Accessory dwelling unit builders — Westminster, CO

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.

About this service

These are specialized contractors who focus specifically on the design and assembly of secondary housing units. Unlike general contractors who take on all home renovations, these specialists understand the unique constraints of building in backyards or converting existing structures. You need them when you want someone who manages the entire process—including permits and site management—specifically to ensure your ADU is built efficiently, correctly, and according to the specific regulations governing secondary structures on residential lots.

Frequently asked in Westminster

Also serving nearby: Arvada · Thornton · Denver · Lakewood · Boulder

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Westminster — population 114,875; about 3,633 residents per square mile across 31.6 sq mi. ZIP codes covered include 80030, 80031, 80035, 80036.

Neighborhoods served in Westminster: Countryside, Walnut Creek, Willow Creek — and every surrounding area.