Structural Shells That Save You Time, Money, and Headaches
Bay4 Builders delivers high-quality structural shells (finished on the outside, shell on the inside) designed to simplify the building process. We take care of the hard, technical work so you can focus on finishing your space your way. Downloadable PDF.
Ideal for:
- Developers & investors (STRs, tiny home communities)
- ADUs, aging-in-place, and backyard housing solutions
- Backyard office, pool house
Every shell includes:
- Exterior Siding – Combination of 26-gauge corrugated metal siding and WPC siding or board-and-batten
- Roofing – TPO rubber membrane roofing or standing-seam metal roofing
- Framing & Structure – Engineered floor joists at 16” on center. 2×6 wall framing, 2×10 roof framing with ZIP System panels (size adjusted as required by local snow load conditions), 3/4” AdvanTech subflooring
- Insulation – Floors and ceilings fully insulated to R-50
- Windows & Doors – Energy-efficient windows and exterior doors
- Interior finishes are not included, giving you complete freedom to design, customize, and complete the interior on your timeline and budget.
Your shell is a starting point—not a limitation. It can be finished as:
- Primary residence
- Tiny home or minimalist living space
- ADU or backyard guest house
- Short-, mid-, or long-term rental
- In-law suite or ageing-in-place residence
- Backyard office or professional workspace
- Pool house or guest retreat
- Home gym, yoga studio, or music studio
- and many more — if you can imagine it, a shell can support it.
Zoning, permitting, and use requirements may vary by location.
Many states such as Maryland are encouraging ADUs. Read more here.
A shell lets you skip the hardest, most expensive part of construction — and gives you full control over the rest.
Our building shells are a popular option for customers who want to:
- Get started right away
- Customize their space exactly how they want it
- Skip the most complex phase of construction
- Reduce upfront costs
- Start with a smaller investment and build as funds allow
- Move straight into interior finish-out
- Work on their own timeline, budget, and skill set
- Hire their own contractors or builder
Coming Soon
Model 1340
22’9” x 60′
1,340 sq ft
$150,000
Looking for a move-in-ready unit? In addition to our shell options, we offer fully finished units through our trusted partners:
Fox Enterprises – www.buildwithfox.com
This allows you to start with a shell and have the interior and setup professionally completed from start to finish.
Finished units may include drywall, plumbing, electrical wiring, lighting, full kitchen bathroom, deck, landscaping, driveway, HVAC system and more. Partnering with these providers allows for a seamless transition from shell construction to a completed unit—while maintaining quality, efficiency, and clear separation between shell and finish scopes. An approximate number for finishing after the shell purchase is $100,000.
What This Package Includes
- Fully finished, move-in-ready interior
- Standard kitchen and bathroom package
- Complete mechanical, electrical, plumbing systems
- Flooring, paint, trim, and interior doors
- Appliances and plumbing/electrical fixtures
- Final inspections and professional cleanup
- One-year workmanship warranty
Build Package After Shell Purchase
This package reflects an approximate turnkey construction allowance based on standard specifications and typical site conditions. All pricing is after purchasing the dried in shell from Bay4 Builders and transporting to location.