Redondo Beach Home Addition — Coastal Expansions Built to Last

A Redondo Beach home addition has the same marine-grade specification problem as every other coastal South Bay build, plus the Coastal Commission CDP review layer on west-of-PCH properties, plus the structural complexity of pushing a 1950s Cape Cod or 1970s ranch into a second-story or rear-wing configuration. The homes here are appreciating into the $1.5M-$3M range, the lots are small (5,000-7,500 square feet), and the additions are usually master suites, family rooms with ocean view capture, second-story bedroom additions, or full rear wings that combine multiple programs. NPLD has designed across the South Bay coastal corridor since 2016 and held a CSLB general contractor license since 2023, with over 200 LA builds completed. Our Redondo Beach additions run $200K-$560K over a 12-22 month build window, with the Redondo Beach Building Department, Coastal Commission CDP, marine-grade exterior specification, and structural engineering for second-story work handled inside the scope.

What a Redondo Beach Home Addition Costs in 2026

Pricing breaks by scope. A rear-yard family room or breakfast room addition with ocean-view capture, 300-450 square feet, runs $200K-$310K. A master suite addition with bath and walk-in closet, 450-700 square feet, runs $300K-$430K. A second-story addition over an existing single-story footprint, 700-1,000 square feet, runs $400K-$560K because the existing foundation, shear walls, and roof structure have to be re-engineered, and the marine-grade exterior is doubled across two stories. Geotech (when needed near the bluffs or on the Hillside areas), structural engineering, and Title 24 add $22K-$55K. Architectural design fees, when handled by NPLD's design arm, run 8-12 percent of construction cost. Coastal Commission CDP, when triggered, adds $10K-$35K and 12-24 weeks.

Coastal Commission CDP and the West-of-PCH Question

Properties west of Pacific Coast Highway are in Coastal Commission jurisdiction. Additions that add floor area, change the building envelope, or affect designated view corridors trigger a full discretionary CDP review with public hearing. The review process runs 12-24 weeks, sometimes longer when the project pulls public comment. We file the CDP application at the schematic stage on west-of-PCH properties so the scope adjusts before architectural and structural fees are committed. East of PCH (the Avenues, the inland sections), no CDP applies, and the addition runs through the Redondo Beach Building Department alone. The CDP review is the single biggest schedule variable on a west-of-PCH addition.

Second-Story Additions, Existing Foundations, and the Structural Reality

The 1950s Cape Cods and 1960s-1970s ranch homes that define Redondo Beach were not designed for second-story additions. The existing perimeter footing, often 12-18 inches deep with minimal rebar, has to be augmented or replaced under the new load. The existing first-floor shear walls have to be retrofitted. The existing roof has to come off, with a temporary roof during the framing phase. Structural engineering at schematic design tells us the exact scope. Foundation augmentation on a second-story addition adds $55K-$160K to the build. A full perimeter footing replacement, on the homes where the existing footing fails the engineer's review, adds $90K-$220K. We do a soils report ($3K-$8K) on lots near the bluff edge or on the historic dune areas because the soil conditions affect the foundation design.

• Redondo Beach Building Dept permit and plan check: $9K-$20K
• Coastal Commission CDP (full discretionary review, west of PCH): $10K-$35K, 12-24 weeks
• Structural engineering (second-story or large rear wing): $18K-$48K
• Foundation augmentation or replacement: $55K-$220K depending on existing condition
• Marine-grade exterior across two stories: $35K-$85K additional

Marine-Grade Exterior and the Two-Story Cost

The marine-grade exterior specification that protects a single-story addition costs more when applied across a second-story footprint, because the surface area roughly doubles. Fiberglass-framed windows, fiber-cement siding, 316 stainless fasteners and flashing, and marine-grade exterior light fixtures across a 1,000 square foot second story add $35K-$85K against a generic inland build. The build pays back over the next 20-30 years because the corrosion replacement cycle that affects standard exteriors at 5-8 years does not happen. We do not cut marine-grade specification to save short-term cost on a coastal addition; the standard inland build does not survive the salt air at the Strand-adjacent and Esplanade-facing addresses.

How We Sequence a 12-22 Month Redondo Beach Addition

Month one through three is site survey, buildable-footprint analysis, soils report if needed, and schematic design with a CDP preview if west of PCH. Month three through seven is design development, structural engineering, Title 24, and permit filing at the Redondo Beach Building Department, with the CDP application filed in parallel when applicable. Month seven through twelve is plan check and CDP review. Month twelve through twenty-two is construction: foundation, framing, marine-grade exterior, MEP rough-in, drywall and finish, millwork, and final inspections. The household stays in the front portion of the home through most of the build, with sealed dust barriers, separate HVAC zoning, and trade access through a side gate. Friday written updates against the schedule. Single point of accountability through 22 months.