Custom homes often require structural engineering when the design includes large clear spans, cantilevered elements, complex roof geometries, hillside foundations, or materials beyond standard prescriptive construction. Our new building structural engineering team works with custom home builders and architects across all 50 states to produce the stamped structural drawings their projects require.
When a Custom Home Requires a Structural Engineer
Many standard homes are built from prescriptive construction methods described in the IRC (International Residential Code), which provide span tables, wall stud sizing, and shear wall requirements that trained builders can follow without a structural engineer. These prescriptive methods work well for typical configurations within defined limits, but custom home designs frequently push outside those limits.
Large open-plan living spaces with clear spans exceeding the IRC span tables require engineered beams sized by a structural engineer. Cantilevered decks or floors extending beyond what prescriptive tables allow need engineering. Hillside lots with complex foundation configurations on varying soil and rock require site-specific foundation design. Second stories added to existing foundations require verification that the existing foundation and framing can carry the additional load.
Unusual or mixed structural materials fall outside prescriptive construction methods entirely. A home using structural steel columns and beams, cross-laminated timber panels, structural insulated panels, or concrete construction requires a structural engineer regardless of size. Our team has experience with all of these material types and has provided specialty structural engineering for architecturally complex residential projects.
What the Structural Engineer Designs vs. What the Architect Handles
The architect or building designer is responsible for the floor plan, elevations, sections, finish specifications, and the overall architectural vision of the home. The structural engineer is responsible for sizing all load-carrying structural members and connections so that the building meets the applicable code requirements for safety.
In practice, the two disciplines must coordinate closely because architectural decisions drive structural requirements. A cathedral ceiling eliminates the attic space where the structural engineer might otherwise run collar ties and ridge beams. A cantilevered balcony requires structural elements that penetrate the thermal envelope and must be detailed to avoid thermal bridging. A stone exterior adds dead load that the foundation must accommodate. The earlier in the design process the structural engineer is involved, the easier these coordination issues are to resolve.
What the Structural Drawings Include
Foundation Plan
The foundation plan shows the location and size of all footings, grade beams, pier pads, or other foundation elements. Footing sizes are calculated based on the column and wall loads coming down from above and the allowable bearing capacity of the soil at the project site. In hillside conditions, the foundation may include both shallow and deep elements to address variable slope conditions. Our structural engineering team designs foundations for all soil and site conditions.
Floor and Roof Framing Plans
Framing plans show the size and spacing of all joists, beams, rafters, and ridge members for each level. Engineered lumber products like LVL beams and I-joists are commonly specified for long spans because they provide greater strength and less variation than sawn lumber. Steel beams or columns may be specified at specific locations to achieve the span or load requirement the architect’s design demands.
Shear Wall Schedule
The shear wall schedule shows which walls are designated to resist lateral loads from wind and seismic events, and what sheathing, nailing pattern, and hold-down hardware those walls require. Custom homes with large window openings or open floor plans have less available wall length for shear walls, which makes the shear wall design more critical and sometimes requires steel moment frames at specific locations.
The Permit Review Process
Custom homes typically go through plan check at the local building department, which reviews the architectural and structural drawings for code compliance. In most jurisdictions, plan check for a custom home takes two to eight weeks. Complex designs or projects in jurisdictions with high plan check volumes may take longer. Plan check comments requiring responses are common and add time to the permit process.
Working with an engineer who has experience submitting to your local jurisdiction reduces the number of comments because the drawings address the common concerns up front. Our team tracks jurisdiction-specific requirements and prepares drawings accordingly. Learn more about our process at rightangleeng.com/engineering.
When the Inspector Has Questions During Construction
Building inspectors occasionally encounter conditions during framing inspection that differ from the approved drawings. This may be a beam that was substituted in the field, a connection detail that was modified, or a structural element that was altered to accommodate a mechanical penetration. The inspector may place a hold on the project until the engineer of record reviews the as-built condition and provides a response.
Having a responsive engineer of record is important for keeping the construction schedule moving. We respond promptly to inspector inquiries and provide written responses with any required supplemental drawings.
Frequently Asked Questions
Does every custom home need a structural engineer?
Not every custom home requires a structural engineer, but many do. If your design falls entirely within the prescriptive limits of the IRC, you may be able to build without an engineer in jurisdictions that allow it. If any element of the design exceeds prescriptive limits, or if your jurisdiction requires engineering for all custom homes, an engineer is required.
How long does custom home structural engineering take?
For a straightforward custom home with standard materials and no unusually complex elements, structural drawings typically take two to four weeks. Homes with complex structural systems, unusual materials, or hillside foundations take longer because more design work is required.
Can the structural engineer work from the architect’s design intent drawings, or do they need full construction documents first?
Structural engineers can begin the design process from schematic or design development drawings, which allows structural decisions to be incorporated into the architectural development before construction documents are fully complete. This early engagement reduces the number of design changes required later and produces more efficient structural solutions.
Start Your Custom Home Structural Project
We provide PE-stamped structural engineering for custom homes in all 50 states. Submit your project at rightangleeng.com/get-started.
References
International Residential Code for One- and Two-Family Dwellings. (2021). International Code Council.
American Wood Council. (2018). National Design Specification for Wood Construction. Leesburg, VA.
American Institute of Steel Construction. (2016). Steel Construction Manual, 15th Edition. Chicago, IL.