for agricultural buildings
(i.e., barns, storage facilities, or horse facilities).
POST FRAME IS EVERYWHERE
Photo courtesy of Lester Building Systems, LLC
CONVENIENCE STORES
Photo courtesy of Lester Building Systems, LLC
Photo courtesy of Wick Building
Photo courtesy of Fbi Buildings
RESTAURANTS
Photo courtesy of Fbi Buildings
COMMERCIAL OFFICE AND
VETERINARY CLINICS
Photo courtesy of Morton Buildings
Photo courtesy of Morton Buildings
RELIGIOUS SPACES
Photo courtesy of Wick Buildings
PRIVATE HOMES
Photo courtesy of Morton Buildings
PUBLIC BUILDINGS
Photo courtesy of Lester Building
Systems, LLC and SL Construction
Photo courtesy of Morton Buildings
COMMUNITY BUILDINGS
Photo courtesy of Kistler Buildings
Photo courtesy of Little Construction Co., Inc.
RECEPTION HALLS
Photo courtesy of Lester Building Systems, LLC and
Eastern Iowa Building, Inc.
Photo courtesy of Lester Building Systems, LLC and
Eastern Iowa Building, Inc.
RETAIL STORES
Photo courtesy of Lester Building Systems, LLC
POST-AND-BEAM CONSTRUCTION
Pinned
Connection
Girder
(Beam)
Post
Concrete Pier
Continuous Footer
or Pier Foundation
Floor
POST-AND-BEAM CONSTRUCTION
Post
Girder
(Beam)
Purlin
THIS IS POST FRAME
Truss-to-Post Connection
Primary frames
Wood Column
Clear span truss
Embedded Post Foundation
Figure 1. Post-frame building with trusses supported by embedded posts
Roof Purlin
THIS IS POST FRAME
Wall Girt
Figure 2. Post-frame building mounted on a concrete stem wall
PRIMARY FEATURES OF POST
FRAME
Sheathing
Purlins
Truss
Wood
columns
Wall girts
PRIMARY FEATURES OF POST
FRAME
THIS IS POST FRAME—PLAN VIEW
Purlin
Post
Girder (Header)
Clear Span Truss
KEY FEATURES OF POST FRAME
Truss
X-section
Girts
Purlins
Sidewall Post
Post Height
Eave Height
Splashboard
Clear
Span
Post Foundation
Post Footing
KEY FEATURES OF POST FRAME
•
•
•
•
•
wood sidewall columns
wide bay spacing—8 ft and greater
large clear spans—over 100 ft
embedded wood columns or concrete piers
attached wall and roof sheathing or cladding
form structural shearwall/structural diaphragm
system for resisting lateral loads
WOOD SIDEWALL COLUMNS
• Solid-sawn, glued-laminated, or mechanically
(nail) laminated wood
• Nominal 6x6, 6x8, 8x8, or 8x10 cross section
• Typically spaced 4, 6, 8, 12, or 16 ft on center
along sidewall
• Any portion of the wood post embedded directly
into the ground and 6–12 in. above grade is
pressure preservative treated to AWPArecommended levels for ground contact
WOOD SIDEWALL COLUMN
Spliced glued-laminated
column
• 3- or 4-ply, fabricated
with 2x lumber
• lower portion is
preservative treated
• upper portion is
untreated
WOOD SIDEWALL COLUMNS
Nail-laminated
posts with treated
bottom spliced to
untreated top
Preservativetreated splash
board
WOOD SIDEWALL COLUMNS
Untreated Post
Concrete Pier
PRESSURE PRESERVATIVE
TREATMENTS
• Posts embedded in
the ground, specify:
• use category UC4B
or better per AWPAU1-09
• e.g., CCA@0.60 pcf
POST FOUNDATION OPTIONS:
EMBEDDED TREATED COLUMNS
Treated
PRECAST OR CAST-IN-PLACE
REINFORCED CONCRETE PIER
• Pre-cast reinforced concrete
pier with post attached
above grade
• Entire assembly preengineered
• Assembly usually fabricated
in factory and shipped to
site as a single unit
PRE-CAST REINFORCED CONCRETE
PIER
Reinforcement
Cleat
Cast-in-Place
Concrete
Foundation Wall
CAST-IN-PLACE CONCRETE
FOUNDATION WALL
Untreated Post
Connection
Hardware
THICKENED CONCRETE SLAB
THICKENED CONCRETE SLAB
PROTECTIVE POST COVERS
• Blow-molded plastic or HDPE
plastic protective barriers
• Provide moisture and insect
protection
• “Enhance protection of copperbased chemical treated wood
posts or laminated columns”
ROOF FRAMING
• Pre-engineered metal plate connected 2x lumber
trusses typically spaced 4–8 ft on center
• Heavier timber trusses for larger post and truss
spacings and aesthetic requirements
• Solid-sawn wood rafters spaced 2–4 ft on center
for shorter clear spans
• Glulam rafters for larger rafter spacings or clear
spans
ROOF FRAMING
Trusses
Sidewall
Post
(connected
to trusses)
POST TO ROOF FRAMING
CONNECTIONS
• Posts are connected directly to the roof framing if
post and roof framing spacing are the same
• Posts and roof framing are often connected to
header beams if post and roof framing spacing
are not the same
POST TO ROOF FRAMING
CONNECTION
Block
Height
Block
Connection is usually a pinned connection (not a moment-resisting connection).
POST TO ROOF FRAMING
CONNECTION
POST TO ROOF FRAMING
CONNECTION
SOLID SAWN POSTS
Typical post to truss connection details for a
solid sawn post application
Connection with
truss fastened to
slide of post and
with bear block
1½”
Connection
with truss
bearing on
notch in post
POST TO ROOF FRAMING
CONNECTION
• Schematic of typical
connection details
• Truss to header
(girder)
• Header (girder) to roof
POST TO ROOF FRAMING
CONNECTION
Metal Plate
Connector
Header
(Girder)
Blocking
ROOF PURLIN PLACEMENT
Purlins oriented flat
or “on edge,”
depending on truss
and purlin spacing
Purlins placed either
on top or inset
between truss top
chords or inset
between roof rafters
ROOF FRAMING AND PURLINS
Purlin
2 ft o.c.
8 ft o.c.
Connection to
Post Connection
Truss
WALL GIRTS
• Typically 2x4 to 2x8 solid sawn lumber, spaced
24–32 in. apart
• Oriented “flat” on outside face of wall post for
smaller post and girt spacings and loads
• “On edge” between adjacent posts for larger
loads or post or girt spacings
WALL GIRTS AND SHEATHING
Wall Girt
Sheating
WALL GIRTS AND SHEATHING
SECONDARY FRAMING AND
BRACING
•
•
•
•
•
Corner bracing in upper chords of trusses
Diagonal bracing for lower chords of trusses
Lower chord stiffeners for trusses
Cross bracing of selected compression webs
Continuous longitudinal bracing of long
compression webs and chords of trusses
TRUSS BRACING
• Guide to Good Practices for Handling, Installing,
Restraining & Bracing of Metal-Plate Connected
Wood Trusses (WTCA and TPI)
• B1 and B3 summary sheets: handling and
bracing trusses
• B10 summary sheet: Post-frame truss
installation and bracing
UNIQUE FEATURES OF PF
The most economical combination has
• laminated wood sidewall and endwall columns
• embedded post or embedded concrete pier
foundations
• metal-plate connected 2x wood roof trusses and
• 26- to 29-gauge ribbed steel roof and wall
sheathing
PF TECHNICAL RESOURCES
• ANSI/ASAE (ASABE) EP 484 for diaphragm
design of metal-clad, post-frame rectangular
buildings
• ANSI/ASAE (ASABE) EP 486 for shallow post
foundation design
• ANSI/ASAE (ASABE) EP 559 for design
requirements and bending properties for
mechanically laminated columns
PF BUILDING DESIGN MANUAL
• Structural design procedures
for PF building systems
– PF designer’s primary
reference
– www.NFBA.org
BENEFITS OF POST FRAME
•
•
•
•
•
•
Cost-effective
Energy efficient
Code compliance
Sustainability and greenness
Design flexibility
Durability and strength
MORE ABOUT POST FRAME
• National Frame Building
Association (NFBA)
• www.PostFrameAdvantage.com
• www.NFBA.org
• NFBA
4700 W Lake Ave
Glenview, IL 60025
QUESTIONS AND COMMENTS?
• National Frame Building
Association (NFBA)
• www.NFBA.org
• www.PostFrameAdvantage.com
• NFBA
4700 W Lake Ave
Glenview, IL 60025
PREPARED BY
HARVEY B. MANBECK, P.E., PHD
PROFESSOR EMERITUS PENN STATE UNIVERSITY
COPYRIGHT @ 2011 BY
THE NATIONAL FRAME BUILDING ASSOCIATION