Bay Area Home Additions Designed Around the Way You Live
Design by M&M helps Bay Area homeowners create more functional living space through carefully planned home additions. As a design-build company, we guide your project from early planning and design through permits and construction, helping your addition feel natural, well-built, and connected to the home you already love.
Serving the entire Bay Area
Years
Projects
Our Room Addition Services
Our custom room additions are designed around the unique needs of each homeowner and the existing layout of their home. No two houses are the same, so we take the time to understand how you live, what’s missing, and what your property can support before any plans are drawn.
As a professional home design and construction team, we create design solutions and innovative layouts that make the most of your space — whether that means building out, building up, or reworking how rooms connect. Every addition is engineered to fit seamlessly with your existing home, matching its structure, style, and flow so the new space feels original to the house rather than added on.
From the first concept through final construction, we manage the full design-build process so your addition is thoughtfully planned, well-built, and made to last. We specialize in:
Bedroom Additions
Add more sleeping capacity to the family or guests.
Dining Room Additions
Increase or develop classy eating and entertaining areas.
Family Room Additions
Make living spaces in the middle comfortable and cohesive.
Game Room Additions
Add game rooms to have fun and recreation zones.
Home Office Additions
Special work areas to get work done.
Living Room Additions
More welcoming spaces to have in day-to-day life.
Bathroom Additions
Additional bathrooms as an addition to enhance convenience.
Kitchen Additions
increases or redesigns kitchen area to cook and hold meetings.
Mudroom Additions
These are practical entryways that are used to control clutter and storage.
Master suite Additions
Private, lavish retreats combined with your house.
Sunroom Additions
Well-lit areas of recreation and relaxation.
Laundry Room Additions
Roomy and neat areas to do laundry.
Schedule Your Free Consultation
Thinking about adding more space to your Bay Area home? Tell us a little about your project and our team will reach out to schedule a free consultation.
Whether you are planning a room addition, second-story addition, primary suite, family room expansion, or a larger home improvement project, we can help you understand what may be possible for your property.
During your consultation, we’ll discuss your goals, answer your initial questions, and help you think through the next steps for design, planning, permits, and construction.
No pressure. Just a professional conversation to help you start with more clarity.
License number #1082131
Area We Serve: San Francisco | Palo Alto | Menlo Park | Atherton | Mountain View | Sunnyvale | Los Altos Hills | Belmont | Redwood City | San Mateo | Pacifica | Hillsborough | San Carlos | Woodside | Portola Valley | Saratoga | Los Gatos | Cupertino | San Jose | Santa Clara | Daly City | San Bruno | Millbrae | Burlingame | Los Altos | Campbell | Fremont | Milpitas | Brisbane |foster City
Expand Your Living Space With a Room Addition
When your home no longer fits the way you live, a room addition is one of the smartest ways to expand your living space without leaving the neighborhood you love. As an experienced home addition contractor serving the Bay Area, Design by M&M helps homeowners create custom home additions that feel like a natural part of the home — not an afterthought tacked onto the side.
Room additions can take many forms, from a primary suite or family room to a second-story expansion that adds space without using up your lot. Whatever direction makes sense for your property, the result should do more than add square footage — it should improve how your home functions day to day. That starts with thoughtful design and careful planning around your existing structure, your lot, and how you actually plan to use the new space.
As a design-build company, we manage the entire process under one roof — design, permitting, and construction — so you’re never coordinating between separate architects, designers, and contractors. The result is a smoother project, clearer communication, and a finished addition built to last.
Why Choose Design & Construction by M&M
A successful room extension takes more than construction skill — it takes careful planning, hands-on building experience, and precision at every stage.
As a design-build company, Design & Construction by M&M brings design and construction together under one roof, so your project stays coordinated from the first plan through the final detail. Our team handles the permits, manages the schedule, and pays close attention to the details that matter — including the seamless integration of your new space with the existing home, so the addition looks and feels like it was always there.
It’s this combination of experience, project management, and craftsmanship that homeowners trust us to deliver.
Homeowners trust us for:
- Bespoke designs that suit their lifestyle.
- Local codes and permitting Knowledge.
- Smooth appearance into your house design.
- Sustainable workmanship and construction quality.
- Quality materials and competent construction personnel.
About us
Design & Construction by M&M is a Bay Area design-build company serving homeowners throughout the Bay Area and across California. With years of experience in room addition and home renovation, we specialize in creating functional, beautiful spaces that fit the way each homeowner lives — backed by custom designs tailored to your home, your lot, and your goals.
As a design-build team, we bring planning, design, and construction together under one roof, which keeps your project coordinated and your communication clear from start to finish. Whether you’re adding a room, expanding your home, or reworking an outdated layout, we guide you through every step with quality craftsmanship and genuine care for the result. Your satisfaction drives everything we do, and we’re committed to going the extra mile on every project.
Our Room Addition Process
Each project is done in a systematic manner to allow proper execution and quality.