Home Addition · Castle Rock, Douglas County, Colorado

Home Addition Contractor in Castle Rock

Brothers 59 Construction delivers square-footage addition in Castle Rock — foothills, gambel oak meadows, and ridge views toward the Front Range. Typical project range $900K–$4M; transitional and mountain-modern residences. 5.0/5 rating across 19 verified Google reviews.

Phone: 303-434-7658 · Email: michaelglivar1@gmail.com

Cost Guide

Home Addition Cost in Castle Rock, Douglas County (2026)

TierInvestment RangeWhat's Included
Refined$150K–$350KSingle-story addition (300–600 sq ft) with matched exterior, quality finishes, and standard structural work
Signature$350K–$700KTwo-story or complex addition with new foundation, premium windows, custom millwork, and integrated HVAC/electrical upgrades
Architectural$700K–$1.2M+Large multi-room wing or in-law suite with architectural glazing, structural steel, and estate-grade finishes throughout

Where the investment goes: Labor & trades 45–55% · Materials & fixtures 30–40% · Design, permits & mgmt 12–18%.

What drives Castle Rock Home Addition cost

Additions in Douglas County run $450–$800+ per square foot at the luxury level because tying new structure into an existing home requires foundation matching, roofline integration, and utility rerouting. Matching original stone, stucco, or custom siding on established Castle Rock and Highlands Ranch estates drives material premiums. Setback, height, and HOA architectural-review constraints often add engineering and design cost before a shovel hits the ground.

Scope of Work

Home Addition in Castle Rock

Site-built additions integrated to the original architecture: bump-outs, second-story pop-tops, attached suites, and connector galleries.

Trade Depth & Schedule

Structural engineering, foundation extension, roof tie-in, MEP extension, and seamless interior/exterior finish matching.

Specification & Brands

Marvin, Andersen, James Hardie, GAF, CertainTeed

Castle Rock Communities

Active across The Meadows, Founders Village, Castlewood Ranch, Plum Creek, Cobblestone Ranch and surrounding Castle Rock neighborhoods, with HOA-compliant design review packages prepared to each ARC standard.

Market Authority

Douglas County Permit Activity

Brothers 59 Construction publishes monthly Douglas County permit reports sourced from official county records.

View the full monthly permit report →
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Home Addition in Nearby Douglas County Communities

Home Addition in Castle Pines → · Home Addition in Castle Pines Village → · Home Addition in Castle Pines North → · Home Addition in Parker →

FAQ

Home Addition in Castle Rock — Frequently Asked

Why does an addition cost more per square foot than a new build?

Additions require demolition, structural integration, and finish-matching to existing construction, plus working around an occupied home — all of which add labor complexity absent in ground-up building.

Will an addition require HOA and County approval?

Yes — most Douglas County communities require HOA architectural review for exterior changes, and the County requires structural permits and inspections for any square-footage addition.

How long does a luxury addition take?

Expect 6–12 months depending on scope; two-story additions with new foundations and structural upgrades sit at the longer end due to engineering and inspection sequencing.

Contact

Start Your Castle Rock Home Addition Project

Phone: 303-434-7658 · Email: michaelglivar1@gmail.com