Updated: Dec 19, 2025
Location and Projects
Address
1275 FOLSOM STREET, San Francisco, CA, 94103
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Duff, William Seaman Jr Architect
Duff, William Seaman Jr, 1275 Folsom St, San Francisco, CA holds a Architect license and 2 other licenses according to the Arizona license board.
Their BuildZoom score of 104 ranks in the top 9% of 336,931 California licensed contractors.
Their license was verified as active when we last checked. If you are thinking of hiring Duff, William Seaman Jr, we recommend double-checking their license status with the license board and using our project planner to get competitive quotes.
Duff, William Seaman Jr Services
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Duff, William Seaman Jr Contact Information
Phone Number: (415) 371-0900
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Address: 1275 FOLSOM STREET, San Francisco, CA 94103
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Duff, William Seaman Jr San Francisco
Quality
104
91st percentile
Pro tip:
We generally recommend hiring a contractor with a score higher than 95.
Duff, William Seaman Jr has a BuildZoom score of 104, which places them above 91% of 336,931 contractors in California.
Activity
|
3 projects
|
2025 |
|
9 projects
|
2024 |
|
9 projects
|
2023 |
Our building permit records indicate that Duff, William Seaman Jr has worked on at least
21.0 projects over the past 3 years.
This is an overview of this contractor's activity. Click here to access our complete licensing and building permit database.
This is an overview of this contractor's activity. Click here to access our complete licensing and building permit database.
Experience
|
7 projects
|
Home Additions |
|
4 projects
|
Commercial Renovations |
Analyzing permits over the last 4 years shows that Duff, William Seaman Jr mostly works on
home addition
and commercial renovation
projects.
Pricing
|
5 projects
|
< $5k |
|
1 project
|
$5k-$20k |
|
2 projects
|
$20k-$50k |
|
4 projects
|
$50k-$100k |
|
3 projects
|
$100k-$250k |
|
2 projects
|
$500k-$1mil |
|
2 projects
|
$1mil+ |
The typical size of their permits is approximately $50,000. This graph shows the distribution of these job values.
Pro tip:
For more details about their pricing, check out their recent activity to see how much they have charged for different types of work.
Building Permits by Duff, William Seaman Jr
This is a sample of this contractor's permits. Click here to access their complete permit history.
New interior remodel. bathroom relocation at 1/f new windows and door openings facing backyard. infill of open areas under cantilevered room at 1/f. demolition of (e) trellis structure in backyard. new kitchen & pantry @ 2nd fl
Valuation:
$500,000
Permit #:
202303224164
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Conversion of (e) unconditioned pool enclosure building to new family room with small addition on connector to main house; remodel of existing kitchen and pantry with new appliances and plumbing fixtures
Valuation:
$1,100,000
Permit #:
202109138255
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Mou proj# 19-0263. mayor's ed# 17-02. project located @ parcel a consist of construction & develoment of 6-story ground up speculative class office building of roughly 356 000 sq ft (over 6 fl & 1 basement) & subteranean parking. limited building amenity spaces included as part of c&s construction
Valuation:
$75,600,000
Permit #:
201908300403
Status:
approved
Fee:
N/A
Permit Type:
N/A
Building Type:
10 - office
Front building - interior remodel: laundry and playroom replace spiral stairs to garage w (n) elevator. lower sill and replace (e) front window with a door to create access to garage roof terrace. reinforce (e) garage roof framing to support (n) raised tile deck surface
Valuation:
$500,000
Permit #:
202208311635
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Interior remodel, infill portion of(e)deck with (n) conditioned space @ second floor only and(n)roof over conditioned space demolish(e)garage bay @ ground fl level only (n) garage door & wall to align w/(e)facade above addition @ north west corner of building. remove(e)deck at rear 13"-11"portion
Valuation:
$600,000
Permit #:
201710131186
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
28 - 2 family dwe...
1st floor: interior adjustments to create nw guest room & relocate office room nw exterior double door & double-hung windows at rear facade in nw guest rm: nw exterior door & casement windw at rear facade in office rm; 2nd fl: removal of extg wall between kitchen & family rm;
Valuation:
$25,000
Permit #:
202404049303
Status:
filed
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Interior kitchen remodel at unit 1. remodel consists of new kithcen layout new locations for plumbing fixtures relocation of 1 bathroom and reduction to powder room. no changes on exterior. exterior work under separate pa 202109138303
Valuation:
$80,000
Permit #:
202110049743
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
28 - 2 family dwe...
Administrative permit to document revision to 202205254948(original permit) & 202305097417(rev to original) to an additional of passenger elevator and shaft to replace a demolished elevator and shaft to rename elevator room to machine room on (a2.21)
Valuation:
$1
Permit #:
202402065358
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
10 - office
23rd fl: tenant improvement of an (e) office space including (n) interior non-structural partitions and finishes lighting & millwork. fire sprinkler under separate permit
Valuation:
$1,355,480
Permit #:
202103257304
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
10 - office
Addition of roof deck & retractable skylight new reconfigured patio @ (e) rear yard minoe excavation/foundation replacement @ mud room. new sliding door 1/f rear new window @ front & rear replace (e) window & swing door @ living room east facade w/sliding door new interior stair to replace (e)
Valuation:
$700,000
Permit #:
202111051940
Status:
filed
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Addition of roof deck & retractable skylight new reconfigured patio @ (e) rear yard minoe excavation/foundation replacement @ mud room. new sliding door 1/f rear new window @ front & rear replace (e) window & swing door @ living room east facade w/sliding door new interior stair to replace (e)
Valuation:
$700,000
Permit #:
202111051940
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Rear bldg: interior remodel of e cottage structure including kitchen and bathroom. reframe e floor at kitchen to increase interior head height. new deck structure hot tub and oudoor kitchen adjacent to cottage
Valuation:
$150,000
Permit #:
202302141972
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Tenant improvement. ground floor convert retail store to office space. structural mechanical plumbing electrical upgrades
Valuation:
$999,839
Permit #:
202204081865
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
10 - office
Voluntary structural upgrade at garage. no change to maximum path of travel of egress path. upgrade at garage
Valuation:
$50,000
Permit #:
202304216195
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Horizontal addition. proj incl interior remodel & rear horizontal addition of the (3)(e) floor levels. residence expanded to rear yard setback within the additon of 10'-0 height permitted obstruction into rear yard @ ground fl. replace in-kind of (e) windows & all related electrical mechanical & plumbing work
Valuation:
$610,660
Permit #:
201801098195
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Addition of new mezzanine and stair in existing building for new restrooms for future dining space. expansion of existing terrace. existing community to be renovated
Valuation:
$500,000
Permit #:
B21-1101
Status:
triage
Fee:
$3,022
Permit Type:
N/A
Building Type:
Restaurants
Addition of new mezzanine and stair in existing building for new restrooms for future dining space. expansion of existing terrace. existing community to be renovated
Valuation:
$500,000
Permit #:
PRE21-01345
Status:
filed
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Front building demolish & rebuild (e) concrete footing to expand laundry room on 1st level; excavate and building (n)concrete retaining walls to create (n) storage area at garage level. all work within existing envelope
Valuation:
$50,000
Permit #:
202210124206
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Partial removal of exterior finishes at the northwest corner of the structure to expose water damaged sheathing & framing; replace damaged windows in-kind in affected area as necessary. apply (n) stucco finish to match (e)
Valuation:
$50,000
Permit #:
202207269321
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
Revision to pa 202111051940 relocation of (e) posts at the 2nd fl rear deck to the edge of the deck. no other modifications to the (e) deck
Valuation:
$1,000
Permit #:
202502271228
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
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Verified License
BuildZoom confirmed this contractor's license
Duff, William Seaman Jr License info
Verified License
| License # | 39199 |
| Status | Active |
| State | Arizona |
| Type | Architect |
- BuildZoom verified this license was active as of June 2025.
Verify this license's status for Duff, William Seaman Jr at the Arizona Board of Technical Registration.
This is a sample of licensing data; click here to access a complete history.
License Not Verified
| License # | 9460-5 |
| Status | Active |
| State | Wisconsin |
| Type | Architect |
- When BuildZoom last verified this license, it had an expiration date of July, 2016. Check the current license status of Duff, William Seaman Jr with the Wisconsin Department of Safety and Professional Services
This is a sample of licensing data; click here to access a complete history.
Verified License
| License # | C26772 |
| Status | Active |
| State | California |
| Type | Architect |
- BuildZoom has not verified this license since June, 2025.
Verify this license's status for Duff, William Seaman Jr at the California Architect License Board.
This is a sample of licensing data; click here to access a complete history.
104
BuildZoom Score
53
Permits
- Building permit records show that Duff, William Seaman Jr has worked on 53 permitted projects.
Duff, William Seaman Jr Employees
DS
Duff, William S
Owner
DJ
Duff, William Seaman Jr
Owner