Aurora is one of Colorado’s fastest-growing cities for accessory dwelling units, but every ADU permit still depends on engineered, stamped structural plans. As an ADU structural engineer in Aurora, ISTA Engineers prepares the foundation design, framing, and load calculations your project needs, sealed by a Colorado-licensed Professional Engineer and drawn to fit Aurora’s specific rules and soils.
Talk to a Aurora ADU Structural Engineer
Permit-ready, PE-stamped plans for detached, garage-conversion, and basement ADUs across Aurora.
We work with Aurora homeowners, contractors, and architects to turn a design into a structurally sound plan set that clears Aurora Planning & Development Services — whether it is a detached backyard cottage, a garage conversion, or a basement unit.
Why an Aurora ADU Needs a Structural Engineer
An ADU is a complete, independent dwelling with its own structural system, so Aurora treats it like new residential construction. Engineered foundation and structural plans are part of the building permit, and your build passes separate foundation and framing inspections.
In Aurora there is an added reason the engineering matters: much of the area sits on expansive clay soils, so the foundation is not a formality — it is the part of the design that keeps the building level and sound for decades. That is exactly what a structural engineer is there to get right.
Aurora Rules That Shape Your Structural Plans
Aurora’s zoning is governed by the Unified Development Ordinance (Chapter 146), and as a subject jurisdiction under Colorado’s state ADU law, Aurora allows ADUs on single-family lots through an administrative process. The standards below shape the structure, and we design around them from the start.
Aurora’s UDO and Height Limit
Aurora generally limits an ADU to about 24 feet in height and no taller than the primary home, along with architectural-compatibility and private-outdoor-space standards. The height envelope directly drives the roof and wall framing, so we design the structure to fit it.
The Three-County Factor
Aurora is unusual: it spans Arapahoe, Adams, and Douglas counties. The city’s UDO governs zoning citywide, but soil conditions and property records can vary across that footprint. We confirm the requirements and the ground conditions for your specific parcel before we design.
Expansive Soils and Frost Depth
The eastern Denver metro, including much of Aurora, is known for expansive clay and claystone that can heave when moisture changes. Foundations must be engineered specifically for those soils, and footings must bear below frost depth. This is the single most important structural consideration for many Aurora ADUs, and a common focus of plan review.
Buckley Space Force Base Compatibility
Some Aurora properties fall within Buckley Space Force Base compatibility zones, which can add height or development limits. Where it applies, we account for it in the design so the structure stays compliant.
What We Deliver for Your Aurora ADU Permit Set
Our goal is a coordinated, permit-ready package Aurora P&D can approve without a round of corrections. A typical Aurora ADU structural set includes:
- Foundation design — footings and details engineered for Aurora’s expansive soils and frost depth.
- Structural load calculations — snow, wind, seismic, and gravity loads for your design.
- Framing plans — floor, wall, and roof framing within Aurora’s height envelope.
- Lateral / shear design — the bracing and load path that resist wind and seismic forces.
- PE-stamped drawings & calc package — sealed by a Colorado-licensed Professional Engineer.
- Plan-review support — we respond to Aurora P&D comments to keep your permit moving.
For a full breakdown of the package, see our guide to what’s in an ADU permit set in Colorado, and more on ADU foundation design.
ADU Types We Engineer in Aurora
Detached ADUs and Backyard Cottages
A standalone Aurora backyard unit needs a complete structural system from footings to roof — and on Aurora soils, the foundation design is where it starts. See detached ADU structural engineering.
Garage Conversion ADUs
Converting an Aurora garage is rarely just adding walls. The existing slab and foundation were built for vehicles, not living space, and usually need evaluation or reinforcement. See garage conversion structural engineering.
Basement and Internal ADUs
Basement units bring beam and header changes, possible underpinning, and egress requirements. Our basement ADU structural plans handle the structural side of all of it.
The Aurora ADU Permit Process & Timeline
Engineering happens early, right after design, so your building-permit submittal to Aurora Planning & Development Services is complete the first time. A complete, code-compliant package is the best way to avoid the resubmittals that stretch a timeline. Your build then passes standard inspections, including foundation and framing. For cost expectations, see our guide to the cost of a structural engineer for an ADU all of it.
Why Aurora Homeowners, Builders & Architects Choose ISTA
Permit-focused plans designed to clear Aurora P&D review with fewer corrections.
Colorado-licensed Professional Engineers who seal every Aurora plan set.
Expansive-soil experience across the Denver metro — foundations engineered for Aurora ground.
Certified WBENC, WOSB, MWBE, and DBE — a women-owned, minority-owned firm.
Aurora ADU Structural Engineering FAQ
Do I need a structural engineer for an ADU in Aurora?
Yes. Aurora requires engineered, PE-stamped foundation and structural plans for an ADU building permit, whether it is detached, a garage conversion, or a basement unit.
Why do Aurora ADUs need careful foundation design?
Much of the Aurora area sits on expansive clay soils that can heave. Foundations must be engineered for those soils and for frost depth, which is one of the most important parts of a durable ADU.
Does it matter which county my Aurora property is in?
Aurora spans Arapahoe, Adams, and Douglas counties. The city’s UDO governs zoning, but soils and records can vary — we confirm the requirements for your specific parcel.
How tall can an ADU be in Aurora?
Aurora generally limits ADU height to about 24 feet and no taller than the primary home. We engineer the framing to fit that envelope.
How much does ADU structural engineering cost in Aurora?
Typically $2,000 to $5,000 — about 1 to 3 percent of project cost — separate from Aurora permit fees.
Can you engineer a garage conversion or basement ADU in Aurora?
Yes. Garage slabs often need evaluation, and basement units require egress details — both of which we engineer into the permit set.
Get Your Aurora ADU Plans Started
Tell us about your Aurora ADU and we’ll outline exactly what your lot allows and what your structural permit set will include. Request a consultation or call (720) 740-4060.