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Find Addition to existing structure builders in Castro Valley

North Point Construction and Restoration, Inc.

5114 Port Chicago Hwy B
New on HomeAdvisorNew on HomeAdvisor
•Approved Pro

North Point Construction and Restoration, Inc.

5114 Port Chicago Hwy B
New on HomeAdvisorNew on HomeAdvisor
•Approved Pro
8 years of experience
Free onsite estimate

At North Point Construction and Restoration, Inc., we pride our company on reliability, great communication, integrity, and quality work that customers can believe in. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business and working with you! 20 years of experience.

At North Point Construction and Restoration, Inc., we pride our company on reliability, great communication, integrity, and quality work that customers can believe in. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business and working with you! 20 years of experience.

Universal Construction Company

161 Martin Place
4.71(
7
)
•Approved Pro

Universal Construction Company

161 Martin Place
4.71(
7
)
•Approved Pro
Customers say: Quick response
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
45 years of experience

We are a locally owned and operated company that values honesty and integrity, and treats your home as if it were our own. We offer a variety of general contractor and home improvement services that are customizable to each individual project. We specialize in additions and bathroom remodels, but also offer a wide range of expertise for a variety of other projects. We pride ourselves on the quality of our work, as well as our commitment to outstanding results. We look forward to building lasting relationships, and guarantee your satisfaction!

"He is very good, communicates well, and he is there when he says he will be and very thorough! I liked doing business with him! He explains everything that he will do before he does the job and he listens to my suggestions."

Marilyn B on June 2019

We are a locally owned and operated company that values honesty and integrity, and treats your home as if it were our own. We offer a variety of general contractor and home improvement services that are customizable to each individual project. We specialize in additions and bathroom remodels, but also offer a wide range of expertise for a variety of other projects. We pride ourselves on the quality of our work, as well as our commitment to outstanding results. We look forward to building lasting relationships, and guarantee your satisfaction!

"He is very good, communicates well, and he is there when he says he will be and very thorough! I liked doing business with him! He explains everything that he will do before he does the job and he listens to my suggestions."

Marilyn B on June 2019

Avatar for Fixit Construction, Inc.

Fixit Construction, Inc.

184 Bowling Green Street
3.00(
1
)
•Approved Pro

Fixit Construction, Inc.

184 Bowling Green Street
3.00(
1
)
•Approved Pro
Customers say: Terrific value
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
11 years of experience

We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business! Book with us online or feel free to give us a call today!

"They were professional and completed the project on time."

Elizabete T on September 2016

We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business! Book with us online or feel free to give us a call today!

"They were professional and completed the project on time."

Elizabete T on September 2016

Avatar for UNITED C CONSTRUCTION, INC

UNITED C CONSTRUCTION, INC

1900 Powell Street Suite 700
5.00(
3
)
•Approved Pro

UNITED C CONSTRUCTION, INC

1900 Powell Street Suite 700
5.00(
3
)
•Approved Pro
Customers say: Quick response
1 years of experience
Free onsite estimate

We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business!

"Updating our home was a dream we have had for years. But finding a good contractor in Bay Area was so difficult, that we almost gave up. We were introduced to United C Construction by our architect(who we also love!) It was exhausting trying to find someone trustworthy and not overpriced. We had luck of working with Osmar which during the project we had clear communication, expectation of setting, professionalism and superior craftsmanship. He walked us through every step of the way, and helped problem solve tough permitting and structural issues in Berkeley!"

Shelby R on September 2024

We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forward to earning your business!

"Updating our home was a dream we have had for years. But finding a good contractor in Bay Area was so difficult, that we almost gave up. We were introduced to United C Construction by our architect(who we also love!) It was exhausting trying to find someone trustworthy and not overpriced. We had luck of working with Osmar which during the project we had clear communication, expectation of setting, professionalism and superior craftsmanship. He walked us through every step of the way, and helped problem solve tough permitting and structural issues in Berkeley!"

Shelby R on September 2024

Ashbury General Contracting and Engineering

40 12th Street
4.50(
2
)
•Approved Pro

Ashbury General Contracting and Engineering

40 12th Street
4.50(
2
)
•Approved Pro
Customers say: Terrific value
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
35 years of experience

Mon-Fri 7a-5pm Fully integrated company. All work is done in-house by employees not sub-contractors. We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forwards to earning your business! Book with us online or feel free to give us a call today!

"Great work for a great price."

Paul H on March 2023

Mon-Fri 7a-5pm Fully integrated company. All work is done in-house by employees not sub-contractors. We pride our company on reliability, great communication, integrity, and quality work. We are experts in our trade and will do our best to keep you as educated as we can on your particular task or project. We look forwards to earning your business! Book with us online or feel free to give us a call today!

"Great work for a great price."

Paul H on March 2023

AM GENERAL CONTRACTOR

2341 W Ave #133
5.00(
2
)
•Approved Pro

AM GENERAL CONTRACTOR

2341 W Ave #133
5.00(
2
)
•Approved Pro
Customers say: Quick response
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
22 years of experience

We take great pride in our experience, expertise, quality and customer service that we provide to meet every consumer's needs. It is our mission to provide excellent customer service from start to completion of a project. To understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a personal and professional manner. Our reputation is based on service, safety and quality, regardless of how large or small the job.

"What ever he plans for the project,He compleat that.He is honest and fair.I will refer him to my friends and family."

Mina R on November 2020

We take great pride in our experience, expertise, quality and customer service that we provide to meet every consumer's needs. It is our mission to provide excellent customer service from start to completion of a project. To understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a personal and professional manner. Our reputation is based on service, safety and quality, regardless of how large or small the job.

"What ever he plans for the project,He compleat that.He is honest and fair.I will refer him to my friends and family."

Mina R on November 2020

Avatar for Springs Construction Corporation

Springs Construction Corporation

881 Hurlingame Ave
New on HomeAdvisorNew on HomeAdvisor
•Approved Pro

Springs Construction Corporation

881 Hurlingame Ave
New on HomeAdvisorNew on HomeAdvisor
•Approved Pro
66 years of experience
Free onsite estimate

Since 1959, Springs Construction has built its reputation on fine craftsmanship, technical expertise and solid project management.We take a proactive, client driven approach to every one of our projects, exceeding our customers vision for their homes. We want you to feel comfortable and safe during the disruption and enjoy your home for years to come.

Since 1959, Springs Construction has built its reputation on fine craftsmanship, technical expertise and solid project management.We take a proactive, client driven approach to every one of our projects, exceeding our customers vision for their homes. We want you to feel comfortable and safe during the disruption and enjoy your home for years to come.

Avatar for Cerletti & Kennedy Design-Build

Cerletti & Kennedy Design-Build

2950 Buskirk Avenue, Suite 300
4.63(
87
)
•Approved Pro

Cerletti & Kennedy Design-Build

2950 Buskirk Avenue, Suite 300
4.63(
87
)
•Approved Pro
Super Service Award
Customers say: True professional
25 local quotes requested
38 years of experience

SPECIALIZING IN HAPPY CUSTOMERS! Cerletti & Kennedy Design-Build is a full service contractor, family owned and operated for three generations. We specialize in room additions, kitchens and all your remodeling needs. We offer comprehensive design services utilizing the latest 3D CAD technology so you can see your design choices before you build. We're prompt and cost effective, our workers are clean and courteous and our customers are satisfied and happy.

"The job got finished overall I was happy with the finish project. The job was not as smooth I had hoped for. I believe my experience on construction and expectation's might have been out of touch. I would for sure let them bid on more work for me if I ever planned to do any more construction."

Larry P on April 2025

SPECIALIZING IN HAPPY CUSTOMERS! Cerletti & Kennedy Design-Build is a full service contractor, family owned and operated for three generations. We specialize in room additions, kitchens and all your remodeling needs. We offer comprehensive design services utilizing the latest 3D CAD technology so you can see your design choices before you build. We're prompt and cost effective, our workers are clean and courteous and our customers are satisfied and happy.

"The job got finished overall I was happy with the finish project. The job was not as smooth I had hoped for. I believe my experience on construction and expectation's might have been out of touch. I would for sure let them bid on more work for me if I ever planned to do any more construction."

Larry P on April 2025

Avatar for Tech Line Construction Inc.

Tech Line Construction Inc.

6114 La Salle Avenue
New on HomeAdvisorNew on HomeAdvisor
•Approved Pro

Tech Line Construction Inc.

6114 La Salle Avenue
New on HomeAdvisorNew on HomeAdvisor
•Approved Pro
93 local quotes requested
5 years of experience

Welcome to Tech Line Construction, your trusted partner in enhancing your home and transforming your wishes into visual and solid realities. With over a decade of unwavering dedication and a commitment to excellence, we have proudly served our clients in delivering top-tier construction solutions. We specialize in providing top-notch services for residential and commercial projects. Our commitment to professionalism, quality, and meticulous attention to detail sets us apart from our competitors. Choose Tech Line Construction for your next construction project and experience the highest level of service and craftsmanship. Bay Area General B Contractor Jose Rodriguez ( General Building contractor ) (510)798-5869 Office@techlineconstruction.info Tech Line Construction inc TechLineconstructiondesign.com CSLB # LIC 1094361 Commercial liability &Worker comp. Insured & bonded

Welcome to Tech Line Construction, your trusted partner in enhancing your home and transforming your wishes into visual and solid realities. With over a decade of unwavering dedication and a commitment to excellence, we have proudly served our clients in delivering top-tier construction solutions. We specialize in providing top-notch services for residential and commercial projects. Our commitment to professionalism, quality, and meticulous attention to detail sets us apart from our competitors. Choose Tech Line Construction for your next construction project and experience the highest level of service and craftsmanship. Bay Area General B Contractor Jose Rodriguez ( General Building contractor ) (510)798-5869 Office@techlineconstruction.info Tech Line Construction inc TechLineconstructiondesign.com CSLB # LIC 1094361 Commercial liability &Worker comp. Insured & bonded

Avatar for Hagenbach Construction

Hagenbach Construction

2668 Cinnabar Hills Ct
4.75(
16
)
•Approved Pro

Hagenbach Construction

2668 Cinnabar Hills Ct
4.75(
16
)
•Approved Pro
Customers say: Quality work
Recommended by 93% of Angi customers
Recommended by 93% of HomeAdvisor customers
16 local quotes requested

Hagenbach Construction is a locally owned and operated company with over 40 years in business with experience in new home construction, room additions, ADU units and Casitas, kitchen and bathroom remodels and all aspects of home remodeling. Let us show you our stress-free, reliable and professional touch for any of your home needs. We're committed to excellence in customer service and professional quality workmanship. Call today to see what expertise can do for the overall value of your project.

"The finished product is nothing short of stunning. They have some incredibly talented craftsmen, and everyone that's been by so far is absolutely speechless! We plan to have them back for future projects. Remodeling is stressful and John & Amy worked diligently to address all concerns in a timely manner. We are very happy with the addition to our home."

Shayna S on August 2023

Hagenbach Construction is a locally owned and operated company with over 40 years in business with experience in new home construction, room additions, ADU units and Casitas, kitchen and bathroom remodels and all aspects of home remodeling. Let us show you our stress-free, reliable and professional touch for any of your home needs. We're committed to excellence in customer service and professional quality workmanship. Call today to see what expertise can do for the overall value of your project.

"The finished product is nothing short of stunning. They have some incredibly talented craftsmen, and everyone that's been by so far is absolutely speechless! We plan to have them back for future projects. Remodeling is stressful and John & Amy worked diligently to address all concerns in a timely manner. We are very happy with the addition to our home."

Shayna S on August 2023

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FAQs for addition to existing structure building service projects in Castro Valley, CA

Yes, hidden rooms are legal, as long as they meet all local building regulations. If you sell your house, most states require homeowners to disclose full houseplans, which would include any hidden rooms.

If your secret room is a safe room, it should contain a means of communication aside from a cell phone, such as a shortwave radio. You should also have plenty of drinking water, a portable generator, emergency food supplies, blankets, pillows, flashlights, batteries and a first aid kit.

Any time you update your home’s square footage, you increase its value, but a secret room is a niche feature that doesn't rank high on every buyer’s list of must-haves. Investing your money in remodeling more common living areas like bedrooms, bathrooms, or kitchens will have a higher ROI than adding a secret room. Many secret rooms can act as entertainment spaces (think a game room or wine cellar) or quiet spaces (a library or study), so when building your secret room you may want to consider its versatility for when you’re ready to sell.

The Castro Valley, CA homeowners’ guide to addition to existing structure building services

From average costs to expert advice, get all the answers you need to get your job done.

See all articles
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