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ActiveSingle Family

$7,995,000

1080 Westridge Dr, Portola Valley 94028

Beds5
Baths4
Sqft3,425
DOM23
No Photos Available

AddressIntel AI Briefing

The optimal play is teardown-and-mansionize to substitute the mid-sized residence with a sprawling contemporary estate. The property's generous acreage provides an ideal canvas for custom luxury design in Portola Valley.

Property Permit History

No permit history found directly associated with this property's address.

Recent Neighborhood Remodeling (Portola Valley)

Parcel & Zoning Info

APN077012090
Official Lot Sqft110,631
Zoning CodeNO DATA ASSIGNED
SB 9 StatusLikely · up to 4 units
Unlock Pathways
Ministerial ADU Ministerial SB 9 Density Bonus
Entitlement RiskLow (0/100)

ADU Potential

Feasibility Score99/100
Max ADU Units2 (ADU + JADU)
Est. ADU Size1,200 sqft
Existing Coverage3.1%

Standard lot · ~319 ft frontage × 447 ft deep, typical proportions for a detached ADU behind or beside the home.

Screening heuristic based on lot size, existing coverage, lot orientation, and hazard overlays. CA ADU law is ministerial statewide; verify max size, setbacks, and JADU owner-occupancy with the local planning dept.

Redevelopment Potential

Redevelopment Score78/100
ClassExpansion room
FAR Utilization8% of allowed
Buildable Headroom+40,828 sqft

Meaningful unused floor-area headroom under current zoning, room to add square footage. Zoning allows roughly 44,253 sqft of gross floor area on this lot.

Screening estimate comparing existing living area to the city's single-family floor-area limit. City sets no explicit FAR (or is not individually curated); allowable area is a conservative estimate. Source: conservative default (0.40 FAR — city not individually curated) (as of 2026-06-30). Verify FAR, coverage, setbacks, and height with the local planning dept.

Hazard Snapshot

Flood Zone

X
Area of minimal flood hazard.

Fire Severity

Moderate
Elevated fire risk; impacts insurance cost and building materials.

Liquefaction

No
Not in a mapped liquefaction zone.

Fault Zone

No
Not in a mapped Alquist-Priolo fault zone.

Not a substitute for a Natural Hazard Disclosure (NHD) report. Zones reflect available GIS data and may not cover all localities. Liquefaction and fault flags: modified from California Geological Survey, Web Service of Official Maps of Alquist-Priolo Earthquake Fault Zones and Web Service of Official Maps of Seismic Hazard Zones (2025).

Nearby Public Schools

Elementary School

Ormondale Elementary

Portola Valley Elementary

0.7 miles away
Middle School

Corte Madera

Portola Valley Elementary

1.6 miles away
High School

Woodside High

Sequoia Union High

3.8 miles away

School boundaries are subject to change. Nearest school distance does not guarantee enrollment eligibility. Check with the local district. Data provided by CDE.

Proprietary Intelligence

Market Heat Index

11/100

Based on recent sales velocity and local demand in 94028.

Flippability Score

60/100

Measures neighborhood renovation density vs. recent permits on this property.

Bidding War Prob.

1%

Likelihood of multiple offers based on local list-to-sale ratios and DOM.

Proforma ROI Calculator

Back-of-the-napkin deal analysis across development strategies.

Median of 12 recent single-family sales in Portola Valley (94028): $1,692/sqft, plus 5% because new houses sold at a median 1.07x their comps across 239 real rebuilds. Sized within 25% of the 5,100 sqft build, because smaller houses sell for more per foot and pricing a rebuild off them overstates resale.

Commission, transfer tax and closing. Deducted from resale before profit, so the ROI below is net of the exit rather than gross.

Interest on the purchase price for the whole project plus half the build budget, since construction draws ramp up. The default is 7% over 33 months, the median purchase-to-sale time of 239 real Peninsula and South Bay rebuilds. Set the rate to 0 for a cash purchase, or use your own lender's terms.

Hard Costs$2,805,000
New Build5,100 sqft
Total Capital Required$10,975,000
Estimated Resale (ARV)$9,062,700
Cost of Sale (5%)-$453,135
Carry (33mo @ 7%)-$1,825,863
Net Proceeds$6,783,703

Projected Profit

-$4,191,298
-38.2% ROI

Warning: Project is mathematically underwater.

Recent Comparables (Portola Valley 94028)

Sized to the modelled 5,100 sqft build: sales within 25% of it. Smaller houses sell for more per foot, so pricing a rebuild off them overstates resale.

155 Grove Dr

Sold
$14,850,000
Sold: 2026-10-20
Lot: 54,343
Sqft: 5195
$/Sqft: $2,859

40 Hillbrook Dr

Sold
$7,000,000
Sold: 2026-10-02
Lot: 43,561
Sqft: 5282
$/Sqft: $1,325

2 Buck Meadow Dr

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$7,250,000
Sold: 2026-10-02
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Sqft: 4100
$/Sqft: $1,768

2 Franciscan Rdg

Sold
$4,950,000
Sold: 2026-08-28
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Sqft: 3887
$/Sqft: $1,273

281 Georgia Ln

Sold
$14,500,000
Sold: 2026-08-28
Lot: 188,179
Sqft: 5120
$/Sqft: $2,832

241 Georgia Ln

Sold
$14,500,000
Sold: 2026-08-28
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Sqft: 5686
$/Sqft: $2,550

90 Hayfields Rd

Sold
$3,945,000
Sold: 2026-06-17
Lot: 72,177
Sqft: 5390
$/Sqft: $732

120 Deer Meadow Ln

Sold
$8,400,000
Sold: 2026-06-03
Lot: 114,116
Sqft: 5200
$/Sqft: $1,615

56 Hillbrook Dr

Sold
$9,495,000
Sold: 2026-05-13
Lot: 43,556
Sqft: 4885
$/Sqft: $1,944

340 Willowbrook Dr

Sold
$5,900,000
Sold: 2026-04-24
Lot: 43,560
Sqft: 4250
$/Sqft: $1,388

2 Horseshoe Bnd

Sold
$5,100,000
Sold: 2026-03-12
Lot: 22,015
Sqft: 4640
$/Sqft: $1,099

40 Sioux Way

Sold
$16,350,000
Sold: 2026-02-17
Lot: 73,181
Sqft: 4695
$/Sqft: $3,482