A small wooden house with a woman standing at the open door, surrounded by outdoor furniture including red chairs and colorful potted plants, with a shed to the right and a row of tall evergreen trees in the background.

Expand Your Home With Seamless Additions & Accessory Dwelling Units (ADUs)

When you need more space, Metro Custom Builders delivers custom home additions and accessory dwelling units (ADUs) that blend perfectly with your existing home. Serving Georgetown, Round Rock, Cedar Park, and the greater Williamson County area, we design and build expansions that increase comfort, flexibility, and property value.

Many families also upgrade interiors during an addition. Explore our kitchen remodeling and bathroom remodeling services for seamless design inside and out.

Construction site of a house with a partially built wooden frame, a ladder leaning against it, and trees in the background.

Why Consider an Addition or ADU?

Life changes — your home should too. Whether it’s a growing family, an aging parent moving in, or the need for rental income, an addition or ADU provides:

  • Extra bedrooms or guest suites

  • Private living space for family or tenants

  • Home offices or creative studios

  • Long-term investment and resale value

Some homeowners choose to expand even further with a whole-home remodel

Construction worker wearing a yellow helmet and safety vest working on a wooden framing structure.

Our Additions & ADU Services

We handle every type of expansion project, including:

  • Second-story additions

  • Garage conversions

  • Detached guest houses and casitas

  • In-law suites and multigenerational spaces

  • Kitchen or living room expansions

Interior view of a house under construction, showing exposed wooden framing, pink insulation in walls, a window on the right, and construction materials like metal beams, ladders, and wood planks.

Design & Craftsmanship That Fits

Our team ensures additions don’t look “tacked on.” We match exterior materials, rooflines, and interior finishes so your new space flows seamlessly with the existing home.

People working on architecture models and blueprints of houses on a table, with small house models, measuring tools, and drafting equipment.

Our Process

  1. Consultation & Feasibility – We review zoning, utilities, and your vision.

  2. Design & Estimate – Floorplans, renderings, and detailed pricing.

  3. Permitting & Prep – HOA approvals, engineering, and permits.

  4. Construction & Completion – On-time, high-quality builds you can trust.

See our detailed remodeling process to understand how additions and ADUs fit into a full project flow.

Cost & Timelines

Digital illustration of a building exterior with a hand drawing outline in red lines, including windows and a door, on a photo of an actual multi-story building.

Additions and ADUs in Williamson County typically range from $75,000–$250,000+, depending on size and finishes. Smaller garage conversions may take 2–3 months, while detached ADUs often require 4–6 months.

What’s Possible With Your Addition/ADU?

Modern backyard with a green lawn, outdoor seating, and a black painted house with large windows, a patio, and a sliding door at sunset.
Room under renovation with drywall, a ladder, paint bucket, paint roller, and cardboard boxes.
A construction worker on a roof in a backyard, building a new extension with wooden framing, with neighboring houses and green trees in the background.

FAQs

  • We design and build second‑story expansions, room additions (such as larger kitchens or living rooms), garage conversions, in‑law suites and detached accessory dwelling units (ADUs).

  • Timelines vary: room additions may take 3–5 months, while second‑story additions or detached ADUs can take 6–9 months, depending on design complexity and permitting. We provide a detailed schedule before construction begins.

  • Additions and ADUs typically require building, structural, electrical, plumbing and sometimes zoning permits. We handle all permit applications and inspections.

  • Yes. We select materials and architectural details that complement your existing home so the addition looks seamless.

  • We can discuss potential return on investment and connect you with lenders who specialize in home construction and remodeling loans

  • It depends on the scale and location of the addition. For smaller room additions you can often remain at home; larger second‑story projects may require temporary relocation during certain phases.

  • An accessory dwelling unit (ADU) is a secondary housing structure on your property, such as a garage apartment or detached cottage or casita. ADUs are ideal for multi‑generational living, rental income or guest accommodations.

  • Adding square footage typically increases the appraised value and property taxes. We can provide resources to help you estimate the impact and plan accordingly.

  • Our design takes into account existing HVAC, electrical and plumbing systems. We integrate new systems seamlessly to ensure efficiency and balance across the entire home.

  • Costs depend on size, design, finishes and site conditions. We provide a detailed estimate after assessing your property and discussing your goals.

Need more living space?

Contact Metro Custom Builders to discuss your home addition or ADU project and explore how we can expand your home to fit your lifestyle.

Two people working at a round table with a laptop, smartphone, notebook, and a cup of coffee. A small potted plant is in the center. They are seated near a window with sunlight.