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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.

What Lone Tree requires

SRL — Front Setback (min): 25' SRL

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ADU / Backyard Cottage

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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

SRL — Front Setback (min)
25'SRL
SRL — Side Interior Setback (min)
15'SRL
SRL — Side Setback Abutting Street (min)
15'SRL
SRL — Rear Setback (min)
25'SRL
SRL — Building Height (max)
35'SRL
SR-L — Front Setback (min)
25'SR-L
SR-L — Side Interior Setback (min)
15'SR-L
SR-L — Side Setback Abutting Street (min)
15'SR-L
Lone Tree Municipal Code Chapter 16 Art. VII §16-7-290 (Ord. 22-02 Art. 4) SRL setback standards (16-7-290 Development standards of SR-E, SR-L and SR-M) — effective 2022-01-01 · Lone Tree Municipal Code Chapter 16 Art. VII §16-7-290 (Ord. 22-02 Art. 4) SR-L setback standards (16-7-290 Development standards of SR-E, SR-L and SR-M) — effective 2022-01-01Source: library.municode.com

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.

A recent build

Backyard ADU in Denver

Denver · 2026

Status
Under construction — 2026
Managed on
Buildbot — Autotelic’s own PM platform
  • Architecture, site plans, and full MEP design completed in-house
  • Permits pulled — electric and plumbing rough-ins permitted and underway
  • Spray-foam insulation and exterior work in progress
  • First project managed end-to-end on Buildbot, Autotelic’s construction-PM platform

A ground-up backyard ADU in Denver — designed, permitted, and now under construction by Autotelic, and the first project managed end-to-end on Buildbot, Autotelic’s own construction-management platform.

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).Ord. 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 this covers

Detached or attached accessory dwelling on a Denver lot: foundation or module, envelope, and utility tie-in. Height and massing follow Denver bulk-plane and ADU rules for the zone; confirm with CPD before drawings freeze.

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How the work is coordinated

A municipally licensed Denver general contractor coordinates licensed specialty trades for electrical and plumbing. Denver-metro work is permitted locally. Colorado has no statewide general-contractor license. Cities and counties license general contractors. DORA licenses electrical and plumbing (and similar regulated trades), not general contractors. Autotelic is a municipally licensed Denver general contractor that coordinates licensed specialty trades. Denver building permits run through Community Planning and Development (CPD). Costs are project-specific; no dollar figures.

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

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