Room Additions and Great-Room Expansions in Brentwood

Every Brentwood addition starts with arithmetic about the lot. Our estimating desk pulls the zoning designation, the parcel dimensions, and the recorded square footage of the existing house, then calculates how much residential floor area remains. Flat R1 parcels work against the 45 percent limit. Parcels inside the city's mapped Hillside Area work against slope bands, where steeper ground yields less allowable area. Front, side, and rear setbacks fix the buildable footprint. Easements, protected trees, and the reach of the existing foundation narrow it further. We deliver that feasibility read before you commission a full architectural set, so the design begins inside the envelope the city will approve. When the numbers refuse the addition you had in mind, we say so early and show you what the lot will carry.

Indoor-outdoor living in Brentwood is a structural exercise. Removing a rear wall for a multi-panel sliding or pocketing door transfers roof load to a header and a moment frame, which drives new footings and often a deeper foundation than the original house carries. Our engineers size that assembly before the first demolition. Flush thresholds need a drainage plan, a recessed track, and a hardscape slope that moves water away from the sill. Ceiling planes rarely align between an original house and a new volume, so we resolve the transition in the framing, never with trim. Mechanical loads change when a room grows and glazes, so we resize the system for the new volume instead of extending the old ducts into it.

Most great-room additions in Brentwood take the kitchen with them. Running both as one scope keeps plumbing, gas, electrical, and structural work on a single permit set, and it puts one crew on site instead of two contractors sequencing around each other. Cabinetry, appliances, stone, and specialty glazing carry long lead times, so our estimating desk locks selections during plan check while the city reviews the drawings. A temporary kitchen goes in before demolition, with a working sink, refrigerator, and induction surface inside a protected zone. Your project lead publishes a stage schedule tied to named milestones, so you know the week the slab pours, the week the door assembly lands, and the week finishes begin.

Brentwood housing stock runs from prewar Traditional and Colonial Revival through postwar Ranch and mid-century post-and-beam. An addition reads as original when roof pitch, eave depth, fascia profile, window sightlines, and stucco texture carry across the seam. Our field team matches sand float and smooth troweled finishes with sample panels approved on site before any wall gets coated. Wood windows get matched by profile and muntin pattern, never by nearest catalog equivalent. On post-and-beam houses we hold the beam module and the glazing rhythm, since a mismatched bay stays visible from the street for the life of the house. Inside, base, casing, and plaster texture carry through the transition room to room.

We carry the project through plan check, corrections, and inspections. The submittal includes structural calculations, Title 24 energy compliance, and the floor area worksheet the city requires. Most of our clients stay in the house while we build. Our crews set dust walls with negative air at the work boundary, protect floors and stair treads, and mask the path from the entry to the work zone. Tools leave the driveway at the end of each day and the site gets swept. Deliveries stage in phases so neighbor driveways and the street stay clear. Your project lead holds one line of communication, so questions about schedule, selections, and access reach a single person.

Build And Decor Construction holds CSLB license #1113888, Class B General Building and Class C-33 Painting and Decorating, in the name of license holder Sebastian Moreno Rivera. We are fully insured and have completed more than 400 projects. Clients rate our work 5.0 stars on average across 88 reviews. Ratings current as of August 2026. Every project carries a one-year workmanship warranty. We take on select Brentwood projects each year so our field team stays on the jobs it starts. The on-site estimate is free. Call (949) 558-9738, visit buildanddecorconstruction.com, or reach our office at 8033 Sunset Blvd #336, Los Angeles, CA 90046.