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LONE TREE SERVICES
ADU / Backyard Cottage in Lone Tree
Licensed adu / backyard cottage services for Lone Tree and Douglas County. Build an income-producing unit in your backyard.
- Full Design Lifecycle
- Construction & Tenant Finish
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Real adu / backyard cottage work, delivered
Local Service
ADU / Backyard Cottage Services in Lone Tree, Colorado
Autotelic provides professional adu / backyard cottage services throughout Lone Tree and the surrounding Douglas County area. Accessory dwelling unit construction across the Denver metro — detached new builds, garage conversions, and basement conversions compliant with Colorado HB 24-1152. One veteran-owned design-build team runs the full Denver sequence under a single contract: zoning verification and concept design, municipal zoning and building permit reviews, then construction and inspections through certificate of occupancy. Whether you're in Lone Tree (Park Meadows and RidgeGate) or nearby communities, our team delivers quality workmanship backed by Colorado licensing and full insurance coverage.
Permit Thresholds
Lone Tree permit thresholds
- Code reference
- This aligns with the adopted 2021 International Residential Code (IRC) and amendments (along with other 2021 I-Codes and the 2023 National Electrical Code), as set forth in the City’s municipal code Chapter 18 (Building Regulations).
- Building
- Fences under 7 feet tall; retaining walls under 4 feet; concrete walks, patios, and driveways; painting; swings/playground equipment; same-size window replacements (like-for-like size; changing opening size requires a permit).
- Code reference
- Re-roofing generally requires a permit when replacing more than 1 square (100 sq ft).
- Code reference
- Emergency repairs allow a 24-hour grace period to apply.
- Code reference
- No use tax, building permit valuation-based tax, or similar rate (with or without a basis such as “applied to X% of valuation”) is specified in Lone Tree’s publicly available building department materials.
Codes are amended regularly — verify current requirements with **The City of Lone Tree Building Division (part of the City of Lone Tree Community Development Department) issues residential building permits.
Zoning & ADU
Lone Tree zoning & ADU quick facts
- Code reference
- The most common single-family residential districts in Lone Tree, Colorado, are the SR-E (Estate), SR-L (Low-Density), and SR-M (Moderate-Density) subzoning districts within the SR Suburban Residential District (Lone Tree Municipal Code Sec. 16-2-10).Sec. 16-2-10
- Code reference
- Specific numeric development standards (e.g., maximum lot coverage %, maximum building height, ADU maximum size, or detailed setbacks for additions/ADUs/garages) for these districts are not available in publicly searchable sources, including Municode Chapter 16 excerpts, city PDFs, or related docume
- Code reference
- Standards for accessory buildings/uses, including setbacks, are addressed in sections such as Sec. 16-7-310 (setbacks for accessory uses in SR-E, SR-L, and SR-M), but exact figures are not extractable from available materials.Sec. 16-7-310
- Code reference
- ADU regulations are referenced in third-party summaries (e.g., only one ADU per lot; height limited to the primary residence or 25 feet, whichever is less; size limits of ~50% of primary for attached/internal and ~40% for detached), but these lack direct citations to Lone Tree code sections and cann
- Code reference
- ADUs are generally treated as accessory uses in residential districts where single-family dwellings are permitted, consistent with broader Colorado guidance, but local permitting, size, and placement details require direct consultation with the City of Lone Tree planning/zoning staff or the full Mun
- Code reference
- For precise, current standards applicable to a specific property (including any PUD overlays, which are common in Lone Tree), refer to the official Lone Tree Municipal Code Chapter 16 (Zoning) via Municode or contact the City directly, as standards may be site-specific or updated via ordinance.
Codes are amended regularly — verify current requirements with **The City of Lone Tree Building Division (part of the City of Lone Tree Community Development Department) issues residential building permits.
Energy Code
Lone Tree energy code quick facts
- Code reference
- 2021 International Energy Conservation Code (IECC) with local amendments (per City of Lone Tree Municipal Code Chapter 18, adopted via Ordinance No. 22-07, Series of 2022).Ordinance No. 22-07
- Code reference
- Lone Tree (Douglas County, climate zone 5B) adopts the 2021 IECC by reference with amendments as part of its building regulations.
- Code reference
- State law (HB 22-1362 and related provisions) requires jurisdictions updating building codes to adopt at least the 2021 IECC plus the Colorado Model Electric Ready and Solar Ready Code (with amendments that cannot reduce stringency).
- Code reference
- Key prescriptive requirements relevant to remodels/additions (drawn from the base 2021 IECC for CZ 5B, as specific local numeric energy amendments are not detailed in available municipal sources beyond the general adoption; confirm with the Building Division for exact local tweaks):
- Wall insulation
- R-20 or 13+5 ci (continuous insulation) for wood-frame walls (2021 IECC Table R402.1.2 or equivalent prescriptive path).
- Ceiling/attic insulation
- R-49 (2021 IECC Table R402.1.2).
- Air leakage/air-sealing
- ≤ 3 ACH50 (air changes per hour at 50 Pascals) with blower-door testing required for verification (2021 IECC R402.4; state baseline aligns with this).
- Fenestration U-factor
- Maximum 0.30 for windows (or as per prescriptive table; SHGC requirements also apply in CZ 5).
Codes are amended regularly — verify current requirements with **The City of Lone Tree Building Division (part of the City of Lone Tree Community Development Department) issues residential building permits.
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What an ADU or backyard cottage involves
An accessory dwelling unit (ADU), sometimes called a backyard cottage, is a secondary living unit on a lot that already has a primary home. Common forms include detached backyard cottages, garage conversions, and attached additions with a separate entrance and living space. In the Denver metro, feasibility usually turns on zoning and lot standards, utility capacity, access and parking rules, setbacks, height limits, and how the unit will be used (long-term housing, multigenerational living, or flexible guest space). Early planning should confirm what your city or county allows on your specific parcel before design is locked in.
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Design and site factors that drive the project
Strong ADU plans start with the lot, not just the floor plan. Key inputs include buildable area after setbacks, existing structures and easements, grading and drainage, tree and landscape impacts, alley or side-yard access, and where water, sewer, gas, and electric can connect. Interior planning typically covers a compact kitchen, full or three-quarter bath, sleeping space, storage, daylight, and code-required egress. Exterior design should fit the primary home and neighborhood context while meeting height, lot coverage, and exterior material standards set by the local jurisdiction. Detached units also need clear decisions on foundation type, insulation and energy detailing for Colorado’s climate, and durable exterior assemblies that handle freeze-thaw cycles and sun exposure.
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Permits, inspections, and trade coordination
ADU projects generally require building permits and may also need zoning review, utility permits, and separate trade permits. Requirements vary by city and county across the Denver metro, so the submittal package should match the rules for the property address. A municipally licensed Denver general contractor coordinates the overall project and works with licensed specialty trades for work such as electrical, plumbing, and mechanical systems. That coordination covers sequencing, inspection readiness, and keeping architectural, structural, and MEP details aligned as the unit moves from plans to construction.
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Typical build path
Most ADU projects follow a clear sequence: feasibility and code check, measured site review, schematic design, construction documents, permit submittal, procurement, construction, inspections, and closeout. Detached cottages often involve site work, foundation, framing, roofing, windows, insulation, drywall, finishes, and final utility tie-ins. Garage conversions and attached ADUs can reduce some site work but may add structural, fire-separation, moisture, and existing-condition challenges. Conversion projects need careful assessment of foundation, framing, insulation, head height, and whether the existing shell can support a comfortable, code-compliant dwelling.
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What influences cost without a one-size price
ADU cost is project-specific. Major drivers include unit size, detached versus attached or conversion scope, foundation and site work, utility run lengths and capacity upgrades, kitchen and bath layout, finish level, structural complexity, energy detailing, access constraints, and local permit requirements. Soft costs also matter: design and engineering, survey or site documentation when needed, permit fees, and longer lead times for selected materials. A clear scope and early utility/site review usually reduce redesign and change orders later.
FAQ
Common questions
What is the difference between an ADU and a backyard cottage?
They often describe the same idea: a secondary dwelling on a lot with a primary home. “Backyard cottage” usually means a detached unit behind the main house. “ADU” is the broader planning term and can include detached units, attached units, or conversions, depending on local definitions.
Who handles the trade permits and licensing on an ADU project?
A municipally licensed Denver general contractor coordinates the project and the permit path. Licensed specialty trades perform regulated trade work such as electrical, plumbing, and mechanical, and those trades pull the permits required for their scopes where applicable.
Can every Denver-metro lot add an ADU?
No. Eligibility depends on local zoning and lot standards, including use rules, setbacks, height, lot coverage, parking, and utility constraints. The right first step is confirming what the jurisdiction allows for the specific address and lot configuration.
Is a garage conversion simpler than a new detached cottage?
Sometimes, but not always. Conversions may reuse an existing shell and reduce some site work, yet they can require structural upgrades, insulation and moisture improvements, fire separation, ceiling-height solutions, and new utility routing. A detached cottage adds foundation and full exterior scope but can offer a cleaner layout when yard space and setbacks allow.
How long does an ADU project usually take?
Timeline depends on design complexity, utility work, permit review duration, material lead times, weather, and inspection scheduling. Projects with clear feasibility, complete drawings, and fewer existing-condition surprises generally move more predictably than conversions discovered midstream to need major upgrades.
What decisions should homeowners make early?
Confirm intended use, target size, detached versus attached or conversion, access and privacy needs, parking implications, budget range as a planning input, and whether the unit must function independently year-round. Those choices shape site layout, utility design, and the permit strategy.
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How to start planning
Begin with parcel realities: zoning path, buildable envelope, access, and utility capacity. Then define the unit type and must-have program so design and budgeting stay aligned. From there, construction documents and permit coordination can proceed with fewer revisions. If you are comparing options, bring basic lot information, any prior survey or improvement location certificate if available, rough size goals, and notes on how the unit will be used. That preparation helps a general contractor and design team give a clearer read on scope and sequence.
Service Area
Serving Lone Tree and Douglas County
We serve Lone Tree, CO and all surrounding Denver metro communities. Our team is based in Denver and operates throughout the Front Range, from Castle Rock to Longmont and everywhere in between. Contact us for a free estimate on your Lone Tree project.
FAQ
Common questions
Is an ADU allowed on my lot?
It depends on your city’s zoning — lot size, setbacks, and parking rules vary across the metro. We run the zoning check as the first step and tell you what your lot supports before you spend money on design.
Do you handle ADU permits and inspections?
Yes — ADU permitting is municipal, and we manage zoning review, permit application, and every inspection through certificate of occupancy.
Detached, attached, or garage conversion — which is right?
Each has different zoning, cost, and site implications. We design all three and recommend based on your lot, budget, and how you plan to use the unit.
What does an ADU cost?
Getting a real answer costs less than most people expect: an ADU feasibility consultation is $350, and the full ADU feasibility package — zoning check, site analysis, and concept direction — is $950, both listed at fixed prices on our booking page. Construction cost depends on the path: garage and basement conversions reuse existing structure, while a detached backyard cottage is new construction from the foundation up. After feasibility we quote the build itself as a fixed-price proposal, so you know the number before work starts.
How long does an ADU project take?
Three phases run in sequence: design (site measure, concept, construction documents), permitting (zoning and building review, which move on the municipality’s calendar), then construction. Conversions generally move faster than detached new builds because the shell and foundation already exist. We lay out the phase-by-phase schedule in your proposal, and you track progress on our operations platform once work starts.
How small a lot can support an ADU?
Smaller than most people assume — many Front Range single-unit lots that owners write off can carry a detached unit, and each city sets its own minimum lot size, setbacks, and building coverage. Whether your district’s standards leave room for a backyard cottage — or point you toward a garage or basement conversion instead — is exactly what the feasibility check answers for your address.
What is the ADU permit process?
Two municipal reviews run in order: a zoning review confirming the unit fits your district’s standards, then a building permit review of the construction documents, with inspections during the build and a certificate of occupancy at the end. Colorado HB 24-1152 now requires most Front Range municipalities to allow ADUs on single-unit lots, and we confirm how your city implements it as the first step of feasibility.
How It Runs
01
Survey
02
Design
03
Build
04
Verify
DESIGN SERVICES
Discovery & Site Analysis
Needs + preference programming, site survey, as-built documentation, feasibility.
We walk, measure, and photograph your property — existing conditions, utilities, structure, and constraints. You get the as-built documentation and feasibility read that every later decision rests on.
Learn more →Concept Design & Space Planning
Schematic design, floor plan studies, layout options.
Your scope becomes schematic floor plans you can compare side by side — circulation, daylight, adjacencies, and what each option does to the budget. Layout decisions happen on paper, where changes are cheap.
Learn more →Architectural Design & 3D Renderings
Design development, materials + finishes, photorealistic visualization.
The chosen concept resolves into materials, finishes, fixtures, and lighting — with the automation layer drawn in. Photorealistic renderings let you walk the space and adjust before anything is priced.
Learn more →Construction Documents & Permitting
Full CD sets, structural + MEP engineering coordination, permit-ready drawings.
Approved designs become coordinated architectural, structural, and MEP sheets — the set your jurisdiction permits from and trades build from. We submit, track, and answer review comments.
Learn more →CONSTRUCTION
New Construction & Custom Homes
Ground-up homes and light commercial, dirt to keys.
Ground-up residential and light commercial builds — foundations through finishes, including modular and steel construction. One accountable builder from dirt to keys.
Learn more →Remodels & Additions
Kitchens, baths, basements, pop-tops, whole-home.
Kitchens, baths, basements, pop-tops, and whole-home renovations that respect the house you already have. We handle structure, permits, and the dust.
Learn more →Commercial Tenant Finish & Build-Outs
Shells to working spaces — retail, office, restaurant, school.
Raw shells become working spaces — showrooms, offices, restaurants, schools. Dealer-spec finishes, code compliance, and opening dates held.
Learn more →ADUs & Modular Construction
Backyard cottages, garage conversions, factory-built homes.
Backyard cottages, garage conversions, and factory-built homes — zoning, design, permits, and set. Denver’s ADU rules are a specialty, not a surprise.
Learn more →Outdoor Living & Patio Structures
Decks, pergolas, and dining patios built for Colorado weather.
Decks, pergolas, and dining patios engineered for Colorado sun, snow, and hail — structure, shade, and drainage done right the first time.
Learn more →TECHNOLOGY
Smart Home Automation
Lighting, shades, climate, audio, security — one interface.
Whole-home control of lighting, shades, climate, audio, and security from a single interface — Crestron, Lutron, Savant, and Control4 designed in, not bolted on.
Learn more →A/V Systems
Theaters, distributed audio, video walls, commercial sound.
Theaters, distributed audio, video walls, and commercial sound — designed, installed, and tuned by the same team for over 20 years.
Learn more →Control Systems
Custom programming — scenes and schedules that fit the space.
Every subsystem brought into one elegant interface — custom programming for homes and venues, with scenes and schedules that match how the space is actually used.
Learn more →Networking & Edge Compute
Enterprise Wi-Fi, structured cabling, racks, on-prem compute.
Enterprise-grade Wi-Fi, structured cabling, racks, and on-premise compute — the backbone that makes everything else reliable, including our own Barbot platform.
Learn more →Solar & Energy Storage
Solar arrays, Tesla Powerwall, EV charging — certified install.
Solar arrays, Tesla Powerwall, and EV charging designed and installed by a Tesla Energy Certified team — roof, electrical, and app in one scope.
Learn more →TRUSTED TO BUILD FOR
- Punch Bowl SocialFirst four locations
- Spectrum RetirementSenior living communities
- Denver HighlandsFirst modular custom home
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