Roof Extension Structural Design
A roof extension must be designed to safely connect with the existing building and transfer new loads through the structure below. This is important for home additions, second-story extensions, porch roofs, garage extensions, ADUs, and remodel projects where the roofline is being changed or expanded.
Framing And Load Path Review
The design starts by reviewing the existing roof framing, proposed roof shape, span lengths, bearing walls, ceiling layout, wall locations, beams, posts, and foundation support. The new roof extension must have a clear load path from rafters, trusses, ridge beams, hips, valleys, and headers down to the walls and foundation.
Snow, Wind And Seismic Checks
Roof extensions may need structural calculations for roof dead load, roof live load, snow load, wind uplift, and seismic forces. In snow regions, the design must check roof slope, drift areas, roof valleys, supported spans, and member deflection. In seismic regions, the roof diaphragm, connections, anchors, shear walls, and lateral load path must be reviewed.
Code-Based Design
- IRC: For residential roof framing, additions, and remodels.
- IBC: For larger, mixed-use, commercial, or non-standard projects.
- ASCE 7: For snow, wind, seismic, dead, live loads, and load combinations.
- NDS: For wood rafters, ridge beams, headers, posts, and connection checks.
- AISC: For steel beams, columns, plates, and structural connections where required.
What We Can Provide
- Roof extension structural design
- Roof framing plans
- Rafter and ridge beam sizing
- Hip and valley framing checks
- Beam, header, and post calculations
- Snow load calculations
- Wind uplift checks
- Seismic load path review
- Connection and anchorage details
- Existing structure support review
- Permit-ready structural drawings
Need Roof Extension Calculations?
Send your floor plan, roof plan, elevations, AutoCAD files, photos of the existing structure, project location, and any permit comments. We can prepare roof extension structural drawings and calculations for snow, seismic, wind, and gravity load requirements.