Reference
Sources: the Primary Documents We Cite
Every substantive claim in this library traces to one of the documents below. Wherever the original is public, the link goes to the official source — not to a summary of a summary. Manufacturer documents are cited and summarized on this site, never republished.
Federal regulations
- 24 CFR Part 3280 — Manufactured Home Construction and Safety Standards (the HUD code). ecfr.gov
- 24 CFR Part 3285 — Model Manufactured Home Installation Standards. ecfr.gov
- 24 CFR Part 3282 — Manufactured Home Procedural and Enforcement Regulations. ecfr.gov
HUD and FHA guidance
- Permanent Foundations Guide for Manufactured Housing (PFGMH) — HUD Handbook 4930.3G (publication HUD-007487), September 1996. hud.gov
- FHA Single Family Housing Policy Handbook 4000.1 — manufactured housing eligibility and foundation requirements. hud.gov
- Guide to Foundation and Support Systems for Manufactured Homes — MHRA / HUD PD&R, March 2002. huduser.gov
Flood, frost, and structural standards
- FEMA 85 — Manufactured Home Installation in Flood Hazard Areas. FEMA Flood Map Service Center
- SEI/ASCE 32-01 — Design and Construction of Frost-Protected Shallow Foundations.
- ASCE 7 — Minimum Design Loads and Associated Criteria (wind exposure, risk category, and seismic design category definitions).
- ANSI A119.5 — Park Model Recreational Vehicle Standard.
Product evaluation reports and manufacturer documents
- ICC-ES ESR-4725 — evaluation report for Boxabl structural insulated panels (2021/2018 IBC and IRC recognition). Current report status verified at icc-es.org before any permit use.
- BXB-000009 Installation Manual (Rev 1.1) and Casita Specifications — Boxabl technical documents, cited for Studio Casita dimensions, weight, R-values, and the manual’s deferral of wind/snow loading to the structural plans. Available via the manufacturer’s technical documentation page.
- Baby Box 120 Spec Sheet (BXB-000029) — cited for the towable-RV classification and weights.
Secondary sources, used only where no primary source exists
- Published national cost surveys and lender-facing industry guides — used for the market cost ranges on foundation cost ranges by type, and labeled as planning figures there.
Reviewed quarterly. Evaluation reports get reissued, manufacturer lineups change, and regulations get amended; each article’s reviewed-by date reflects its last check against these sources. See the methodology for how sources are used.