Room Additions and Second-Story Additions in Los Angeles

Most of the additions we build fall into four shapes.

Bedroom and bathroom bump-outs. A single room pushed off the back or the side of the house. This is the smallest addition that still needs a full permit, a new foundation, and a clean tie-in to the existing roof and walls. Families use it to add a fourth bedroom, a guest room, or a second full bath.

Primary suites. A bedroom, a bathroom, and a walk-in closet built as one wing. The plumbing run, the window placement, and the door swing off the existing hallway decide whether the suite feels like part of the house or like a room stuck on the back of it. We settle those details in design, not in the field.

Second-story additions. New living space stacked over the existing footprint. This is the answer on tight lots where the yard is already spoken for and the setbacks leave nowhere to grow sideways.

Family rooms and great-room expansions. Opening the back of the house into a larger living space, often combined with a new kitchen layout and wide glass to the yard. These jobs usually involve removing bearing walls, so a beam and post design comes with them.

Any of these can run alongside a remodel of the existing kitchen or baths. Doing both under one permit and one crew keeps the finishes consistent and the house apart only once.

Feasibility. We walk the property with you, measure the house, and review the zoning and permit history on the parcel. Setbacks, lot coverage, and height limits define the envelope you are allowed to build in. Hillside lots, overlay zones, and older nonconforming structures narrow it further. You get a straight answer on what the lot allows before you spend money on design.

Design and engineering. Architectural drawings fix the floor plan, the roof lines, and the window layout. A structural engineer sizes the beams, the shear walls, and the footings, then draws the load path from the new roof down to soil. Energy compliance documents ride with the plan set.

Plan check and permits. Plans go to the building department with jurisdiction over your address. In the City of Los Angeles that is LADBS. Corrections come back, we answer them, and the permit issues. This phase runs on the department's clock.

Foundation. Excavation, forms, rebar, and a new footing doweled into the existing foundation. The inspector signs the steel before any concrete is placed.

Framing and tie-in. The tie-in is where additions succeed or fail. We match floor height, cut the existing roof back to a clean line, weave new framing into old, and hold the wall planes true so the finished house reads as one building.

Rough trades. Plumbing, electrical, HVAC, then insulation. Every stage is inspected before it gets covered.

Finishes and final. Drywall, texture, paint, flooring, trim, fixtures. The final inspection closes the permit and the new square footage lands on the property record.

You get a written scope and a stage schedule before work starts, and an update at every inspection.

A second story is a different job than a ground-floor addition, and the difference starts below the floor.

The existing house gets evaluated first. An engineer looks at the foundation, the first-floor framing, and the shear walls to see what the structure can carry. Older houses often need footing work, new shear panels, or hold-downs at the first floor before anything goes on top. That work is invisible in the finished house, and it is what the engineering is for.

The stair takes space downstairs. A second story needs an access run, and that run eats floor area on the first floor. We locate it early, because moving a stair after framing is a rebuild.

You are often living in the house while we build. We stage the job to keep a working kitchen and at least one bath running, seal off the work zone with temporary walls and dust barriers, and set a daily cleanup standard the crew holds to. You know each week what gets loud and when.

Weather protection is planned, not improvised. Removing the roof is the exposed moment of the entire project. We schedule that phase against the forecast, dry-in the new framing fast, and keep temporary covering and pumps on site. A house open to the sky is a house we do not leave unattended.

Drywall and paint stay in-house. Our license carries the Class C-33 painting and decorating classification alongside the Class B general building classification, so the finish work is ours to answer for.

Matching matters more on an addition than on new construction. Your existing walls carry a texture: orange peel, knockdown, skip trowel, or smooth. We match it, then feather the transition so the seam between old and new disappears. Outside, we match stucco texture and color, or repaint the full elevation when the existing color has faded, so the addition never reads as a patch bolted onto the house.

Paint runs the same order every time: patch, caulk, sand, prime, sand, two finish coats. Raking light off a west wall shows every shortcut, so we set a work light against the wall and walk it before we call a room finished. The project lead signs off on the finish before the punch list closes.

Additions and ADUs solve different problems.

An addition grows the house you live in. It shares the roof, the kitchen, the address, and the utilities, and the new square footage counts toward the main dwelling. That is what you want when the family needs a fourth bedroom, a primary suite, or a real family room.

An ADU is a separate dwelling with its own kitchen, bath, and entrance. It fits when you want rental income, housing for a parent or an adult child, or a workspace that stays independent of the house. A garage conversion often delivers that second unit faster than new construction, since the slab and the walls are already standing.

Choose the addition when the space has to connect to your daily living. Choose the ADU when the space has to stand on its own. Some properties support both, and we will tell you which order makes sense on your lot. Our ADU and garage conversion page covers that path in detail.

We build additions across Los Angeles: the Westside, Hollywood and mid-city, and the northeast LA neighborhoods. We also work the Orange County coastal cities.

Build And Decor Construction is licensed and insured. Clients rate our work 5.0 stars on average across 88 reviews. Ratings current as of August 2026. More than 400 projects are behind us, and every one of them carries a one-year workmanship warranty.

The first step is a free on-site estimate. We walk the property, listen to what you want out of the space, and tell you what the lot and the structure will allow. You leave that conversation knowing what is possible, whether or not you build with us.

Call (949) 558-9738 or email sebastian@buildanddecorconstruction.com.

Build And Decor Construction, 8033 Sunset Blvd #336, Los Angeles, CA 90046.