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A Boulder-Based General Contractor Built Around One Standard
Cosman Construction is a boutique design-build firm serving homeowners, property owners, and property management companies across Boulder County who want a general contractor they can actually trust with their home.
We specialize in the full range of residential construction — outdoor living spaces and custom deck building, exterior remodeling, interior remodeling, home additions, and design-build projects — all managed under one contract with one point of contact from start to finish.
Every project starts with a no-cost conversation with Alex — an honest assessment of your space, your goals, and what the project actually requires before any design decisions are made. From there we produce full drawings, a written scope, and a real estimate. And if you decide to take that design and work with another contractor for the build, that's completely your call — if you choose to build with us, the design fee is credited toward the project cost. That's been the standard since Alex founded the company in 2013 — every client gets direct access to the person responsible for their project, and that person is still there on the last day of the build.
Homeowners across Boulder, Longmont, Lafayette, Louisville, Erie, and the surrounding Front Range have trusted us with their most significant investments — and they come back because that standard has never changed.
Meet Alex Cosman
Alex Cosman grew up in Boulder. He knows what the housing stock looks like — the ranch homes and split-levels built before anyone was thinking about open floor plans, the older bungalows in neighborhoods that haven't changed much in forty years, the mountain properties where every project comes with its own set of site-specific challenges.
He founded Cosman Construction in 2013 around a straightforward operating principle: keep the project load manageable enough that he can be present on every job — from the first design conversation through the day the permit closes.
When you reach out to Cosman Construction, you speak with Alex — not a sales rep, not an estimator, not a project manager who joined after the contract was signed. He personally oversees every job site, manages every trade relationship, and holds every project to the same standard regardless of whether it's a design refresh or a full home addition.
That level of involvement isn't a differentiator — it's just how Alex thinks a construction company should be run. And it's the reason clients across Boulder County keep coming back.
Our Mission
We build to a standard we'd be comfortable living with ourselves — because the homes we work on belong to real families, and the work we leave behind reflects on the people who trusted us to do it.
The goal is simple: be the general contractor in Boulder that homeowners refer to their neighbors without hesitation. Not because we're the largest firm in the market, but because we're the most accountable one.
Every decision we make — from material selection to trade coordination to how we communicate mid-project — comes down to one question: is this the way we'd want it done if it were our own home?
Planning Is Where Great Projects Begin
Step 1: Consultation & Design
Every project starts with a conversation with Alex — not a sales rep, not an estimator. From there we produce design drawings, a written scope, and a real estimate so you know exactly what the project costs before deciding whether to move forward.
Step 2: Project Begins
Once design is approved and permits are in hand, work begins on a defined schedule with phase milestones and target dates. Alex is reachable directly throughout, and if anything changes you hear about it before it becomes a problem.
Step 1: Project Completion
Alex walks every inch of the finished work against the original scope. Anything that doesn't meet standard gets corrected before the final walkthrough — not flagged during it. Permits closed, documentation handled. Done means done.
A note on the design phase: You're not locked into completing construction with us. If you take the design we've produced and work with another contractor for the build, that's completely your call. If you choose to move forward with us, the design fee is credited toward the project cost.
The Cosman Construction Difference
Cosman Construction sits in a space that's genuinely rare in this market — experienced enough to handle complex multi-phase residential projects, and small enough that every client gets Alex's direct involvement throughout.
We don't take on more work than we can manage at the standard we've committed to. Every client gets the version of Cosman Construction they hired — not a delegated version of it.
Homeowners researching remodeling contractors across Boulder County will find contractors who are larger, faster, and cheaper. What's harder to find is a builder who will tell you honestly what your project requires, give you a real number before asking for a commitment, and show up every day until it's done correctly. That's what we offer. If it's what you're looking for, we'd like to hear about your home. Call us today 303.775.6690
Our Work
Projects completed across Boulder County — custom decks built to WUI compliance standards, exterior transformations combining siding and structural work, interior remodels that reconfigured floor plans previous contractors wouldn't touch, and home additions that matched the architectural character of homes built decades before we arrived. Browse the full project gallery to see the standard we hold every project to.
