Expand Without Moving

Room Additions in Tarzana

Permitted master-suite additions, second-story builds, family rooms and bump-outs. Finished to match your existing home, across Tarzana and the San Fernando Valley area.

Room additions, master suites and second-story builds in Tarzana and the LA area. A room addition is one of the smartest ways to gain space. Make room for a growing family, add a home office or guest room, or get the square footage you need without the cost and hassle of moving.

We design and permit primary-suite additions, second-story builds, family rooms, sunrooms and bump-outs throughout Tarzana and the wider Los Angeles area. Every addition is fully permitted, structurally engineered, and finished to match your existing home so the new space feels like it has always been there.

One in-house team handles design, permits, structural, MEP rough-ins, framing, finishes and inspections — see our six-step process.

What it is

ADUs — Accessory Dwelling Units

Independent secondary living spaces on the same lot as a primary home — backyard cottages, garage conversions, in-law suites and detached studios — each with their own kitchen, bathroom and entry. California’s permissive ADU laws make these the fastest way to add usable square footage and long-term rental income on most residential lots.

Detached 1- or 2-bedroom backyard cottages, 400–1,200 sq ft
Garage-to-living-space conversions
Junior ADUs (JADU) carved out of the primary home
Two-story ADUs where lot coverage allows

What it is

Room Additions

Expansions of the existing home rather than separate units — bumping out a kitchen, adding a master suite, popping the roof for a second story, attaching a sunroom or family room. Footprint, structural work, MEP and finish carpentry are handled in-place so the new space flows naturally with what’s already there.

Primary-suite additions with walk-in closet + en-suite
Second-story builds over a single-story home
Family-room, sunroom and great-room bump-outs
Home-office and bonus-room expansions

Our process

We handle the full path end-to-end: design + structural engineering, City of LA / county permitting, foundation, framing, MEP rough-in, drywall, finish carpentry and final inspections. Typical timelines once permits issue: 12–20 weeks for a detached ADU, 8–14 weeks for a room addition, depending on scope, structural complexity and inspector schedule.

Independent units

ADUs — Accessory Dwelling Units

Detached cottages, garage conversions and JADUs — each with their own kitchen, bath and entry.

Modern Oak ADUDetached oak-clad backyard cottage with floor-to-ceiling glass and concrete patio

White Plaster Suite ADUDetached stucco ADU with sliding glass wall, bedroom suite and outdoor kitchenette

Garden Cottage ADUDetached stucco guest cottage with shed roof framed by drought-tolerant landscaping

Open-Plan ADU InteriorLight-oak kitchen island and living room under beamed ceiling with steel garden doors

In-place expansions

Room Additions

Master suites, family rooms, sunrooms and second-story builds attached to the existing home.

Second-Story AdditionSecond-story addition with vertical wood cladding and floor-to-ceiling upper windows

Primary Suite AdditionVaulted primary-bedroom addition with beamed ceiling, plaster fireplace and arched window seat

Formal Living AdditionFront sitting room with stone fireplace, window seat, crown molding and white boucle seating

Primary Bedroom AdditionCoffered-ceiling primary bedroom with plantation shutters and dark walnut furnishings

Family Room AdditionFamily room with custom walnut media wall, built-in shelving and tall flanking windows

Great Room Bump-OutVaulted living + dining great-room opening to kitchen with black-frame casement windows

Living Room Bump-OutTray ceiling, brass chandelier, window-seat bump-out, wall-mounted TV on walnut console

Sitting Room AdditionCozy addition with curved bay window, masonry fireplace and floating walnut reading shelf

Guest Bedroom AdditionGuest bedroom with black-frame windows over hillside, cube storage and accent seating

What it is

ADUs — Accessory Dwelling Units

Detached 1- or 2-bedroom backyard cottages, 400–1,200 sq ft
Garage-to-living-space conversions
Junior ADUs (JADU) carved out of the primary home
Two-story ADUs where lot coverage allows

What it is

Room additions

Expansions of the existing home rather than separate units — bumping out a kitchen, adding a master suite, popping the roof for a second story, attaching a sunroom or family room.

Primary-suite additions with walk-in closet + en-suite
Second-story builds over a single-story home
Family-room, sunroom and great-room bump-outs
Home-office and bonus-room expansions

Our process

We handle design + structural engineering, City of LA / county permitting, foundation, framing, MEP, drywall, finish carpentry and final inspections. Typical timelines: 12–20 weeks for a detached ADU, 8–14 weeks for a room addition.

Room Addition FAQs

What homeowners ask before adding square footage in Tarzana and LA.

What's the difference between a room addition and an ADU?

A room addition expands your existing home — a primary suite, second story, family room or bump-out that flows with the current floor plan. An ADU is a separate, self-contained unit with its own kitchen, bath and entry. We build both.

How long does a room addition take?

Most room additions run 8–14 weeks from permit-ready to final inspection. Second-story additions take longer than single-room bump-outs, and city plan-check times are the biggest variable.

What does a room addition cost in Tarzana?

Cost depends on square footage, whether it's single-story or a second-story build, finish level and structural work required. We give a written line-item estimate after the design phase so there are no surprises.

Do I need an architect?

For most room additions we cover the design in-house and bring in a licensed architect / structural engineer where the city plan-check requires stamped drawings. Either way it's coordinated through us.

Can a second-story addition work on my existing foundation?

Sometimes — it depends on the original construction, soils report and seismic requirements. We commission the structural evaluation first so you know whether the existing foundation works, needs retrofit, or requires a different approach.

Recent Work

Built. Finished. Loved.

A look at recent kitchen, bathroom, room-addition and whole-home transformations from our Tarzana design-build team.

Open-plan whole-home remodel in modern California style — Master in Design, Tarzana CA

Designer Visualizations

Ready to start your project?

Tell us about it — no obligation, no pressure. We respond within one business day.

Every room addition we build in Tarzana is permitted through LADBS (or your local jurisdiction), with Master in Design managing the full process. Title 24, CALGreen, and structural plans all in scope.