Modern white house with a black roof, outdoor seating on a wooden deck, surrounded by a landscaped yard with plants and stone pathway.
Open sliding barn door style doors leading into a cozy indoor space with a black sofa, white cushions, and wall art, with plants and natural light.

Custom Home Additions and ADUs in Pasadena, Glendale, Arcadia, Altadena, San Marino, and Surrounding SoCal Communities

  • Trusted by 50+ local families

  • Exceptional workmanship and materials

  • Specialized teams and experienced trade partners

Upsize Your Home for the Future

As your family’s needs and lifestyle evolve, your home should grow with you. Whether you’re creating a guest suite for in-laws, adding space for entertaining, or expanding for a growing household, Mareci & Steele Construction can help you do it without leaving the neighborhood you love.

Building a room addition or an accessory dwelling unit (ADU) is one of the most effective ways to increase your home’s value and functionality. From garage conversions and backyard cottages to multi-room expansions, we design and build spaces that meet your goals, complement your existing home, and comply with local zoning requirements.

Our team of skilled general contractors delivers beautiful, functional upgrades tailored to your vision and budget with the added potential for rental income in the case of ADUs.

Popular Additions Include:

  • Garage conversions

  • Fully detached additions

  • Room conversions

  • Main floor expansions

  • Second-story additions

  • Room bump-outs

  • Sunrooms

  • Family room extensions

With Mareci & Steele Construction, you get more than extra square footage, you get a seamless extension of your home that’s built to last.

The Leading Room Additions & ADU Builder in Altadena, CA