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Property possibility reportConfirmed report

Your Property's Possibilities, Clearly Mapped

9742 Farralone Ave Chatsworth 91311

Prepared August 7, 2026

Detached ADU · Detached SB-9 + ADU · Main-house Addition

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Subject property overview
Existing building

3418

Zoning

RA-1

Lot area · sq ft

16253

Backyard depth · ft

60

Rear lot width · ft

125

Backyard area · sq ft

7568

Perimeter · ft

510

Hybrid property map
Hybrid property map
Transportation map
Transportation map
Street view
Street view
ZIMAS property map
ZIMAS property map
Possibility 01 · Extra units

Detached Accessory Dwelling Unit

Conceptually feasible

Backyard living opportunity

A private new home may fit in the backyard.

We identified 4 practical concepts to compare. A site survey and City review will confirm the final plan.

Maximum estimated rental potential

800 sq ft ADU Rental Income

Existing main house0 bedrooms · 3,418 sq ftUp to $8,290/month
Detached ADU · 1 bedroom1 bedroom · 800 sq ftUp to $2,280/month
Total potential gross rentUp to $10,570/month$126,840/year before expenses

Preliminary market estimate. Final rent depends on the completed design, property condition, and current market.

Maximum estimated rental potential

1,200 sq ft ADU Rental Income

Existing main house0 bedrooms · 3,418 sq ftUp to $8,290/month
Detached ADU · 2 bedrooms2 bedrooms · 1,200 sq ftUp to $2,770/month
Total potential gross rentUp to $11,060/month$132,720/year before expenses

Preliminary market estimate. Final rent depends on the completed design, property condition, and current market.

One-story detached ADU concept

Option A · One-story detached ADU

A compact first-floor concept sized to the usable yard. Construction is estimated at $215–$235 per square foot.

Two-story detached ADU concept

Option B · Two-story detached ADU

A smaller footprint preserves more yard while providing two floors. Construction is estimated at $225–$245 per square foot.

Preliminary project cost estimateDetached ADU
Architectural design + permit drawings$4–$6 / sq ft
Structural design + engineering$1–$2.50 / sq ft
Title 24 energy compliance$300 flat
Survey + site plan$1,800–$2,500
Permit coordination$1,500 / permit
Plan check + permit allowance$2,000–$20,000
Design + permit range$11,600–$34,500
Combined planning range$341,600–$484,500
Completed project exampleHatteras One-Bedroom ADU Conversion
View project →
Possibility 02 · Extra units

Detached SB-9 + ADU

Preliminary fit available

Two-home income opportunity

Two private living spaces may fit in one detached building.

The concept places one home on each floor. Survey, eligibility, design, and City review will confirm the final plan.

Maximum estimated rental potential

SB-9 + Upper ADU Rental Income

Existing main house0 bedrooms · 3,418 sq ftUp to $8,290/month
Lower-floor SB-9 unit · 1 bedroom1 bedroom · 792 sq ftUp to $2,280/month
Upper-floor ADU · 1 bedroom1 bedroom · 792 sq ftUp to $2,280/month
Total potential gross rentUp to $12,850/month$154,200/year before expenses

Preliminary market estimate. Final rent depends on the completed design, property condition, and current market.

Detached SB-9 and ADU concept map

Stacked two-unit concept

Lower floor: SB-9 unit. Upper floor: ADU. The mapped footprint adapts to the actual open yard instead of forcing one fixed rectangle.

Concept configuration

500–800 sq ft per floor

Two stories · two units · larger building side aligned with the shorter lot dimension where geometry permits.

Two-story construction$225–$245 / sq ft
Completed project exampleSAF Duplex Van Nuys
View project →
Possibility 03 · Main house

Main House Addition

First + second-floor concepts

More space for the main home

The existing home may support a connected addition.

First-floor and upper-floor directions can be compared before the final design is selected.

Maximum estimated rental potential

Existing Property Rental Income

Existing main house0 bedrooms · 3,418 sq ftUp to $8,290/month
Total potential gross rentUp to $8,290/month$99,480/year before expenses

Preliminary market estimate. Final rent depends on the completed design, property condition, and current market.

First-floor house addition concept

Option A · First-floor attached addition

The footprint is shaped around available backyard space and connected directly to the existing main house.

Second-floor house addition concept

Option B · Second-floor addition

A second-floor option uses the existing building footprint and can combine with a smaller connected first-floor remainder.

Preliminary project cost estimateMain house addition
Potential addition area1,615 sq ft
Architectural + permit drawings$4–$6 / sq ft
Structural engineering$1–$2.50 / sq ft
Survey + site plan$1,800–$2,500
Permit coordination$1,500 / permit
Plan check + permit allowance$2,000–$20,000
Planning note

Construction and design totals are preliminary allowances. Survey, zoning, structural capacity, setbacks, and agency review remain required.

Preliminary combined range$341,600–$484,500
Completed project exampleTop of Bel Air · Addition Project
View project →
Client-ready property package

Download the Full Property Possibilities Report

Property facts, mapped concepts, zoning screens, project examples, and preliminary investment ranges in one PDF.

Open Full PDF Report
Next step

Turn a preliminary possibility into a verified design strategy.

Schedule a site review with the 121 Design Build team to confirm the concept, establish the project scope, and prepare the path toward drawings and permits.

info@121designbuild.com(424) 600-110017801 Ventura Blvd, 2nd Floor
Encino, CA 91316121designbuild.com
Schedule a consultation

Bring the report to a design review

We will review the mapped opportunities, identify the required verification, and outline a practical design and permit path.

Request strategy session