Lakewood, CO 80227

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Completed home addition and whole-home remodel with stacked stone and a timber entry on the Front Range
Castle Rock, Colorado · Design-Build

Castle Rock additions, remodels and custom builds.

Design-build in Castle Rock — additions, whole-home remodels, structural work and custom homes, with the wildfire code and the tap-fee arithmetic on the table from the first conversation.

Get a free estimate →How Castle Rock permitting works
Castle Rock, Colorado

In Castle Rock, adding a unit costs $51,890 before anyone picks up a hammer.

Castle Rock’s 2026 system development fees for a single-family three-quarter-inch meter total $51,890 — water, renewable water and wastewater combined — charged at permitting, with a stormwater impact fee on top. That number changes the maths on any project that adds a dwelling unit, and it is the first thing we put in front of a Castle Rock homeowner considering one. It does not apply to an addition or remodel on an existing service.

System development fees$51,890 for a new single-family serviceThe 2026 figure for a single-family three-quarter-inch meter is $51,890 — Water $9,931, Renewable Water $35,829 and Wastewater $6,130 — charged at the time of permitting for new construction. Stormwater impact fees add $1,265 per unit in the Cherry Creek Basin or $2,839 in the Plum Creek Basin. This is the number that decides whether adding a unit pencils, and almost nobody publishes it.
Wildfire Resiliency CodeIt reaches additions and re-roofsThe 2025 Colorado Wildfire Resiliency Code was adopted under Ordinance 2026-009 on 24 March 2026 and takes effect 1 July 2026. Depending on your property’s fire intensity classification — Low, Moderate or High — new construction, additions, re-roof projects and certain exterior renovations may all be subject to it. Material selection becomes a design decision, not a finish decision.
Residential code and engineering2024 IRC, and stamped plans are not optionalCastle Rock’s adopted building codes took effect 30 June 2026 on the 2024 IRC. Residential additions require a geotechnical soils report plus foundation and structural framing plans signed and sealed by a Colorado registered design professional. Local snow-load amendment: 30 psf below 6,000 ft, 35 psf from 6,000 to 6,499 ft, 40 psf from 6,500 to 7,000 ft.
Erosion control and metro districtsA TESC plan gates every permitNo building permit is released without an approved TESC (erosion control) plan and permit in place — in force since 1 July 2019. Separately, Castle Rock’s own mapping shows 39 metro districts, so most addresses sit inside one; that affects fees and covenants even though the Town does not publish a district role in permit review.

Verified against official Town of Castle Rock and Colorado Department of Local Affairs sources as of August 2026. Code editions and ADU rules change, and several Front Range jurisdictions are mid-revision right now. Treat this as the starting point for your project, not as legal advice, and confirm the current standard with Castle Rock Development Services before you commit to a design. We do that on every job as a matter of course.

Straight Answers

Castle Rock questions we get asked.

Why is adding a unit so expensive in Castle Rock?

Because of the system development fees. The 2026 figure for a single-family three-quarter-inch meter is $51,890 – Water $9,931, Renewable Water $35,829 and Wastewater $6,130 – charged at the time of permitting for new construction, with stormwater impact fees of $1,265 per unit in the Cherry Creek Basin or $2,839 in the Plum Creek Basin on top. It is the single biggest variable in a Castle Rock feasibility conversation and we put it on the table first. It does not apply to an addition or remodel running on an existing service.

Does the wildfire code affect my Castle Rock remodel?

It can, from 1 July 2026. The 2025 Colorado Wildfire Resiliency Code was adopted under Ordinance 2026-009 on 24 March 2026. Depending on your property’s fire intensity classification – Low, Moderate or High – new construction, additions, re-roof projects and certain exterior renovations may all be subject to it. If you are planning a re-roof or exterior work, the material specification needs settling before you order anything.

What does Castle Rock require on an addition submittal?

More engineering than most jurisdictions. A residential addition requires a geotechnical soils report plus foundation and structural framing plans signed and sealed by a Colorado registered design professional, and foundation inspections require stamped reports from a Colorado-licensed engineer or registered architect. Separately, no building permit is released without an approved erosion control – TESC – plan and permit in place, which has been the rule since 1 July 2019. Castle Rock is on the 2024 IRC, with a local snow-load amendment of 30 psf below 6,000 feet rising to 40 psf at 6,500 to 7,000 feet.

Completed home addition with stacked stone and a timber entry on the Front Range
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Bring us the house you already love.

We will look at what is standing, what it can carry and what Castle Rock actually charges — then tell you honestly what it takes. It starts with a short phone consult, not a sales visit.

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What We Build

Whole-Home Remodels

Down to the studs where it needs to be, staged so you can live through it where it does not.

Home Additions

Rear, side and bump-out additions engineered to what the existing structure can actually carry.

ADUs

Detached, attached and basement accessory dwelling units, designed to the standard that applies on your lot.

Second Storeys & Pop-Tops

Adding a floor without moving. The structural question gets answered before the design does.

Kitchen Remodels

Layout, structure and services together — most kitchens that disappoint were solved on paper only.

Basement Finishes

Egress, ceiling height, moisture and mechanicals settled before a single wall goes up.

Structural Remodeling

Load-bearing walls, beams and foundations — the work that makes open plans possible.

Custom Homes

Ground-up design-build on your lot, with the same documentation discipline as our remodels.

Nearby

Parker

A five-day completeness check before the review clock even starts, and mandatory town licensing.

Lone Tree

Planned Development zoning — your setbacks live in your PD plan, not the municipal code.

Highlands Ranch

Three separate approvals before a permit issues. We map them before design starts.