Build the Outdoor Living Space You’ve Always Wanted

Transform your backyard into a beautiful, functional outdoor living space with Cosmo Builders, Northern Virginia’s trusted Design-Build Deck & Porch Contractor. We specialize in custom decks, covered porches, screened porches, front porches, composite decking, pergolas, and complete outdoor living spaces, managing every phase from design and engineering to permits, construction, inspections, and final project completion.

Why Homeowners Choose Cosmo Builders

• 21+ Years of Construction & Project Management Experience
• 100+ Residential, Commercial & Infrastructure Projects Successfully Delivered
• Class A Licensed & Fully Insured Virginia Contractor
• Complete Design-Build, Engineering & Permit Services
• Premium Trex®, TimberTech® & Deckorators® Composite Deck Installation
• Dedicated Project Management & Professional Craftsmanship
• Serving Northern Virginia & Washington, DC
• Free Consultation & Preliminary Project Evaluation

Start Your Whole-Home Remodeling Project With Confidence

One Team. One Contract. One Trusted Construction Partner.

Whether you’re planning a whole-home renovation, open-concept remodel, home modernization, or complete interior and exterior transformation, Cosmo Builders provides expert guidance from planning and permits to construction and final completion.

• Free In-Home Consultation
• Preliminary Budget & Cost Guidance
• Permit & Feasibility Review
• Layout, Design & Remodeling Recommendations
• Class A Licensed Contractor
• 20+ Years of Construction Experience
• 70+ Completed Projects Throughout Northern Virginia

Most homeowners start a renovation or construction project with a clear picture of what they want. The vision of a larger kitchen or a master suite addition with a completely reimagined floor plan is there from day one. What nobody prepares you for is what happens once the project actually begins.

You hire an architect. The architect produces drawings. You take those drawings out to bid and discover the design you fell in love with costs way more than you budgeted. You go back to the architect for revisions. The contractor has questions that the architect did not anticipate. The permit reviewer flags something neither of them flagged. Three months in, you are spending more time managing the communication breakdown between your own project team than you are making decisions about your home.

This horror story is the predictable consequence of how traditional construction projects are structured, where the people who design your home and the people who build it operate in separate lanes with separate incentives.

Our design-build construction in Northern Virginia solves this by merging design and construction services into one integrated process managed by one accountable team. The result is a project experience that is faster and far less stressful than the traditional model.

Building a custom home is not just about adding more space but creating a home that fits how your family actually lives, from the kitchen everyone gathers into the quiet rooms you need for work, rest, or guests.

And most homeowners start with the same question:

Who can I trust to get this right?

Cosmo Builders is a full-service design-build firm serving homeowners across Northern Virginia and Washington, DC. We help with planning, design, permits, and construction, so you have one team guiding the project from the first idea to the final walkthrough.

We build custom homes in McLean, Fairfax, Arlington, Alexandria, Falls Church, Vienna, Great Falls, Reston, Herndon, Ashburn, Leesburg, Woodbridge, Manassas, Washington, DC, and nearby areas.

Whether you want to build on a vacant lot, tear down an older home, or start a new design-build project, we bring the experience, craftsmanship, and care needed to build a home that feels truly yours.

Are you looking to improve your current home? Do you need a reputable contractor to transform your current home into a living space that meets all of your home improvement and remodeling needs? If you live in the Northern Virginia region, you just struck gold because Cosmo Builders is rewriting the home construction narrative in Northern Virginia and its environs.

Please keep reading to find out the services we offer folks looking to improve their homes.

What’s the Difference Between A Home Renovation and A Remodel?

A lot of times, the words “renovation” and “remodel” are often used interchangeably in home building circles. While both words are synonymous, there are slight differences that you ought to be aware of. With a home renovation project, the look and feel of the home or parts of the home are updated without having to change their intended purpose. But with a remodel, the home’s design is altered, and in some cases, the home’s structure is also altered to match this change.

Then remodeling your home is often more expensive than renovating because of the amount of work needed. And since home renovations are often cheaper, you stand to get a better ROI on renovation projects than you’d get on remodeling projects should you choose to sell your home. On the flip side, a home remodel can correct a poor home design. Still, most historic homes are not permitted for remodeling, especially if they have been listed on the National Register of Historic Places.

One more thing, renovating your home may require a permit, but remodeling almost always does.

Cosmo Builders has successfully completed residential additions, structural renovations, commercial construction, and government-funded projects. Our experience includes architectural design, engineering coordination, permitting, construction management, inspections, and final project delivery. Every home addition is managed by a Class A Licensed Contractor to help ensure quality workmanship, code compliance, and professional oversight from start to finish

Home Addition Contractor in Northern Virginia, Room Additions, Second-Story Additions, and Home Expansion Services

Sometimes the house you love just stops being big enough. A new baby on the way. Aging parents moving in. A job that’s now full-time from home. The family you’ve grown into the house you already have, and moving feels like the wrong answer when everything else about where you live is right.

That’s where a home addition comes in. Cosmo Builders is a home addition contractor serving homeowners across Northern Virginia and Washington, DC. We design and build room additions, second-story additions, garage additions, sunrooms, in-law suites, and full structural expansions, adding the space your family needs without making you give up the neighborhood you’ve put down roots in.

A basement can be remodeled into many things, such as an entertainment area, home office, extra bedrooms, Living space, and a basement apartment for rental income. Cosmo Builders is a fully licensed insured construction and remodeling contractor in Arlington, Northern Virginia, and DC. we do it all. From design to permit, electrical to plumbing, from foundations to paint, Cosmo Builders is your one-stop for a stress-free, for all your basement remodeling or finishing project in Alexandria, Arlington, and DC.

Cosmo Builder’s basement experts and Engineering consultant will inspect your basement, make recommendations, and sit down with you and create the basement plan based on your needs.
Cosmo Builders is an excellent basement specialty with happy customers all over North Virginia and Washington DC. Our team of engineers has done this for over 10 years, with the local highly skilled and certified work shipment. We provide whole basement construction, renovation, and finishing services. Make a call to Cosmo Builders in Alexandria, the basement remodeling specialists.

Seeking ‘Garage Builder near me’ We can build a brand-new garage or remodel the one you’ve got.
We combine designing to permitting, from material to construction of garage addition and remodeling project in Alexandria, Arlington, McLean, and DC.
Our designers and project manager will work with you to customize a layout that will suit your specific needs!
At Cosmo Builders, you will get a fully customized garage design by upgrading and adding garage cabinets, garage storage, overhead garage storage, and garage wall storage.
Our designers and project manager will work with you to customize a layout that will suit your specific needs!
At Cosmo Builders, you will get a fully customized garage design by upgrading and adding garage cabinets, garage storage, overhead garage storage, and garage wall storage.

Why Homeowners Trust Cosmo Builders

Your roof, siding, and exterior systems are your home’s first line of defense against weather, moisture, and costly future repairs. Choosing the right contractor can make all the difference.

At Cosmo Builders, we combine practical construction experience, quality craftsmanship, and transparent communication to help homeowners make informed decisions and protect their investment.

• Class A Licensed Contractor
• 20+ Years of Construction Experience
• Roofing, Siding & Exterior Renovation Expertise
• Permit & Inspection Coordination
• Detailed Planning & Project Management
• Quality Workmanship Backed by Experience
• Building Relationships Beyond Construction

Our focus is simple: deliver durable, code-compliant exterior improvements that enhance protection, curb appeal, energy efficiency, and long-term value.

Your bathroom is the first place you visit every morning and is often the last room you use before going to bed. If it looks outdated, too small, or no longer meets your lifestyle, that frustration can quickly become part of your daily routine.

For over 20 years now, Cosmo Builders has been assisting homeowners across Northern Virginia, from McLean and Falls Church to Arlington and Fairfax, turning their bathrooms into beautiful, useful spaces.

Whether you need a complete master bathroom renovation, a powder room update that leaves a lasting impression, or an entirely new bathroom added to your home, we can handle it all and create the bathroom your home truly deserves.