Timber Carports
Permit-ready structural design for wood-framed carports: post-and-beam framing, NDS-compliant connections, wind and seismic calcs, foundation design.
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Attached Structure Structural Design.
Patio covers, pergolas, sunrooms, second-story additions, and bump-outs all share one design problem: the new structure has to load an existing house that was never designed for it. We verify the existing framing, design the ledger and load path, and produce a permit-ready set the building department will sign.
What's included
Design scope for attached structures
- Field-reviewable framing checks of the existing wall, floor, and roof load path
- Ledger design: lag, structural screw, or through-bolt patterns sized for shear and withdrawal
- New beam, post, and footing design for the attached structure
- Lateral analysis: how the addition transfers shear back into the existing diaphragm
- Flashing and waterproofing detailing at the ledger and roof tie-in
- Coordination with the architect on header sizing and opening reframing
Deliverables
What you receive
- Framing plans, sections, and connection details
- Complete calculations including the existing-condition review
- Ledger and hardware schedule with manufacturer-listed connectors
- Foundation details for new posts, piers, or footings
- Notes for required field verification before construction begins
Applicable codes
We design to
- IRC for one- and two-family attached additions
- IBC for commercial and multi-family attached work
- ASCE 7-16 / 7-22 for revised wind and seismic loads on the existing structure
- NDS and AWC SDPWS for wood framing and shear walls
- Local amendments (CBC, FBC, NYC BC) and any historic-overlay requirements
Permit-readyPermit-readyU.S. jurisdictions
Who it's for
Built for the teams that ship the project
- Residential architects designing additions to existing homes
- Design-build remodelers adding patio covers, sunrooms, or second stories
- ADU builders attaching a unit to a primary residence
- Property owners going through a permitted remodel with an architect or GC
FAQ
Attached Structures — questions, answered
Do you need a site visit to design an attached structure?
We don't visit sites ourselves, but we'll give the architect or contractor a clear field-verification checklist — framing sizes, species, span directions, and conditions to confirm before fabrication.
What if the existing house has no permit history or drawings?
Common. We work from measured field notes and photos, make assumptions explicit on the drawings, and call out the verifications the contractor needs to complete on site.
Can you design a second-story addition on a single-story house?
Yes. We re-run the lateral analysis on the whole structure, check the existing foundations for the new gravity load, and detail any required retrofit shear walls or footing upgrades.
Will the plan-check ask for an existing-conditions structural assessment?
Often, yes — especially for additions that change the lateral system. Our calc package includes that review so it's already part of the submittal.
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Ready to design your attached structures? Let's scope it.
Send your drawings, sketches, or site address — we'll come back with a fixed proposal for the structural scope.