What Is Covered?
Ordering a metal building involves more than selecting its width, length, roof style, colors, doors, and optional lean-tos. Before a building can be manufactured and installed, the buyer may also need documentation showing that the structure has been designed for the applicable snow, wind, and structural loads.
Depending on the building’s location, dimensions, openings, intended use, and configuration, it may qualify for engineered stamped generic drawings. Buildings that fall outside the approved generic parameters may instead require site-specific engineered drawings.
At Metal Carports and Buildings, we help customers compare their proposed building against the available engineering limits before the order is finalized. Understanding these limits early can help prevent redesigns, additional engineering expenses, and delays during the permitting process.
“Engineering should never be treated as an afterthought. We want to identify the building dimensions, openings, local loads, and intended use before the customer places the order. That gives everyone a clearer path forward and reduces the chance of expensive changes later.”
— Mike Daniels, Owner, Metal Carports and Buildings
This guide explains what engineered stamped generic drawings generally cover in Utah, Idaho, Wyoming, Montana, Washington, Oregon, Colorado, New Mexico, Oklahoma, Kansas, Nebraska, and Texas.
What Are Engineered Stamped Generic Drawings?
Engineered stamped generic drawings are structural plans prepared and stamped by a licensed professional engineer for a defined range of metal-building configurations. Unlike site-specific plans, generic drawings are not created exclusively for one address or one customer. They apply when the ordered structure remains within the dimensions, loads, openings, roof pitches, lean-to configurations, anchoring details, and other limitations contained in the approved drawing package.
These drawings may include structural details for the building’s framing system, trusses, roof members, wall members, connections, bracing, anchors, frame spacing, material specifications, maximum dimensions, and allowable openings. The drawings may also identify the design criteria under which the structure was evaluated.
The American Society of Civil Engineers explains that ASCE 7 is the nationally adopted loading standard used to address hazards including snow, wind, seismic forces, rain, flooding, soil loads, and other structural design conditions. That is important because the correct engineering for a metal building is determined by much more than its overall size.
Generic drawings can be efficient when a proposed structure fits within their approved parameters. However, they should not be interpreted as universal plans that automatically apply to every building, property, or jurisdiction.
Why Generic Engineering Has Defined Limits
A generic engineering package is based on a predetermined set of structural assumptions. Those assumptions may include the maximum building width and height, roof pitch, snow load, wind exposure, frame spacing, bracing arrangement, number of enclosed walls, opening sizes, lean-to dimensions, and anchoring method.
Changing one of those variables can affect the forces transferred through the entire structure. For example, increasing the width of a garage-door opening may change the amount of framing and bracing needed around that opening. Increasing the height may increase wind pressures and overturning forces. Adding a lean-to may introduce additional snow, uplift, drainage, and connection loads.
Metal building systems are not merely collections of interchangeable parts. The International Building Code describes a metal building system as an integrated group of fabricated components and assemblies forming a complete or partial building shell. Current structural guidance emphasizes that these optimized systems depend heavily on their connections and bracing components to perform as designed.
“Metal building systems are extremely efficient, but that efficiency depends on the components working together as one engineered system. Width, height, openings, bracing, roof configuration, anchors, and local loads all matter.”
— Mike Daniels, Owner, Metal Carports and Buildings
Generic Drawing Coverage for Colorado, Idaho, Wyoming, Texas, Nebraska, New Mexico, Oklahoma, and Kansas
For buildings located in Colorado, Idaho, Wyoming, Texas, Nebraska, New Mexico, Oklahoma, and Kansas, the applicable engineered stamped generic drawings generally cover buildings up to 30 feet wide and 16 feet tall.
Side openings and end openings must not be wider than 16 feet. This limitation is especially important for customers considering large garage doors, open equipment bays, RV entrances, or drive-through configurations. An opening that exceeds the generic limit may require a different building layout or site-specific engineering.
Side and end lean-tos may be covered when each lean-to is no wider than 12 feet and its outside leg is no higher than 12 feet. Roof pitches up to 6:12 may be covered.
These generic drawings do not cover standalone lean-tos or loafing sheds. A standalone lean-to is structurally different from a lean-to attached to an engineered primary building because it lacks the same central building frame and connection conditions assumed in the generic package.
General limits for these states
- Maximum building width: 30 feet
- Maximum building height: 16 feet
- Maximum side opening: 16 feet
- Maximum end opening: 16 feet
- Maximum lean-to width: 12 feet
- Maximum lean-to outside-leg height: 12 feet
- Maximum roof pitch: 6:12
- Standalone lean-tos: Not covered
- Loafing sheds: Not covered
Generic Drawing Coverage for Utah, Washington, Oregon, and Montana
For buildings located in Utah, Washington, Oregon, and Montana, the engineered stamped generic drawings generally cover buildings up to 30 feet wide and 16 feet tall.
Openings may be as wide as 20 feet on either the side or end of the building. This provides additional flexibility for larger garage doors, agricultural equipment access, RV entrances, and open bays, provided the remainder of the building remains within the applicable design limits.
Side and end lean-tos may be covered when they are no wider than 15 feet and the outside leg is no higher than 14 feet. Roof pitches up to 6:12 may also be covered.
As with the other state-specific generic packages, standalone lean-tos and loafing sheds are not included.
General limits for these states
- Maximum building width: 30 feet
- Maximum building height: 16 feet
- Maximum side opening: 20 feet
- Maximum end opening: 20 feet
- Maximum lean-to width: 15 feet
- Maximum lean-to outside-leg height: 14 feet
- Maximum roof pitch: 6:12
- Standalone lean-tos: Not covered
- Loafing sheds: Not covered
A&A Generic Drawings Should Be Used First When Applicable
When a proposed structure qualifies under the A&A generic engineering parameters, those drawings should generally be used first.
A&A generic drawings typically cover buildings up to 30 feet wide and 12 feet tall. Side openings may be up to 12 feet wide, while end openings may be up to 14 feet wide.
Lean-tos may be covered when they are no wider than 12 feet and the outside leg is no higher than 19 feet. Roof pitches up to 4:12 may be included.
A&A generic drawings do not cover standalone lean-tos, loafing sheds, or drop-down lean-tos.
General A&A limits
- Maximum building width: 30 feet
- Maximum building height: 12 feet
- Maximum side opening: 12 feet
- Maximum end opening: 14 feet
- Maximum lean-to width: 12 feet
- Maximum lean-to outside-leg height: 19 feet
- Maximum roof pitch: 4:12
- Standalone lean-tos: Not covered
- Loafing sheds: Not covered
- Drop-down lean-tos: Not covered
The A&A limits should be evaluated before assuming that a broader or more expensive engineering option is necessary. However, the actual building configuration must match the drawings. A customer should not order a building based solely on one measurement while overlooking other limits involving openings, lean-tos, roof pitch, use, or local design loads.
Snow-Load Coverage for Generic Metal Building Drawings
Generic drawings generally cover ground snow loads of up to 90 pounds per square foot, subject to the design and limitations contained in the applicable plans.
Open buildings are different. Open carports, RV covers, equipment covers, and partially enclosed buildings may be limited to approximately 80 pounds of ground snow load or less. The engineering department should confirm the exact limit because it may vary based on the building’s width, height, roof pitch, frame spacing, exposure, bracing, and number of open walls.
Ground snow load should not automatically be treated as the same value as roof snow load. Engineers use the applicable code provisions and site conditions to convert ground snow information into the design loads applied to the building. ASCE 7 addresses variables such as exposure, thermal conditions, roof geometry, drifting, importance, and other factors that can affect the final roof design load.
Michael O’Rourke, Ph.D., P.E., a nationally recognized snow-load authority and longtime engineering professor at Rensselaer Polytechnic Institute, explains that a roof experiences multiple structural loads and that the controlling load depends on the building’s location. His published summary states:
“Depending upon the location, one of these will be the controlling roof live load.”
— Michael O’Rourke, Ph.D., P.E., structural engineering author and snow-load specialist
That is why a metal building designed for one location should not automatically be assumed suitable for another location. Elevation, local snow data, wind exposure, terrain, and jurisdictional requirements can change significantly—even between nearby communities.
Why Open Buildings May Have Different Engineering Limits
Customers sometimes assume an open carport should be structurally simpler than an enclosed garage. From an engineering perspective, however, open buildings can present different wind-pressure and uplift conditions.
Wind can move beneath an open roof and create internal pressure on the underside of the panels. The structure may also have fewer walls available to contribute to the building’s bracing system. As a result, an open-sided structure may require different frame spacing, bracing, anchoring, or load limitations than a comparable enclosed building.
This is one reason customers should not rely only on a general statement such as “engineered for 90 pounds.” The actual engineering must correspond to the exact open, partially enclosed, or enclosed configuration being ordered.
“The correct question is not simply, ‘What snow load does this building have?’ The better question is, ‘Is this exact building configuration engineered for the required loads at this location?’”
— Mike Daniels, Owner, Metal Carports and Buildings
Why Large Openings Matter
Large garage doors, RV doors, equipment entrances, and open drive-through bays can substantially affect structural performance. The surrounding framing must transfer loads around the opening while maintaining an adequate load path through the walls, roof, columns, bracing, and anchors.
A proposed opening that exceeds the generic drawing limit may require an engineered header, additional posts, heavier framing, modified bracing, closer frame spacing, or site-specific calculations.
Customers should identify every proposed opening before the building is ordered, including its width, height, and location. Moving or enlarging an opening after engineering has begun may require revised plans and additional fees.
Current International Building Code provisions distinguish metal building systems from ordinary steel construction because they may combine structural steel, cold-formed steel, panels, cables, connections, and bracing into a highly optimized system. Accurate construction documents are therefore important for both design and inspection.
Why Lean-To Dimensions Matter
A lean-to adds useful covered space along the side or end of a metal building, but it also changes how the structure receives and transfers loads.
The engineer may need to consider the lean-to’s width, outside-leg height, roof slope, frame spacing, attachment points, snow accumulation, potential drifting, wind uplift, drainage, anchors, and interaction with the main building.
A lean-to that is attached to a primary building may be covered when it stays within the generic parameters. A standalone lean-to, loafing shed, or drop-down configuration may fall outside those assumptions and require different engineering.
Customers should also distinguish between a true engineered lean-to and a roof extension or field modification. Adding framing or panels after installation without verifying the engineering can introduce loads that were not included in the original design.
When Are Site-Specific Engineered Drawings Required?
Site-specific drawings may be required whenever a proposed structure does not fit within the available generic engineering.
Common examples include:
- Buildings wider than the generic limit
- Buildings taller than the generic limit
- Side or end openings that exceed the allowable width
- Oversized or unusually tall lean-tos
- Standalone lean-tos
- Loafing sheds
- Drop-down lean-tos
- Higher snow-load locations
- Unusual wind or exposure conditions
- Nonstandard framing configurations
- Complex building layouts
- Designs with multiple connected roof systems
- Risk Category II structures
- Buildings intended for residential occupancy
Site-specific drawings are prepared for the actual project design and location rather than a broad category of structures. They may incorporate the installation address, local design criteria, building dimensions, openings, roof style, intended use, and applicable structural details.
The Metal Building Manufacturers Association emphasizes the importance of clearly defining responsibilities among the manufacturer, project engineer, and other design professionals. A STRUCTURE Magazine seminar sponsored by MBMA states that coordination and communication between the manufacturer and the engineer of record are crucial to project success. The presenters included W. Lee Shoemaker, Ph.D., P.E., and Dustin Cole, P.E., S.E.
Current Site-Specific Drawing Terms
Current estimated lead times for site-specific drawings are approximately 21 to 24 business days, although actual completion times can vary based on engineering workload, project complexity, requested revisions, and the completeness of the information submitted.
Site-specific drawings:
- Must be paid for upfront
- Are priced separately from the building
- Should not be included in the building purchase total
- Are non-refundable
- Require a finalized building design before ordering
- May require additional documents depending on occupancy and use
Because these drawings are prepared for a specific project, customers should carefully review and approve their building dimensions, openings, roof pitch, lean-tos, wall configuration, installation address, and intended use before engineering begins.
“Site-specific engineering should be ordered only after the customer has finalized the building. Changing the width, height, doors, lean-tos, or intended use afterward can mean revisions, more cost, and additional time.”
— Mike Daniels, Owner, Metal Carports and Buildings
Risk Category II and Residential Metal Buildings
A metal building used only for storage, agriculture, or another low-occupancy purpose may be treated differently from a building intended for residential use or regular human occupancy.
Risk Category II commonly includes one- and two-family residences, many businesses, recreational facilities, and other normally occupied buildings. ASCE has described Risk Category II as the most commonly used category and notes that it includes one- and two-family buildings and low- to medium-occupancy businesses.
Examples of proposed uses that may trigger additional review include:
- Barndominiums
- Accessory dwelling units
- Guest houses
- Living quarters
- Home offices
- Residential workshops
- Buildings with bedrooms or sleeping areas
- Regularly occupied commercial buildings
- Structures intended for public use
When an A&A building will be used for Risk Category II residential purposes, professionally stamped architectural drawings must be submitted before site-specific structural drawings can be ordered.
Architectural drawings and structural drawings perform different functions. Architectural plans may address floor plans, occupancy, room layouts, egress, windows, doors, wall assemblies, accessibility, fire separation, insulation, and other code requirements. Structural plans address the building’s load-resisting system.
The International Code Council notes that a comprehensive plan review may evaluate occupancy classification, construction type, height and area, means of egress, fire-resistance requirements, and foundation design.
Metal Building Engineering and Foundation Design
The building superstructure and its foundation should be coordinated. A properly engineered frame still depends on an adequate foundation or anchoring system to transfer downward loads, horizontal reactions, wind uplift, and overturning forces into the ground.
Alexander Newman, P.E., an engineer and published author on metal-building foundations, explains that these systems can create special foundation challenges because they are lightweight and may generate significant wind uplift and horizontal column reactions.
“A strong wind results in a net uplift loading on the foundations.”
— Alexander Newman, P.E., author of Foundations for Metal Building Systems
Foundation and anchoring requirements can vary according to the building design, soil, frost depth, local code, slab configuration, column reactions, and authority having jurisdiction. Generic building drawings may not automatically provide a complete site-specific foundation design.
Customers should ask their local building department whether separate foundation plans, soil information, frost-depth details, or local engineering will be required.
Do Stamped Generic Drawings Guarantee Permit Approval?
No. Engineered stamped drawings do not guarantee that a permit will be issued.
The local city, county, or other authority having jurisdiction has the final authority to review the plans and determine whether additional documents or revisions are required. Local requirements may address zoning, setbacks, easements, property lines, snow loads, wind speeds, frost depth, soil conditions, foundations, fire access, flood zones, occupancy, utilities, architectural review, and local code amendments.
The International Code Council states that a building official examines construction documents for code compliance. Even when drawings have been stamped by an engineer, the jurisdiction may still require a site plan, foundation information, zoning approval, or other project-specific documentation.
Customers should contact the applicable building department before ordering and ask:
- Is a building permit required?
- What ground snow load and wind criteria apply?
- Are stamped structural drawings required?
- Are generic stamped drawings accepted?
- Is site-specific engineering required?
- Are separate foundation plans required?
- What setbacks and zoning restrictions apply?
- Does the intended use change the occupancy or risk category?
- Are architectural plans required?
- Are inspections or special inspections required?
Information Needed to Review Engineering Coverage
To determine whether a proposed metal building may qualify for generic drawings, the following information should be available:
- Complete installation address
- ZIP code
- Building width
- Building length
- Building height
- Roof style
- Roof pitch
- Number of enclosed and open walls
- Width and height of every opening
- Door locations
- Lean-to width and outside-leg height
- Intended use
- Foundation or installation surface
- Required ground snow load
- Required wind speed
- Risk or occupancy category
- Local permitting requirements
Providing complete and accurate information allows the building configuration to be compared with the correct engineering package.
Work With Metal Carports and Buildings
Metal Carports and Buildings designs, coordinates, delivers, and professionally installs engineered metal carports, RV covers, garages, steel buildings, workshops, barns, steel sheds, agricultural structures, and selected commercial building systems.
We serve customers throughout Utah, Idaho, Wyoming, Montana, Washington, Oregon, Colorado, New Mexico, Oklahoma, Kansas, Nebraska, and Texas.
Our team can help customers compare building widths, heights, roof styles, openings, lean-tos, snow-load requirements, and available engineering options. We can also help identify when a proposed design appears to exceed the applicable generic drawing parameters.
Final engineering acceptance, permit approval, foundation requirements, and code interpretation remain subject to the engineer and local authority having jurisdiction.
Need a Ballpark Price or Help Understanding the Engineering Options?
Call 435-250-4446 or request a free, no-obligation quote at metalcarportsandbuildings.com.
Before requesting pricing, gather the installation address, desired building dimensions, intended use, opening sizes, lean-to dimensions, and any snow-load or wind-load information provided by your local building department.
Frequently Asked Questions
What are engineered stamped generic drawings?
Engineered stamped generic drawings are structural plans prepared and stamped by a licensed professional engineer for a defined range of building sizes and configurations. They may be used when the ordered structure remains within all approved limits shown in the drawings.
What is the largest building covered by these generic drawings?
The generic packages discussed in this article generally cover buildings up to 30 feet wide. Applicable height limits are generally 16 feet for the state-specific packages and 12 feet for A&A generic drawings.
Are 20-foot-wide garage-door openings covered?
Openings up to 20 feet may be covered under the generic drawings used for Utah, Washington, Oregon, and Montana. Other state packages described here generally limit side and end openings to 16 feet. The complete building design must also remain within all other engineering limits.
Are lean-tos included in generic engineering?
Attached side and end lean-tos may be included when their width and outside-leg height remain within the applicable limits. Standalone lean-tos are not covered by the generic packages described here.
Are loafing sheds covered?
No. The generic drawing packages described here do not cover loafing sheds.
Are drop-down lean-tos covered?
A&A generic drawings do not cover drop-down lean-tos. A different drawing package or site-specific engineering may be required.
What roof pitches are covered?
The state-specific generic drawings generally cover roof pitches up to 6:12. A&A generic drawings generally cover roof pitches up to 4:12.
What snow load do generic drawings cover?
Generic drawings generally cover up to a 90-pound ground snow load, subject to the applicable building design and drawing limitations. Open buildings may be limited to 80 pounds or less and should be confirmed with the engineering department.
Why can open carports have lower snow-load limits?
Open buildings may experience different wind pressures, uplift forces, and bracing conditions than enclosed buildings. Their allowable loads depend on the exact engineered configuration.
When are site-specific drawings required?
Site-specific drawings may be required when the structure exceeds generic limits, has oversized openings or lean-tos, is located in a higher-load area, has a nonstandard design, or will be used as a Risk Category II or residential building.
How long do site-specific drawings take?
The current estimated lead time is approximately 21 to 24 business days, although actual lead times can vary.
Are site-specific drawings refundable?
No. Site-specific drawings are payable upfront and are non-refundable.
Are site-specific engineering costs included in the building price?
No. Site-specific engineering is priced separately from the building and should not be included in the building purchase total.
Can generic drawings be used for a barndominium or ADU?
Residential structures frequently require Risk Category II engineering, architectural plans, and additional local approvals. Generic storage-building plans should not be assumed sufficient for a barndominium, accessory dwelling unit, or other occupied structure.
Do stamped plans guarantee a permit?
No. Permit approval is determined by the local authority having jurisdiction. Additional zoning, site-plan, foundation, architectural, or engineering documents may be required.
