Updated: Feb 05, 2026
Location and Projects
Address
928 SOUTH NORFOLK, San Mateo, CA, 94401
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Gilbert O Sullivan Construction
Based in San Mateo, Gilbert O Sullivan Construction has served residential clients throughout the area for the past 20 years. The company specializes in a range of home improvement and remodeling services, with portfolio projects showing kitchen renovations, bathroom updates, and custom carpentry work. Gilbert O Sullivan Construction is experienced in both interior and exterior renovations, offering expertise with room additions, deck building, and structural upgrades tailored for single-family homes. Projects managed by the company often emphasize functional design adapted to the needs of Bay Area homeowners. Serving neighborhoods across San Mateo and surrounding cities, the firm is equipped to oversee all aspects of construction, from initial planning through to completion. The principal, Gilbert O Sullivan, is directly involved in day-to-day operations and project oversight.
Gilbert O Sullivan Construction Services
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Gilbert O Sullivan Construction Contact Information
Phone Number: (650) 630-0411
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Address: 928 SOUTH NORFOLK, San Mateo, CA 94401
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Gilbert O Sullivan Construction San Mateo
Quality
103
90th percentile
Pro tip:
We generally recommend hiring a contractor with a score higher than 95.
Gilbert O Sullivan Construction has a BuildZoom score of 103, which places them above 90% of 336,931 contractors in California.
Activity
|
4 projects
|
2025 |
|
1 project
|
2024 |
|
1 project
|
2023 |
Our building permit records indicate that Gilbert O Sullivan Construction has worked on at least
6.0 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
|
3 projects
|
Home Additions |
Analyzing permits over the last 4 years shows that Gilbert O Sullivan Construction mostly works on
home addition
projects.
Pricing
|
1 project
|
$5k-$20k |
|
2 projects
|
$50k-$100k |
|
2 projects
|
$100k-$250k |
|
1 project
|
$250k-$500k |
The typical size of their permits is approximately $200,000. 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 Gilbert O Sullivan Construction
This is a sample of this contractor's permits. Click here to access their complete permit history.
**2019 codes apply** attached adu of 801sf- convert a portion of 1st floor attached garage into an adu and (e) 2nd floor family room of main residence. refer to permit bd-2023-287740 for main single family dwelling remodel and addition
Valuation:
$354,074
Permit #:
BD-2023-290708
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
**2019 codes apply** single family dwelling addition of 347.11sf and remodel of 575sf to main residence. 1st floor addition of 375sf and remodel of to include a new great room enlarge kitchen with a new pantry remodel and reconfigure the study room into a bedroom. 2nd floor addition of 199sf to enlarge the (e) master bathroom. remodel garage to a 1-car garage and addition of 32.58f to... see more
Valuation:
$286,141
Permit #:
BD-2023-287740
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Single family (alteration/repair) - kitchen & bathroom remodel (flat)
2025-01-21
Kitchen remodel: r&r existing cabinets and drywall. new insulation where needed electrical upgrade from 100 amps to 200 amps located at the rear of the house
Valuation:
$65,000
Permit #:
BD-2025-296907
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Remodel existing 2nd floor bathroom plus renovation of bedroom & closet electrical and plumbing upgrades included
Valuation:
$99,026
Permit #:
BD-2025-296991
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Replace existing garage door with bi-fold door which opens completely. addition drywell. this project includes expanding the driveway and adding a curb cut. revision 1 - the door design was revised to a wood door with glass instead of the glass bifold door in the permit. (iss 10.14.25)
Valuation:
$14,000
Permit #:
BD-2025-298146
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
New attached adu of 678sf total. convert portion of garage 463sf and addition of 215sf enclose covered patio into the adu. remodel existing full bathroom in adu and building a new wall between adu and garage. remove stairs and fill-in wall opening of stairs leading up to the main dwelling from the lower level
Valuation:
$75,000
Permit #:
BD-2020-276107
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
1)add rooms down-retreat with two bedrooms two w/c a full bathroom and laundry room on 1st floor; 2) reconfigure interior layout on 2nd floor per plan; 3) addition one full bathroom on 2nd floor. to comply w/his nov201463971 dated 4/3/2014
Valuation:
$90,000
Permit #:
201811135651
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
27 - 1 family dwe...
R e m o d e l k i t c h e n b a t h l a u n d r y r o o m | r e m o d e l k i t c h e n b a t h l a u n d r y r o o m
Valuation:
$135,000
Permit #:
B22-0071
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Single family dwelling 1st floor addition of 792sf for (n) nook (n) kitchen (n) foyer (n) master bedroom bathroom and walk-in closet. (e) kitchen to be removed to expand dining room. (e) covered porch to be removed to expand living room. change location of closet in (e) bedroom. install (n) electrical throughout and replace (e) furnace and water heater. (n) gas insert total remodel ar... see more
Valuation:
$250,000
Permit #:
BD-2017-263694
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
I n t e r i o r r e m o d e l
Valuation:
$200,000
Permit #:
B22-0489
Status:
issued
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Residential single story addition (203 sf) remodel (827 sf) creating new attached adu (411 sf) a tankless water heater and an electric service upgrade to 200 amps in the same location. ***adu has an approved address of 3628 evergreen ar***
Valuation:
$99,685
Permit #:
17000-03103
Status:
final
Fee:
$7,186
Permit Type:
N/A
Building Type:
N/A
Renewal: pp20191127566: same work scope: new plumbing work including: guttes (3) toilets (1) kitchen (3) bathrooms
Valuation:
N/A
Permit #:
PP20210402116
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Single family dwelling 1st floor addition of 792sf for (n) nook (n) kitchen (n) foyer (n) master bedroom bathroom and walk-in closet. (e) kitchen to be removed to expand dining room. (e) covered porch to be removed to expand living room. change location of closet in (e) bedroom. install (n) electrical throughout and replace (e) furnace and water heater. (n) gas insert total remodel ar... see more
Valuation:
$7,000
Permit #:
FS-2018-265923
Status:
final
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
Expand existing pool house guest room and existing garage. expand and enclose existing breezeway to create new mudroom. - this permit also includes reroof of single family residential home and attached garage to install cdx plywood 30# felt underlayment and new preseidential tl composition shingles. inspections to include tear off in progress and final
Valuation:
$80,000
Permit #:
BLD2018-00033
Status:
final
Fee:
$8,216
Permit Type:
Addition
Building Type:
N/A
Remove interior wall in laundry room no exterior changes
Valuation:
N/A
Permit #:
BLDG2022-0466
Status:
triage
Fee:
$494
Permit Type:
Alteration_434
Building Type:
N/A
New electrical whole house new 200amp panel. new plugs lights switches ckts
Valuation:
N/A
Permit #:
E201911275843
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
N/A
17000-03103: revision to lower floor level of adu revise shear wall length at line 5 revise structural details at columns and headers
Valuation:
N/A
Permit #:
18REV-00254
Status:
issued
Fee:
$121
Permit Type:
N/A
Building Type:
N/A
Unit #103: interior remodel to reconfigure floor plan to addition one bedroom in the unit. new finsihes, addition new full bathroom and remodel (e) bathroom. relocate kitchen per plan. comply with nov 201402751. maher n/a
Valuation:
$77,000
Permit #:
201411121257
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
24 - apartments
Unit #102: converting existing dining room into a bedroom by adding a door bathroom remodel- plumbing fixtures rearrangement and new bathroom finishes new washer/dryer in an existing closet (unit on 2nd story); maher n/a
Valuation:
$16,000
Permit #:
201407020346
Status:
complete
Fee:
N/A
Permit Type:
N/A
Building Type:
24 - apartments
Over 50% addition/remodel -on partial existing foundation and basement reconstruct and enlarge main level addition second floor and loft 5bedrms 5.5 bths resubmittal # 1 - jpb - 02/28/2014 - as requested by planning - lower the height of the attic space to 6'6 resubmittal #2 rmm 3/27/14 - new sheet 1a ( bmps) in response to planning comments resubmittal #3 rmm 4/8/14 - new sheets 1 1a... see more
Valuation:
$25,012
Permit #:
BLD2013-02048
Status:
final
Fee:
$40,485
Permit Type:
N/A
Building Type:
N/A
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Gilbert O Sullivan Construction License info
Verified License
| License # | 803045 |
| Status | Active |
| State | California |
| Type | General Building |
| Business Type | Sole Ownership |
- BuildZoom verified this license was active as of February 2026.
Verify this license's status for Gilbert O Sullivan Construction at the California Contractors State License Board.
This is a sample of licensing data; click here to access a complete history.
103
BuildZoom Score
Bonded
| Bonded Agent | American Contractors Indemnity Company |
| Bond Value | $15,000 |
Insured
| Workers Comp Provider | State Compensation Insurance Fund |
36
Permits
- Building permit records show that Gilbert O Sullivan Construction has worked on 36 permitted projects.
Gilbert O Sullivan Construction Employees
GS
Gilbert John O Sullivan
Owner
GO
Gilbert John O'sullivan
Sole Owner