Colorado Boxabl Casita Gable Roof Engineering Package
The classic pitched profile — pre-engineered gable trusses with a gable end truss, field-installed outriggers, blocking, and venting over the SIP roof. The state approval covers the box — the site-built roof needs its own engineering for your local permit. This is it.
What You Get
- Site-specific design criteria sheet for your truss manufacturer (wind, exposure, snow, seismic)
- Truss-to-SIP eave connection detailing with A35 clip spacing calculated for your site
- Bottom-chord uplift bracing detail (2x6 glued + fastened per the Boxabl system)
- Sheathing nailing schedule — including the high-wind 4"oc perimeter tightening when your site requires it
- Seismic orientation determination (Orientation #2 is mandatory in SDC D/E)
- Sealed by a PE licensed in Colorado, formatted for permit submittal — one revision cycle included
What You Send Us
- Project address
- Which roof option you’re building (or ask — we’ll advise)
- Your foundation plans (ours or existing)
- Truss supplier, if already chosen (not required)
- Roofing material preference
Delivered within 5 business days after full documentation.
Why the Gable Roof Needs Site Engineering in Colorado
Your roof package is engineered to Colorado's actual conditions: design winds 105–140 mph; low seismic; significant ground snow loads in parts of the state. Boxabl's sheets tighten nailing schedules above 130 mph (Exp. B) / 110 mph (Exp. C), require thicker sheathing above 70 psf combined snow + roofing weight, and mandate truss Orientation #2 in Seismic Design Categories D and up — all determinations this package makes for your parcel.
Typical design basis for these packages: current IBC/IRC as adopted by your jurisdiction, Risk Category II, with wind, seismic, frost, and soil-bearing values set site-specifically for your parcel. Sample criteria shown in our public materials (e.g., Exposure C, 140 mph ultimate wind, ~2,000 psf assumed bearing) are illustrative only — your stamped set uses your site’s values.
Questions
Doesn't Colorado's Boxabl approval already cover the roof?
No — state modular approvals cover what's built in the factory. The gable roof is site-installed construction, permitted by your local building department with site-specific engineering. Boxabl's own roof sheets state "site-specific design criteria to be provided by a licensed engineer," and connection details must be designed by an engineer licensed in the state of installation.
What about the truss shop drawings?
Those come from your truss supplier's engineer — but they design to criteria someone must give them. Our package includes the sealed criteria sheet (wind, exposure, snow, seismic for your parcel) you hand to any truss manufacturer, plus everything the trusses connect to.
Can I use tile roofing in Colorado?
In most of Colorado, yes — the tile prohibition on Boxabl's sheets applies only in high Seismic Design Categories (D/E/F). Your package confirms your site's category and documents what's allowed.
Does this bundle with foundation plans?
Perfectly — same intake, same site data. Foundation plans ($749) plus the roof package ($449) gives you the complete site-engineering set for your permit in one submittal.
Foundation + Roof = the Complete Permit Set
Bundle the Colorado foundation plans ($749) with this roof package ($449) — one intake, one sealed submittal, everything your building department asks for.
Questions first? Call 813-694-8989.
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