$8,950,000
27 Catalpa Dr, Atherton 94027
Size check
The listing's square footage against the county assessor's record and the permits on file.
The listing and the county record agree within 10%.
What can explain a difference
- Space built without a permit.
- Permitted work the assessor has not recorded yet.
- An ADU, a finished basement or a converted garage counted in one figure and not the other.
- Different measuring. Listing agents and the assessor often measure the same house differently.
Our Atherton permit record starts in 2023. Work permitted before then will not appear above.
AddressIntel AI Briefing
This massive Atherton lot offers an exceptional opportunity for a premium teardown-and-mansionize play, given the current low footprint of the 1961 structure. With no environmental hazards to restrict construction, developers can maximize the allowable square footage to match nearby ultra-luxury comps. Utilizing a stealth density approach by adding an ADU and JADU can further optimize the estate's total yield.
Property Permit History
Recent Neighborhood Remodeling (Atherton)
Parcel & Zoning Info
ADU Potential
Wide & shallow · ~236 ft frontage × 275 ft deep, limited depth, an ADU likely sits beside the house rather than behind it.
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
Small, older home using a low share of the allowable building envelope on a sizable lot, a scrape-and-rebuild or major-expansion play. Zoning allows roughly 7,314 sqft of gross floor area on this lot.
Screening estimate comparing existing living area to the city's single-family floor-area limit. FAR rule curated from current municipal code. Source: Atherton Muni Code 17.32.040 (R-1A), district from Town zoning GIS (as of 2026-08-24). Verify FAR, coverage, setbacks, and height with the local planning dept.
Hazard Snapshot
Flood Zone
Fire Severity
Liquefaction
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
Encinal Elementary
Menlo Park City Elementary
Cesar Chavez Ravenswood Middle
Ravenswood City Elementary
Menlo-Atherton High
Sequoia Union High
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
57/100
Based on recent sales velocity and local demand in 94027.
Flippability Score
85/100
Measures neighborhood renovation density vs. recent permits on this property.
Bidding War Prob.
46%
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.
Zoning allows roughly 7,314 sqft on this lot, and the default builds to that envelope. The FAR figure is a discretionary-review trigger, not a hard cap.
Median of 12 recent single-family sales in Atherton (94027): $2,274/sqft, plus 5% because new houses sold at a median 1.07x their comps across 239 real rebuilds. Sized within 25% of the 7,300 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.
Projected Profit
Warning: Margin is tight for the construction risk.
Recent Comparables (Atherton 94027)
Sized to the modelled 7,300 sqft build: sales within 25% of it. Smaller houses sell for more per foot, so pricing a rebuild off them overstates resale.