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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


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.


JJ Builders Inc

14686 Hanover St
New on HomeAdvisorNew on HomeAdvisor
Approved Pro

JJ Builders Inc

14686 Hanover St
New on HomeAdvisorNew on HomeAdvisor
Approved Pro
3 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!

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!


Avatar for SAN & ZOE GENERAL CONTRACTOR INC

SAN & ZOE GENERAL CONTRACTOR INC

1317 PALMERA AVE
New on HomeAdvisorNew on HomeAdvisor
Approved Pro

SAN & ZOE GENERAL CONTRACTOR INC

1317 PALMERA AVE
New on HomeAdvisorNew on HomeAdvisor
Approved Pro
24 local quotes requested
10 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!

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!


Golden View Renovation, Inc.

1630 Oakland Rd Ste A217
New on HomeAdvisorNew on HomeAdvisor
Approved Pro

Golden View Renovation, Inc.

1630 Oakland Rd Ste A217
New on HomeAdvisorNew on HomeAdvisor
Approved Pro
5 years of experience

Golden View Renovation Inc. is committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our clients. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our clients' interests and make their concerns the basis of our business.

Golden View Renovation Inc. is committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our clients. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our clients' interests and make their concerns the basis of our business.


Avatar for Benlo Remodeling

Benlo Remodeling

41041 Trimboli Way, Unit 1141
5.00(
4
)
Approved Pro

Benlo Remodeling

41041 Trimboli Way, Unit 1141
5.00(
4
)
Approved Pro
Free onsite estimate

benloremodeling.com We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests, and make their concerns the basis of our business.

"I hired Ben and Lorena to convert my basement into livable space . They added bathroom and bedroom , they repaired a retaining wall took care of all the structural modifications. It was such a smooth process with them and they were very informative . I recommend them with my family members and friends . "

Joshua R on August 2025

benloremodeling.com We are committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests, and make their concerns the basis of our business.

"I hired Ben and Lorena to convert my basement into livable space . They added bathroom and bedroom , they repaired a retaining wall took care of all the structural modifications. It was such a smooth process with them and they were very informative . I recommend them with my family members and friends . "

Joshua R on August 2025

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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.

  • A renovated kitchen with a waterfall island

    HomeAdvisor’s DIY Kitchen Remodel Cost Guide looks at the cost of buying supplies and doing the work yourself. Find the key cost factors and how to cut expenses.

  • Secret room within bookcase

    HomeAdvisor's expert guide walks you through the cost to build a secret room, whether you're creating a safe room for security or a fun space to fulfil your childhood fantasies. Use this guide to help plan your secret room project and explore room, concea

  • outdoor patio bar

    Explore the cost to build a bar in your home and learn how materials, wet vs. dry bars, and labor costs influence the total price of your project.