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CASTLE ROCK SERVICES
Second-Story Addition in Castle Rock
Licensed second-story addition services for Castle Rock and Douglas County. Double your living space without moving.
What Castle Rock requires
Code reference: Exempt work follows the Town’s adopted amendments to the 2024 International Residential Code (IRC) and International Building Code (IBC), per Ordinance No. 2026-017 (effective around June 30, 2026). Ord. No. 2026-017
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Local Service
Second-Story Addition Services in Castle Rock, Colorado
Autotelic provides professional second-story addition services throughout Castle Rock and the surrounding Douglas County area. Full second-story additions across the Denver metro with structural engineering, framing, roofing, and complete interior build-out. Commercially licensed and insured. Whether you're in Castle Rock (Douglas County seat) or nearby communities, our team delivers quality workmanship backed by Colorado licensing and full insurance coverage.
Permit Thresholds
Castle Rock permit thresholds
- Code reference
- Exempt work follows the Town’s adopted amendments to the 2024 International Residential Code (IRC) and International Building Code (IBC), per Ordinance No. 2026-017 (effective around June 30, 2026).Ord. No. 2026-017
- Code reference
- One-story detached accessory non-habitable structures (tool sheds, playhouses, etc.) ≤ 120 sq ft, ≥ 10 ft from the nearest occupiable structure.
- Code reference
- Fences ≤ 6 ft high (swimming pool barriers of any height are *not* exempt).
- Code reference
- Shingle repair or replacement not exceeding one square (100 sq ft) of covering per building.
- Code reference
- The adopted codes (2024 IRC/IBC and related) govern when alterations trigger permitting.
- Code reference
- See Title 15 of the Castle Rock Municipal Code (and amendments in Ordinance 2026-017) for the full adopted code language on work exempt from permit (primarily amending IRC R105.2 and equivalent IBC sections).Ord. 2026-017
- Building use tax
- 5.2% applied to 50% of the project’s valuation (materials estimated at half the valuation).
- Code reference
- This comprises the Town’s 4.2% use tax rate + Douglas County’s 1% use tax rate.
Codes are amended regularly — verify current requirements with **The Town of Castle Rock Building Division (part of Development Services) issues residential building permits within the town limits.
Zoning & ADU
Castle Rock zoning & ADU quick facts
- R-1 — Minimum Lot Area
- 9000 sfR-1
- R-1 — Minimum Lot Width
- 75'R-1
- R-1 — Front Setback (min)
- 25'R-1
- R-1 — Side Interior Setback (min)
- 7'R-1
- R-1 — Side Setback Abutting Street (min)
- 25'R-1
- R-1 — Rear Setback (min)
- 25'R-1
- R-1 — Building Height (max)
- 35'R-1
- R1 — Front Setback (min)
- 25'R1
Codes are amended regularly — verify current requirements with **The Town of Castle Rock Building Division (part of Development Services) issues residential building permits within the town limits.
The build sequence for a Second-Story Addition project
This service is a component of How a Home remodel project works in Castle Rock.
Energy Code
Castle Rock energy code quick facts
- Code reference
- 2021 International Energy Conservation Code (IECC), with local amendments, as adopted by Ordinance No. 2026-017 (adopted June 2, 2026; effective June 30, 2026), along with the Colorado Model Electric-Ready and Solar-Ready Code.Ord. No. 2026-017
- Code reference
- This applies to Castle Rock (Douglas County, Climate Zone 5B).
- Code reference
- The adoption aligns with state requirements for jurisdictions updating other building codes by the June 30, 2026 deadline.
- Code reference
- Specific local numeric amendments to prescriptive requirements (e.g., R-values, U-factors, or air-sealing thresholds for remodels/additions) are not detailed in publicly available sources beyond references to the base 2021 IECC tables/sections (such as Table R402.1.2 for insulation/fenestration and
- Code reference
- The adopting ordinance incorporates the 2021 IECC by reference with amendments thereto but does not appear to alter the core prescriptive values in available excerpts.
Codes are amended regularly — verify current requirements with **The Town of Castle Rock Building Division (part of Development Services) issues residential building permits within the town limits.
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What a second-story addition covers
A second-story addition in the Denver metro adds habitable floor over an existing house: new floor structure, stairs, roof, windows, and usually electrical, mechanical, and plumbing. The existing foundation and walls have to carry the extra load. A municipally licensed Denver general contractor coordinates the project, design professionals, and licensed specialty trades. Cost is project-specific and depends on structure, roof, and how much of the first floor is opened.
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Structure and zoning height
City and County of Denver Community Planning and Development treats second-story additions as structural review items that exceed IRC prescriptive limits. The residential permitting guide asks for a letter of structural integrity sealed by a design professional who personally inspected the existing foundation and building (DBCA 133.3). Zoning height is measured in feet and stories from the front and rear base planes (Denver Zoning Code Sec. 13.1.2). Plans should show allowed versus proposed height.
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Permits and who coordinates the work
Additions typically need zoning, building, and Sewer Use and Drainage (SUDP) reviews, plus electrical, mechanical, and plumbing when those systems change. Denver Energy Code Chapter 5 [RE] applies to additions. Cities and counties license general contractors. Colorado has no statewide general contractor license. Autotelic acts as a municipally licensed Denver general contractor and coordinates licensed specialty trades plus the design professionals required for the project.
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What buyers should prepare
Target rooms, existing drawings if any, roof and attic photos, and known foundation concerns.
FAQ
Common questions
Do second-story additions need a Denver permit?
Yes. CPD requires building, zoning, and typically SUDP, with structural review because the work exceeds IRC prescriptive limits.
Who handles second-story permits and licensing?
A municipally licensed Denver general contractor coordinates the project, design professionals, and specialty trades. Colorado has no statewide general contractor license.
Can the existing foundation take a second story?
Only after a design professional inspects it. CPD asks for a sealed structural-integrity letter for second-story additions.
How is height measured?
In feet and stories from the zoning front and rear base planes, not just from the sidewalk.
What information helps define scope?
Desired rooms, existing drawings, foundation notes, landmark status, and city or county.
Service Area
Serving Castle Rock and Douglas County
We serve Castle Rock, 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 Castle Rock project.
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 →Let's design your perfect Second-Story Addition together
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