Remodeling and additions in Los Altos & Los Altos Hills

Ranch to two-story in Los Altos

The most common big project we discuss in Los Altos starts with a 1950s single-story ranch on a generous lot: the family wants more bedrooms, and the question is whether to build up or out. Both are possible, but they follow different review paths.

Under the city's design review chapter, rewritten in 2025, a one-story home that stays at or under 20 feet tall, and additions that keep it that way, get staff-level design review. Converting a one-story home to two stories, or building a new two-story home, goes to the Zoning Administrator at a noticed public meeting. Property owners within 300 feet receive mailed notice in advance, a notice is posted on the site, and the decision can be appealed. Before design starts we also check whether your street is in a single-story overlay (R1-S) district, which limits homes to one story.

The review findings focus on how the house sits on its street: following the natural grade with minimal grading, breaking up mass with articulated elements at a human scale, avoiding large blank walls, choosing materials that reduce the perceived height and bulk, and landscaping that gives visual relief. A second story that steps back from the ground-floor walls and keeps the roof lines simple usually reads as smaller from the street.

The construction side matters as much as the approval. A ranch's foundation and framing were sized for one story, so adding a floor means an engineer checks the existing foundation and designs new shear walls and, often, new footings. The stair takes space from the ground floor, the roof comes off during framing, and many families move out for part of the job. A single-story rear addition avoids most of that and stays at staff review, which is why we price both options when they're realistic.

Our part: we measure the existing house, prepare the drawings, coordinate engineering, prepare the design review submittal, respond to staff comments and attend the public meeting with you, then take the approved design through building plan check and schedule the inspections.

Last reviewed: October 2026 · Sources: Los Altos Municipal Code — Chapter 14.77 Design Review (opens in new tab) · Los Altos Municipal Code — Chapter 14.01 (public notice and appeals) (opens in new tab) · Los Altos Municipal Code — Chapter 14.13 R1-S Single-Story Overlay (opens in new tab)