Updated: Aug 16, 2025
Location and Projects
Address
6633 MOKELUMNE AVENUE, Oakland, CA, 94605
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Mastin William Duffy Jr Architect
Mastin William Duffy Jr, 6633 Mokelumne Ave, Oakland, CA holds a Architect license according to the California license board.
Their BuildZoom score of 91 ranks in the top 37% of 336,931 California licensed contractors.
Their license was verified as active when we last checked. If you are thinking of hiring Mastin William Duffy Jr, we recommend double-checking their license status with the license board and using our bidding system to get competitive quotes.
Mastin William Duffy Jr Services
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Mastin William Duffy Jr Contact Information
Address: 6633 MOKELUMNE AVENUE, Oakland, CA 94605
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Building Permits by Mastin William Duffy Jr
This is a sample of this contractor's permits. Click here to access their complete permit history.
Fire damage repairs second unit addition gable to roof and seismic. need address assignment before permit can be issued
Valuation:
$650,000
Permit #:
B2012-01557
Status:
Closed Complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Addition 315sqft & remodel. expand footprint of building. electrical mechanical & plumbing
Valuation:
$90,000
Permit #:
B2013-05349
Status:
Issued
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Remodel for (n) bathroom to replace (e) darkroom
Valuation:
$12,000
Permit #:
B2015-05659
Status:
Issued
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Partial foundation replacement
Valuation:
$15,000
Permit #:
B2013-01457
Status:
Issued
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
796sq.ft. 2nd story addition permit closed 6-27-03 sbb
Valuation:
$200,000
Permit #:
B2001-00529
Status:
Closed Complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
2nd floor addition @ rear of house & interior remodel
Valuation:
$175,000
Permit #:
B2003-00260
Status:
Closed Complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Conversion of accessory structure to habitable space
Valuation:
$2,000
Permit #:
B2003-00261
Status:
Closed Complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Adding electrical and mechanical to existing building
Valuation:
$18,354
Permit #:
B1992-01522
Status:
Closed Expired
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
New deck & hot tub on south side of house
Valuation:
$7,755
Permit #:
B1992-00056
Status:
Closed Complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
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Mastin William Duffy Jr License info
Verified License
| License # | C12743 |
| Status | Active |
| State | California |
| Type | Architect |
- BuildZoom verified this license was active as of August 2025.
Verify this license's status for Mastin William Duffy Jr at the California Architect License Board.
This is a sample of licensing data; click here to access a complete history.
91
BuildZoom Score
7
Permits
- Building permit records show that Mastin William Duffy Jr has worked on 7 permitted projects.
Mastin William Duffy Jr Employees
MJ
Mastin William Duffy Jr
Owner