An engineer has liberty to include whatever he deems necessary to convey the results of his structural calculations in a building blueprint. However, there is a minimum amount of information that should be included in a structural plan. Many states have minimum requirements for structural plans. The Pennsylvania Uniform Construction Code provides a “UCC Plan Review Checklist” Form UCC-2. This checklist includes a section referring to structural plans with 19 items to be included, if applicable, in a structural plan. Other states have similar checklists included in their state building codes.
In addition to including this minimum information in a structural plan, Table 1 is a sample outline of post-frame building design data that may assist post-frame engineers.
Table 1. Suggested Outline for Gathering Post-Frame Building Design Data
I. Structural Loading
A. Determine Governing Code: IBC 2003, ASCE 7, etc.
1. Use Group Classification
2. Type of Construction
B. Dead Loads:
1. Roof ___ psf
2. Floor ___ psf
3. Other ___ psf
C. Live Loads:
1. Roof (see also Snow Loads) ___ psf
2. Floor ___ psf
3. Other ___ psf
D. Truss Loads:
1. Top Chord Live ___ psf
2. Top Chord Dead ___ psf
3. Bottom Chord Live ___ psf
4. Bottom Chord Dead ___ psf
E. Snow Loads:
1. Ground Snow (Pg) ___ psf
2. Flat Roof Snow (Pf) ___ psf
3. Snow Exposure Factor (Ce) ___ psf
4. Snow Load Importance Factor (I) ___ psf
5. Unbalanced Snow
a) Windward roof ___ psf
b) Leeward roof ___ psf
F. Wind Load
1. Basic Wind Speed (V) ___ mph
2. Wind Load Importance Factor (I) ___
3. Wind Exposure Category ___
G. Equipment Load:
1. Fire Suppression Systems
2. Lights, Heaters, HVAC units
H. Stored Material Loads:
1. Equivalent Fluid Density (EFD) ___ pcf
I. Earthquake Design Data:
(analysis based on equivalent lateral force procedure)
1. Spectral Response Acceleration at 1 sec, S
2. Spectral Response Acceleration at short periods, S
J. Seismic Use Group
1. Occupancy Importance Factor, I
2. Site Class
K. Basic Structural System
1. Light Framed Walls with Shear Panels
2. Response Modification Factor (R)
3. Deflection Amplification Factor (Cd)
L. Structural Calculations
1. Loads and Load Combinations Used
2. Load Paths Used to Resist Forces from Applied Loads and/or
Load Combinations
3. Methodology Used to Determine Adequacy of the Components Specified
4. Stiffness of Components and Systems
5. Main Frame Member Design
a) Truss
b) Posts
c) Foundations
d) Diaphragm
e) Connections
6. Secondary Member Design
a) Girts
b) Purlins
c) Connections
d) Sheathing Loaded Perpendicular to Plane
7. Bracing
a) Load that the Brace will Carry
b) Load Path for the Brace System
c) Stability of the Bracing Components
M. Structural Analysis for Other Items
1. Floor System Design
2. Window and Door Framing
3. Large Door Headers
4. Roof, Wall, and Ceiling Coverings
(If they are part of the diaphragm system or transfer-applied load
to the secondary or main framing)
II. Footings
A. Compaction & Leveling of Footing Sub Grade after Footing Holes
are Augured
B. Type of Concrete to Use based on Structural Load Application
& Current Temperature.
C. Slump
D. PSI
E. Mixture
F. Size, based on:
1. Soil Bearing Capacity
2. Applied Building Live Loads
3. Applied Building Dead Loads
G. Depth
1. Embedment
2. Below Frost Line
3. Building Height
H. Re-Rod Mat Reinforcement
(typically used to reduce the thickness of the footing)
1. Size
2. Grade
3. Placement of Rod
4. Field Ability to Place Mat at the Proper Location
III. Columns*
A. Spacing -
Examples: 8’, 9’, 10’, 12’
B. Type of Column -
Examples: Solid Sawn, Nail Laminated, Glue Laminated, Nail & Glue
Laminated, Concrete Base
C. Size -
Examples: 4x6, 6x6, 3-ply 2x6, 4-ply 2x6, 3-ply 2x8, 4-ply 2x8
D. Species & Grade of Lumber -
Examples: SYP, MSR, #1, #2, Select Structural
E. Treatment Levels -
Examples: .40 Pcf, .60 Pcf, .80 Pcf
F. Treatment Use Group -
Examples: Ground Contact (4A), Fresh Water/Ground Embedment (4B),
Permanent Wood Foundation/Severe Environments (4C)
G. Type of Treatment -
Examples: ACQ, Copper Azole, CCA
H. Length of Treatment -
Examples: for Laminated Columns, 6’, 7’ or Full Column Treatment
I. Fabrication Requirements, for Field-Fabricated Columns
1. Fastener Type
2. Fastener Size
3. Fastener Spacing
J. Column Uplift Anchors -
Examples: Treated Blocks, Tie Clips to Footings, etc.
K. Column Embedment -
Examples: 4’ Deep, 5’ Deep
*Design Note: Not all solid-sawn and laminated columns are equal to
each other
IV. Wall Girts
A. Size -
Examples: 2x4, 2x6, 2x8
B. Spacing -
Examples: 16”, 24”, 36”
C. Species & Grade -
Examples: #2 Spruce Pine Fir, #2 Southern Yellow Pine
D. Connection Requirements
1. Nails
a) Size -
Example: Shank Diameter and Length
b) Type -
Examples: Ring Shank, Spiral Shank, Common
c) Quantity & Location
d) Coating - Approved Hot-Dipped Galvanized or Stainless Steel
(if in treated wood)
V. Supports (Truss Carriers)
A. Size -
Examples: 2x6, 2x8, 2x10, 2x12, LVL
B. Species & Grade -
Examples: Select Structural Hem Fir, #1 Southern Yellow Pine
C. Quantity -
Examples: 2, 3, 4, 5, 6 Members
D. Connection Requirements of Members
(connection to column, connection to each other)
1. Nails
a) Size -
Example: Shank Diameter and Length
b) Type -
Examples: Ring Shank, Spiral Shank
c) Quantity & Location
d) Coating - Approved Hot-Dipped Galvanized or Stainless Steel
(if in treated wood)
2. Bolts
a) Size
b) Hardness
c) Quantity & Location
d) Coating - Approved Hot-Dipped Galvanized or Stainless Steel
(if in treated wood)
e) Note: Not all the Same Size Dimensional Lumber is Equal
(1) Base Design Value for 2x12 #2 Doug Fir Larch - Fb=900
(2) Base Design Value for 2x12 Select Structural Hem Fir - Fb=1400
Fb = Allowable Extreme Fiber Stress in Bending
Source: Western Lumber Product Use Manual 5-01
The fiber stress values, along with other design values,
are used to determine what the 2x12 will support.
VI. Bearing Blocks
A. Used for Additional Connection Fasteners when there is Not Enough Space
in the Supports (Truss Carriers) for the Total Number of Required Fasteners
B. Blocks, Width of Column, Placed Below Supports
(truss carriers)
C. Species and Grade Requirements
D. Length Requirements of Bearing Block
E. Connection Requirements
1. Quantity of Fasteners
2. Type of Fasteners
VII. Roof Trusses
A. Loads
1. Top Chord Live Load
(Snow)
a) Formula from ASCE 7 to Determine Top Chord Live Load
(1) Pf=0.7CeCtIPg
(2) Ce=Exposure Factor
(3) Ct=Thermal Factor
(4) I=Importance Factor
(5) Pg=Ground Snow
b) Slope Factor (Cs)
c) Unbalanced Loads
(windward, leeward)
d) Step Roof Condition
(if applicable)
e) Top Chord Pitch -
Examples: 4/12, 5/12, etc.
2. Top Chord Dead Load
a) Roofing Material
b) Roof Top Equipment
3. Bottom Chord Live Load
a) Attic Storage Loads, if applicable
4. Bottom Chord Dead Load
a) Ceiling material
b) Lights
c) Mechanical Equipment
d) Ceiling Insulation
B. Additional Design Factors & Loads
1. Centers -
Examples: 2’, 4’, 8, etc.
2. Bearing Width at Heel
3. Bottom Chord & Web Lateral Bracing Location
(provided by truss fabricator)
C. Permanent Truss Bracing & Connections
(designed by building designer)
1. Truss X-Bracing
2. Wind Bracing
3. Connection Requirements of Bracing
(by building designer)
4. Truss Connection Requirements for Uplift
(truss print will show uplift reactions)
a) Anchored to Column, Direct Bearing on Column at Bearing Wall
b) Anchored to Truss Supports (Carriers) by Using:
(1) Tie Down Blocks
(2) Steel Anchor Clips
(3) Steel Straps
c) Bolts & Nails
(1) Type –
Examples: Hardened Bolts, Ring Shank or Spiral Shank Nails
(2) Size of Fasteners
(3) Quantity of Fasteners
D. Equipment Loads
1. Concentrated Loads on Top or Bottom Chords
2. Location of Equipment Loads
E. Transferring Loads
1. Transferring the Roof Loads & the Equipment Loads:
a) To the Truss Supports
(Carriers)
b) To the Columns
c) To the Footings
d) To the Connections & Fasteners of Each Component
VIII. Roof Purlins (if required)
A. Size of Material -
Examples: 2x4, 2x6, 2x8
B. Spacing -
Examples: 16”,19.2”, 24”
1. Configuration
2. Flat
3. On Edge
4. In Hangers
(Note: If hangers are required, specify type of hanger)
C. Species & Grade -
Examples: #2 Spruce Pine Fir, #1 Southern Yellow Pine
D. Connection Requirements
1. Size -
Examples: Shank Diameter and Length
2. Type -
Examples: Ring Shank, Spiral Shank
3. Quantity & Location
4. Fasteners Required for Hangers
IX. Permanent Building Bracing
A. Wall Bracing
1. Corner
2. Mid-Point
(depending on building length, may require additional sets of bracing)
B. Roof Bracing
(coordinate with truss design)
1. End
2. Mid-Point
(depending on building length, may require additional sets of bracing)
C. Material
1. Pre-Punched Galvanized Steel Banding
2. Dimensional Lumber
D. Connection Requirements
1. Size -
Examples: 10d, 16d
2. Type -
Examples: Ring Shank, Spiral Shank
3. Quantity & Location
4. Fasteners Required for Pre-Punched Galvanized Steel Banding
E. Diaphragm Design
1. Exterior Walls & Roof
2. Wood Structural Panel Sheathing, Metal Panels
3. Fastener Requirements
X. Door Headers
A. Bearing Wall Headers
1. Glue-Laminated Beams
2. Stack Dimensional Lumber
3. LVL
(Laminated Veneer Lumber)
4. Size, Species & Grade of Material
5. Connection & Fastener Requirements
a) To Columns
b) Field-Fabricated, Stacked Dimensional Material
B. Non-Bearing Wall Headers
1. Dimensional Lumber
a) Size -
Examples: 2x6, 2x8, 2x10, 2x12
b) Species & Grade of Material
c) Connection & Fastener Requirements
XI. Door Framing
A. Overhead & Track (Slider) Doors
1. Side Jambs, Back Jambs
2. Using Jambs as a Bearing Member
of Door Header (if applicable)
B. Walk Doors
1. Vertical Framing
2. Column
3. Header
C. Above Components
1. Size, Species & Grade of Material
2. Connection & Fastener Requirements
XII. Window Framing
A. Framing Requirements
1. Headers, Sills, Jambs
2. Size, Species & Grade of Material
B. Connection & Fastener Requirements
C. Elevation of Windows
D. Transition Requirements from Siding to Window
XIII. Walk Doors
A. Manufacture or Equal
B. Size -
Examples: 30/68, 60/68
C. Type -
Examples: Economy, Thermo Break, Heavy Duty, Fire Rated
D. Hardware Set
1. Locksets
2. Closers
3. Dead Bolts
4. Kick Plates
5. Panic Bars
6. Etc.
E. Door Windows -
Examples: Half, Full, 9-Lite, Narrow
XIV. Siding (Exterior Finish)
A. Steel
(Metal Panel)
B. Manufacturer
C. Panel Profile
D. Gauge
E. Yield Strength, Ultimate Strength, or Both
F. Paint System
G. Trims
1. Hemmed, Exposed Edges
2. Soffit-Vented or Smooth, Aluminum or Steel
H. Other Options
1. Brick Wainscot
2. EFIS
3. Wood
4. Vinyl Siding
5. Many more
I. Connection & Fastener Requirements of Siding Components
(usually provided by siding manufacturer)
J. Barrier between Metal Panel Siding and Treated Framing Components
(Examples: Ice & Water Shield, Vycor Plus, Vycor Deck Protector)
XV. Roofing
A. Steel (Metal Panel)
B. Manufacture
C. Panel Profile
D. Gauge
E. Yield Strength, Ultimate Strength, or Both
F. Paint System
G. Trims
1. Hemmed Exposed Edges
2. Soffit-Vented or Smooth, Aluminum or Steel
H. Shingles
1. Manufacturer
2. Shingle Model -
Examples: 3-in-1, Architectural
I. Underlayment -
Examples: 15# Felt, 30# Felt, Roofers Select, Ice & Water Shield
J. Roof Decking -
Examples: OSB, Plywood, Insulated Structural Panel
1. Thickness-1/2”, 5/8”, ¾”, etc.
K. Spacer Clips (if required)
L. Connection & Fastener Requirements of Roofing Components
(usually provided by material manufacturer)
XVI. Concrete Floor
A. Mix Specifications
B. Slump
C. Thickness
D. Air Entrained
E. Reinforcement
(welded wire, fiber mesh, etc.)
F. Rodent Walls
(depth & thickness)
G. Thresholds, if applicable
(pipe for overhead & angle for slider doors)
H. Sealers & Curing Compounds
I. Control & Expansion Joints
J. Door Apron
1. Size
2. Thickness
3. Thickened Edges
XVII. Other Items to Consider in the Building Design:
A. Interior Partition Walls, Framing, Insulation, Wall Finish
B. Interior Doors, Size, Type (Fire & Finish), Swings, Hardware, etc.
C. Equipment & Fixture Blocking
D. Interior Windows, Size, Type of Glass, etc.
E. Interior Furnishings, Cabinets, etc.
F. Fire-Rated Assemblies for Walls & Ceilings
(as required)
G. Temporary Construction Bracing
XVIII. For All Framing Members
A. Determine Size and Quantity of Nails Based on Species of Lumber and
Reaction Loads that Each Nail Must Support
B. Placement of Fasteners
The outline in Table 1 represents only an example of the information to be included in an engineer’s plans and specifications prior to certifying a plan. The outline is not intended to be a definitive and prescriptive requirement for design, but a guideline for making designs and specifications that are as complete and accurate as possible. Each structural engineer must decide what information will be included in plans and specifications prior to applying a seal. There are many design standards and tools available that apply to structural engineering in general and for specific use with post-frame building design.
Post-frame buildings are complex three dimensional (plane frames and diaphragms perpendicular to the plane frame) structures requiring in depth structural analysis that relies on competent engineering. Proper and complete structural analysis will provide the information required for the “Suggested Outline for Gathering Post-Frame Building Design Data” given in Table 1.
A complete building design also will often require engineering calculations other than structural ones. The thermal insulation, ventilation, heating/cooling, moisture removal (vapor barriers and drain paths), electrical, and plumbing systems all will impact functionality of the building. These systems may require that the design engineer(s) ensure that differently-designed systems do not compromise one another. For instance, some types of roof insulation may maintain the thermal integrity of the roof system, but detract from the strength and stiffness of the roof diaphragm.
Table 1, “Suggested Outline for Gathering Post-Frame Building Design Data,” is not intended as an infallible or exhaustive list of requirements for all post-frame designs. The ingenuity and creativity of design professionals today and in the future will cause incessant evolution of engineering practices. The performance-oriented design process allows post-frame to be competitive and even preferred over other types of construction that tend to be prescriptive in nature. Engineers should remain free to develop new ways to solve problems (designs), and to use analysis tools that show that the solution created is sound from both a scientific and engineering perspective. The table is only intended to provide ideas for engineers to consider when approaching post-frame design. Therefore, the table should not be construed by any party to be a prescriptive pronouncement of an approval process or mandatory requirements for engineering any post-frame building.
In order to ensure “advancement and betterment of human welfare” we must ALL insist that complete engineering be performed prior to providing professional certification for any project. While every item on the sample outline in Table 1 may not apply to each specific project and some projects will require engineering not listed, ALL projects require the highest level of professional conduct from both engineers and builders alike.
Tim Royer is President of Timber Tech Engineering, Inc., and serves on the NFBA Editorial Review Committee. Special recognition goes to Doug Thomsen for his work on Table 1, “Suggested Outline for Gathering Post-Frame Building Design Data.” This article originally appeared in the June 2006 issue of NFBA’s official post-frame industry publication, Frame Building News magazine. To start your free subscription to Frame Building News, visit www.framebuildingnews.com.
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NOTE: A model guide specification in three-part format has been developed by NFBA. Click here for more information about the specification, and the new online Post-Frame Design Specification Generator.
