Updated: Mar 25, 2026
Location and Projects
Address
490 CHADBOURNE RD SUITE A145, Fairfield, CA, 94534
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Keystone Construction Group Inc
Based in Fairfield, CA, Keystone Construction Group Inc provides general contracting services for residential and commercial projects across Solano County and the surrounding area. The company’s portfolio includes kitchen and bathroom remodels, room additions, and custom home construction. Keystone Construction Group Inc also undertakes commercial tenant improvements, including office and retail buildouts. Serving property owners and business clients, the company manages projects from pre-construction planning through completion. With five years of experience, Keystone Construction Group Inc coordinates all phases of the construction process, working with architects, designers, and subcontractors to deliver finished spaces that meet client specifications. The company utilizes current building materials and adheres to code requirements for both new construction and remodels.
Keystone Construction Group Inc Services
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Keystone Construction Group Inc Contact Information
Phone Number: (707) 365-8367
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Address: 490 CHADBOURNE RD SUITE A145, Fairfield, CA 94534
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Keystone Construction Group Inc Fairfield
Quality
102
89th percentile
Pro tip:
We generally recommend hiring a contractor with a score higher than 95.
Keystone Construction Group Inc has a BuildZoom score of 102, which places them above 89% of 336,931 contractors in California.
Activity
|
5 projects
|
2025 |
|
2 projects
|
2024 |
|
3 projects
|
2023 |
Our building permit records indicate that Keystone Construction Group Inc has worked on at least
10.0 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 Keystone Construction Group Inc mostly works on
home addition
projects.
Pricing
|
1 project
|
$20k-$50k |
|
1 project
|
$50k-$100k |
|
3 projects
|
$100k-$250k |
|
2 projects
|
$250k-$500k |
The typical size of their permits is approximately $126,479. 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 Keystone Construction Group Inc
This is a sample of this contractor's permits. Click here to access their complete permit history.
Residential: full review - additions adu accessory structures pools remodel demolish generators and
2025-06-20
New detached accessory dwelling living - 1200 sq ft garage - 536 sq ft covered porches - sq footages to come
Valuation:
$301,691
Permit #:
BLD25-00533
Status:
issued
Fee:
$12,945
Permit Type:
Accessory
Building Type:
N/A
Scope of work: -new detached 1-story 694 sqft adu with slab-on-grade foundation -adu to include: 2 bedrooms 2 bathrooms kitchen/living w/d w.h. -includes prefabricated roof trusses
Valuation:
$114,975
Permit #:
2025 093276 RS
Status:
issued
Fee:
$2,343
Permit Type:
2nd unit added
Building Type:
N/A
748sqft detached adu
Valuation:
$224,700
Permit #:
RES25-0390
Status:
filed
Fee:
$5,704
Permit Type:
Residentl
Building Type:
N/A
Evt17-05047 rebuild single family dwelling 1 280 (sf) deck 228 (sf) 8.1kw roof mount photovoltaic system w 26kwh ess 2017 sonoma complex fire complete red new construction of a detached 1280 sf raised foundation single family home
Valuation:
N/A
Permit #:
BLD25-1950
Status:
issued
Fee:
$5,614
Permit Type:
N/A
Building Type:
N/A
Scope of work: -construct detached in rear -adu to contain kitchen bathroom laundry bedroom living area new 100amp subpanel revision s3 11/2/20: -converting adu to a manufactured adu -sq ft changing to 611 sq ft -2 bedrooms 1 bathroom and kitch. **revision** ld 5/12 -floor plan reversal -foundation remains the same ***revision *** jc 5/27/21 -upgrade 200amp panel to 400 amp addition s... see more
Valuation:
$90,542
Permit #:
2019 143494 RS
Status:
final
Fee:
N/A
Permit Type:
2nd unit added
Building Type:
N/A
564 sf hud/hcd manufact: adu pge#120464999 for 400a service
Valuation:
N/A
Permit #:
BLDG2021-0046
Status:
final
Fee:
$7,601
Permit Type:
Detached_101
Building Type:
N/A
534 sq.ft. manufactured adu - 1 bedroom - 1 full bathroom - laundry closed - fau in closet - tank water heater
Valuation:
$200,000
Permit #:
B21-0127
Status:
final
Fee:
$9,886
Permit Type:
N/A
Building Type:
N/A
Epc - existing garage conversion to 1 bed 1 bathroom 371 sq ft to adu with a10 sq ft utility room. carbon monoxide & smoke alarms required. reference crc sections r315 & r314 water conserving fixtures are required to be installed throughout this residence per sb 407 (note: residences built after january 1 1994 are exempt)
Valuation:
$29,680
Permit #:
RES-2417980
Status:
issued
Fee:
$2,774
Permit Type:
N/A
Building Type:
N/A
Fire damage rebuild (steele fire): replacement adu
Valuation:
$80,000
Permit #:
BR21-02470-RPL
Status:
final
Fee:
$5,196
Permit Type:
N/A
Building Type:
N/A
New 1041 sft adu. detached adu (manufactured home on permanent foundation)
Valuation:
N/A
Permit #:
DEV21-0743
Status:
final
Fee:
$4,348
Permit Type:
N/A
Building Type:
N/A
New hud-hcd approved manufactured home on permanent foundation as adu (1200 sf)
Valuation:
N/A
Permit #:
BLD21-3747
Status:
issued
Fee:
$9,723
Permit Type:
N/A
Building Type:
N/A
1173 sf hud/hcd approved manufactured unit to be installed on permanent foundation as a detached adu
Valuation:
N/A
Permit #:
BLD21-3507
Status:
issued
Fee:
$9,856
Permit Type:
N/A
Building Type:
N/A
1, 050 sf hud/hcd approved manufactured unit to be installed on permanent foundation as a detached adu
Valuation:
N/A
Permit #:
BLD21-3342
Status:
withdrawn
Fee:
$9,837
Permit Type:
N/A
Building Type:
N/A
Scope of work to include: - construction of (n) 507 sq ft detached hud approved adu
Valuation:
$62,087
Permit #:
2021 014574 RS
Status:
issued
Fee:
N/A
Permit Type:
2nd unit added
Building Type:
N/A
Building 749 sqft detached adu
Valuation:
$294,600
Permit #:
BRES2024-0404
Status:
canceled
Fee:
$12,689
Permit Type:
Addition
Building Type:
N/A
Second dwelling
Valuation:
$59,760
Permit #:
BR21-01402-NEW
Status:
expired
Fee:
$5,763
Permit Type:
N/A
Building Type:
N/A
Detached manufactured adu 1200 sf
Valuation:
N/A
Permit #:
DEV21-1984
Status:
triage
Fee:
$2,450
Permit Type:
N/A
Building Type:
N/A
New 749 sf 2-bed prefab unit hud approved
Valuation:
N/A
Permit #:
B2021-0374
Status:
final
Fee:
$9,649
Permit Type:
Second unit-detached
Building Type:
N/A
Scope of work: - construct a (n) 748 sq ft detached 1 sty all electric adu at rear lot of (e) main residence - adu to include 2 bedrooms bathroom kitchen/living w/d & 8 sq ft utility closet w w.h
Valuation:
$126,479
Permit #:
2025 100170 RS
Status:
issued
Fee:
$2,825
Permit Type:
2nd unit added
Building Type:
N/A
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Keystone Construction Group Inc License info
Verified License
| License # | 1054973 |
| Status | Active |
| State | California |
| Type | General Building, Manufactured Housing |
| Business Type | Corporation |
- BuildZoom verified this license was active as of March 2026.
Verify this license's status for Keystone Construction Group Inc at the California Contractors State License Board.
This is a sample of licensing data; click here to access a complete history.
102
BuildZoom Score
Bonded
| Bonded Agent | Western Surety Company |
| Bond Value | $15,000 |
19
Permits
- Building permit records show that Keystone Construction Group Inc has worked on 19 permitted projects.
Keystone Construction Group Inc Employees
BN
Benjamin Edward Nelson
Rmo / Ceo / Pres
MN
Mindy Lew Nelson
Officer