Boxabl Casita Studio: Foundation Plans & Requirements
The flagship 361 sq ft single-module Casita — now with statewide approvals in Texas, California, and Nevada.
Key Specs for Foundation Design
Square Footage
361 sq ft
Footprint
19' x 19'
Configuration
Studio / 1 Bath
Weight
Single module, roughly half the shipping weight of the 2-Bed (which is 13,000 lbs for two modules)
What the Casita Studio Foundation Must Do
Single-module unit with a 19' x 19' bearing footprint — slab-on-grade, stem wall/crawlspace, and pier & beam all work, chosen by climate and soil.
Perimeter load path follows the SIP wall panels (ESR-4725 axial capacity 2,200 plf), so foundations are designed as continuous perimeter support with engineered anchorage rather than point loads.
Wind uplift anchorage (anchor bolts/hold-downs) is the item building officials look for first — the unit is light relative to its sail area.
In 2026 Boxabl announced Casita Studio approvals including Texas state-level approval and a reduction of required factory inspections in California — meaning more jurisdictions accept the unit with a site-specific, PE-stamped foundation plan.
Approval status: Texas state approval (May 2026); California statewide modular approvals with reduced in-plant inspections (2026); Nevada statewide approval (2026). Other states: local/state pathway with PE-stamped site plans.
Foundation Options & Typical Costs
National planning ranges — your state's frost depth, wind, seismic, and soils pick the winner. Find your state on our state-by-state guides.
Concrete Slab
from $6,000A single layer of concrete, several inches thick. Simple and cost-effective.
Best for: Flat terrain, warm climates, budget-conscious projects
Crawlspace
from $12,000Elevates the home 18-36 inches, providing access to plumbing and electrical systems.
Best for: Sloped lots, areas with moisture concerns, easy maintenance access
Pier & Beam
from $5,000Concrete piers supporting beams and joists. Ideal for challenging terrain.
Best for: Sloped lots, rocky soil, environmentally sensitive areas
Full Basement
from $25,000A full-height underground level, offering additional living or storage space.
Best for: Cold climates, need for extra space, areas with deep frost lines
Casita Studio FAQs
What foundation does the Casita Studio need?
A permanent, code-compliant foundation — typically slab-on-grade in warm climates, stem wall/crawlspace where frost depth requires it, or pier & beam on sloped lots. Every option needs engineered anchorage for wind uplift, documented in a PE-stamped plan for your permit.
How much does a Casita Studio foundation cost?
Typical construction runs about $5,000–$12,000 for slab or piers depending on region and site, plus engineering plans from $749. Crawlspace and basement options cost more.
Can I put a Casita Studio in my backyard as an ADU?
In most states yes, subject to local zoning — lot setbacks, size limits, and utility connections. States like California, Washington, Texas, and Montana now have laws requiring cities to allow ADUs.
We provide foundation engineering only — Boxabl units are sold separately by Boxabl Inc. Specs above reflect Boxabl's published documentation and may change; always confirm current specs with the manufacturer.