Looking for an addition contractor in Los Altos Hills, CA? Describe your project once and up to three addition contractors who work in Los Altos Hills and Santa Clara County get back to you with a quote. It's free and there is no obligation.
Los Altos Hills is home to about 8,435 people (2024 Census Bureau estimate), a stable community (−0.9% since 2020). With 930 people per sq mi, it is a semi-rural area. Growing families here often add space instead of moving.
Los Altos Hills at a glance
- Population (Census Bureau estimate, 2024)
- 8,435 (−0.9% since 2020)
- Rank in California
- 387th of 482 cities and towns
- Land area
- 9.1 sq mi
- Population density
- 930 people per sq mi (semi-rural)
- Type
- Town (Los Altos Hills town)
- Main county
- Santa Clara County
What to check before hiring in Los Altos Hills
- Zoning: check Los Altos Hills's setbacks, lot coverage and height limits first.
- License and permit: in California, additions are built by licensed contractors under a permit.
- Structure: second stories need an engineer to check the existing house.
- Price drivers: size, foundation, roof tie-in, plumbing and finishes.
Useful official resources
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ICC: International Code Council
Official information and guidance.
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NAHB
Official information and guidance.
Services available in Los Altos Hills
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Room addition
Ground-floor addition with foundation, framing, roof and finishes.
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Second-story addition
New floor over the existing house, with structural engineering.
Frequently asked questions in Los Altos Hills
How much does an addition cost in Los Altos Hills, CA?
It depends on size, foundation and finishes. Describe your project: contractors who serve Los Altos Hills reply with a quote.
How long does it take?
Often a few months, plus design and permits.
Does an addition raise property taxes?
Usually, since it increases the assessed value.
Which addition contractors will contact me?
Up to three independent addition contractors who serve Los Altos Hills and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.