Looking for a spray foam installer in Foster City, CA? Describe your project once and up to three spray foam installers who work in Foster City and San Mateo County get back to you with a quote. It's free and there is no obligation.
Foster City is home to about 32,657 people (2024 Census Bureau estimate), a shrinking community (−3.4% since 2020). With 8,623 people per sq mi, it is a densely built-up area. Hot summers, cold winters and leaky older homes make air sealing a priority here.
Foster City at a glance
- Population (Census Bureau estimate, 2024)
- 32,657 (−3.4% since 2020)
- Rank in California
- 229th of 482 cities and towns
- Land area
- 3.8 sq mi
- Population density
- 8,623 people per sq mi (densely built-up)
- Type
- City (Foster City city)
- Main county
- San Mateo County
What to check before hiring in Foster City
- Training: ask about applicator training and safety practices.
- Code: in California, the energy and residential codes set R-values and barrier requirements.
- Rebates: utilities sometimes rebate insulation upgrades.
- Price drivers: area, foam type, thickness and prep.
Useful official resources
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U.S. Department of Energy: insulation
Official information and guidance.
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Spray Polyurethane Foam Alliance
Official information and guidance.
Services available in Foster City
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Attic spray foam
Spray foam on the roof deck or attic floor, often to create a conditioned attic.
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Walls, rim joists and crawl spaces
Spray foam in open walls, rim joists, basements or crawl spaces.
Frequently asked questions in Foster City
How much does spray foam cost in Foster City, CA?
It depends on area, foam type and thickness. Describe your project: installers who serve Foster City reply with a quote.
How long does installation take?
Often a day for a typical attic, plus curing time.
Can foam go over old insulation?
Usually old material is removed first; ask the installer.
Which spray foam installers will contact me?
Up to three independent spray foam installers who serve Foster City 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.