Property possibility reportConfirmed report

Your Property's Possibilities, Clearly Mapped

21011 Runnymede St Canoga Park 91303

Prepared August 7, 2026

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

Subject property overview
Existing building

775

Zoning

R1-1

Lot area · sq ft

6501

Backyard depth · ft

67

Rear lot width · ft

50

Backyard area · sq ft

3332

Perimeter · ft

360

Possibility 01 · Extra units

Detached Accessory Dwelling Unit

Conceptually feasible

The mapped geometry supports 4 preliminary detached ADU concepts. Final survey, zoning, fire access, utilities, structural design, and permit review remain required.

800 sq ft ADU Rental Income

UnitLow monthlyHigh monthly
Existing main house
0 bedroom · 775 sq ft
$1,730/month$2,120/month
Detached ADU · 1 bedroom
1 bedroom · 800 sq ft
$1,590/month$1,990/month
Total potential gross rent$3,320/month
$39,840/year
$4,110/month
$49,320/year

RentCast long-term rent range with exact-ZIP comparable context. Low and high monthly scenarios are shown instead of one midpoint. Gross potential only; excludes vacancy, utilities, management, taxes, insurance, repairs, financing, and legal or permit restrictions.

1,200 sq ft ADU Rental Income

UnitLow monthlyHigh monthly
Existing main house
0 bedroom · 775 sq ft
$1,730/month$2,120/month
Detached ADU · 2 bedrooms
2 bedroom · 1,200 sq ft
$2,180/month$2,890/month
Total potential gross rent$3,910/month
$46,920/year
$5,010/month
$60,120/year

RentCast long-term rent range with exact-ZIP comparable context. Low and high monthly scenarios are shown instead of one midpoint. Gross potential only; excludes vacancy, utilities, management, taxes, insurance, repairs, financing, and legal or permit restrictions.

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

The 22 by 36 ft building footprint with its 3 by 22 ft exterior stair fits the preliminary mapped backyard envelope. Final feasibility still requires official SB-9 eligibility, zoning, ADU, building, and permit review.

The combined building is detached from the existing main house. Because the upper ADU is stacked over the proposed SB-9 primary unit in the same building, the ADU is attached to that proposed primary unit.

SB-9 + Upper ADU Rental Income

UnitLow monthlyHigh monthly
Existing main house
0 bedroom · 775 sq ft
$1,730/month$2,120/month
Lower-floor SB-9 unit · 1 bedroom
1 bedroom · 792 sq ft
$1,590/month$1,990/month
Upper-floor ADU · 1 bedroom
1 bedroom · 792 sq ft
$1,590/month$1,990/month
Total potential gross rent$4,910/month
$58,920/year
$6,100/month
$73,200/year

RentCast long-term rent range with exact-ZIP comparable context. Low and high monthly scenarios are shown instead of one midpoint. Gross potential only; excludes vacancy, utilities, management, taxes, insurance, repairs, financing, and legal or permit restrictions.

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

The zoning-based screening leaves 2,150 sq ft of potential addition area. A mapped rear attachment is tested separately in the report.

Existing Property Rental Income

UnitLow monthlyHigh monthly
Existing main house
0 bedroom · 775 sq ft
$1,730/month$2,120/month
Total potential gross rent$1,730/month
$20,760/year
$2,120/month
$25,440/year

RentCast long-term rent range with exact-ZIP comparable context. Low and high monthly scenarios are shown instead of one midpoint. Gross potential only; excludes vacancy, utilities, management, taxes, insurance, repairs, financing, and legal or permit restrictions.

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.

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Next step

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