Home Additions in Mountain View, CA
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No Design Review, Clear Standards
Mountain View has no discretionary design review for single-family homes and does not require notice to neighbors. A Planning permit is needed only for exceptions such as a variance or floor-area exception, a conforming addition to a nonconforming home, exterior changes to a historic home, or lots of 10,000 sq ft or more next to a creek. Those go to the Zoning Administrator, who holds hearings on the second and fourth Wednesdays with mailed notice within 750 feet.
In the R1 zone, floor area ratio is 0.50 minus 0.00001 times the lot area, or 0.40 on lots of 10,000 sq ft or more, and two-story homes are capped at 28 feet with larger second-story setbacks.
Addition Work
Mountain View Addition Thresholds
- Fire sprinklers: required when an addition brings the home to 4,100 sq ft total or doubles its size.
- Public Works review: additions or equivalent remodels of 600 sq ft.
- Green Building Code compliance: additions of 1,000 sq ft or more.
- School fees: new residential area over 500 sq ft, with proof of payment before permit issuance.
- Survey certificate: a wet-signed survey for structures within 6 feet of a property line.
- Heritage trees: any tree 48 inches or more in circumference at 54 inches, or oak, redwood or cedar at 12 inches, needs a removal permit.
- Flood zones: about 12% of the city is in a flood hazard area; work there needs a Flood Development Permit and an Elevation Certificate.
Typical total time for additions and remodels is 3 to 8 months.
City Hall, 500 Castro Street, Mountain View, CA 94041
Building (650) 903-6313 (Fire ext. 0) · Planning (650) 903-6306 · Public Works (650) 903-6311
Public counters Monday to Friday, 8 a.m. to 4 p.m., plus a Virtual Public Counter. All Building, Fire, Planning, Public Works and Heritage Tree applications go through ePermitsMV; building inspections are scheduled there.
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Mountain View Home Additions FAQ
Do additions need design review in Mountain View?
No. Mountain View has no discretionary design review for single-family homes.
When does an addition require sprinklers?
When it brings the home to 4,100 sq ft or doubles its size.
How is floor area calculated?
FAR is 0.50 minus 0.00001 times lot area, or 0.40 on lots of 10,000 sq ft or more.
How long does approval take?
Typically 3 to 8 months total for additions and remodels.