Room Additions in Los Altos, CA
Design by M&M helps Los Altos homeowners expand their living space through carefully planned additions — managing design, permits, and construction from concept to completion.
Home Additions

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.

Second Story Additions
Add a second story to maximize your living space

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.
Home Additions
For many Los Altos households, an addition is the most practical way to stay in a neighborhood they love while gaining the space they need. As an experienced room addition contractor, Design by M&M helps homeowners expand your living space in the way that fits the property best.
Common addition projects we take on in Los Altos include:
- Rear additions — the larger lots common in Los Altos often make extending the back of the home the most natural way to add a family room, larger kitchen, or primary suite
- Second story additions — adding an upper level to a single-story ranch home when preserving yard space matters
- Side additions — expanding into side yard space where setbacks and lot coverage allow
- Primary suite and family room additions — creating the spaces growing households need most
Every addition starts with feasibility. We review your lot, structure, and local requirements first, so the design you fall in love with is one that can actually be built.
Accessory Dwelling Units (ADU)
With spacious lots and strong demand for flexible living space, Los Altos is well suited for ADUs — whether for aging parents, adult children, guests, or rental income. As an experienced ADU builder in Los Altos, Design by M&M guides homeowners through every stage, from confirming what the lot can legally support to final inspection.
We design and build all types of ADUs, including:
- Detached ADUs — standalone backyard units with their own entrance and utilities, a popular fit for larger Los Altos lots
- Attached ADUs — additions connected to the main home with independent living space
- Junior ADUs and in-law suites — smaller conversions within the existing home, ideal for multigenerational living
Before starting an ADU, homeowners need to understand where utilities will connect, how the unit will fit on the lot, and what local and state ADU rules allow. We handle that groundwork so the project moves forward with clarity instead of guesswork.
Garage Conversions
We specialize in turning underused garages into comfortable, fully permitted living space. Serving Los Altos and nearby communities, our team helps homeowners expand what their property can do — without changing the footprint of the home.
Popular garage conversion projects include:
- Converting a garage to an ADU for rental income or family use
- Creating a home office or studio for remote work
- Adding a guest suite or flexible bonus room
Garage conversions often look simple from the outside, but they involve real construction and compliance work: insulation, electrical upgrades, plumbing (for ADU conversions), egress requirements, and city permitting. We manage those details from the start, so the finished space is safe, legal, and built to last.
Design Build
Design by M&M is a design build contractor, which means one team manages your project from concept to completion. Instead of coordinating separate architects, designers, engineers, and builders, you work with a single team responsible for the entire outcome.
Our design-build approach includes:
- Consultation and property review
- Custom designs shaped around your goals, lot, and budget
- Architectural planning and engineering coordination
- Permitting and city approvals
- Construction scheduling and project management
- The build phase, through final walkthrough
This approach keeps design decisions and construction realities connected. Thoughtful design means little if it can’t be built within your budget — and quality construction depends on planning that was realistic from day one. When one team owns both, the process stays clear and accountable.
Home Remodeling
As a remodeling company in Los Altos, we focus on larger renovation projects that improve how a home functions — not just how it looks. Many Los Altos homes still carry their original mid-century layouts: compartmentalized kitchens, smaller bedrooms, and closed-off living areas. Our home remodeling services help homeowners open up those spaces, modernize aging systems, and improve flow throughout the home.
Our remodeling services include:
- Whole house renovation — comprehensive updates to layout, systems, and finishes
- Kitchen remodels — typically as part of larger layout improvements or expansions
- Major renovations — reworking floor plans, removing walls, and modernizing older homes
- Renovation paired with additions — improving the existing home while adding square footage
Our remodeling process follows the same design-build structure as our additions and ADU work: feasibility first, then design, budget alignment, permitting, and construction — all managed by one team with clear communication throughout.
Design in 3 simple steps
Consult & Design
We start with a thorough consultation, creating custom designs tailored to your style and needs.
Expert Construction
Our skilled team manages every detail, from demolition to installation, ensuring precision and quality.
Enjoyment
We complete your project with meticulous attention, ensuring your complete satisfaction and a stunning new kitchen.
Frequently Asked Questions
If you don’t see your question answered here, please don’t hesitate to contact us directly – we’re always happy to help!”
Most room additions take several months from initial design through final construction, depending on project size, design complexity, and city review times. Second story additions and projects requiring structural engineering generally take longer than single-room ground-floor additions. We build permitting into the schedule from the beginning and give you a realistic timeline during your consultation.
Yes. Room additions, ADUs, and garage conversions in Los Altos all require permits and plan review through the city. Los Altos also has lot coverage, floor area, and setback rules that shape what can be built on your property. As a design-build contractor, we prepare the plans, manage submittals, and guide the project through the approval process on your behalf.
Many Los Altos properties have the lot space to build out, which is often simpler and less disruptive than adding a second story. Building up makes sense when preserving yard space is a priority or lot coverage limits are a factor. The right answer depends on your lot, your home's structure, and your goals — and that comparison is exactly what our feasibility and design phase is built to answer.
The biggest cost factors are the size of the addition, structural work required, site conditions, finish level, and whether utilities or the foundation need upgrades. Older Los Altos homes sometimes need electrical, plumbing, or foundation updates as part of an expansion, which is better to identify during planning than mid-construction. We review your property first, then build a budget around what your project actually requires.
A well-built, fully permitted ADU adds usable square footage and flexibility — space for family, guests, or rental income — which many homeowners view as a meaningful long-term investment, particularly in high-value markets like Los Altos. The right ADU depends on your lot, goals, and budget, and we help you weigh those factors before committing to a design.
You don't need finished plans — that's what the design-build process is for. It helps to think about how you want the space to function, a general budget range, and your rough timeline. From there, we review your property, discuss feasibility, and help you understand what is possible before any major decisions are made.