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Find Addition to existing structure builders in Greenwich

Avatar for MDI Construction, LLC

MDI Construction, LLC

81 Kensett Dr
4.64(
18
)
Approved Pro

MDI Construction, LLC

81 Kensett Dr
4.64(
18
)
Approved Pro
Customers say: Quality work
Recommended by 94% of Angi customers
Recommended by 94% of HomeAdvisor customers
13 years of experience

We are a locally owned and operated company with over 10 years of industry experience. We value honesty and integrity in all aspects of our business. We offer a variety of home improvement services that are customizable to each individual project. We specialize in carpentry work and a variety of related service and repair 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 with our clients and guarantee your satisfaction!

"Very professional, courteous, timely, knowledgeable and amazing workmanship! Very pleased with their service, plan to use them going forward for all my home upgrades."

Pam M on April 2023

We are a locally owned and operated company with over 10 years of industry experience. We value honesty and integrity in all aspects of our business. We offer a variety of home improvement services that are customizable to each individual project. We specialize in carpentry work and a variety of related service and repair 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 with our clients and guarantee your satisfaction!

"Very professional, courteous, timely, knowledgeable and amazing workmanship! Very pleased with their service, plan to use them going forward for all my home upgrades."

Pam M on April 2023


All Phase Construction II, LLC

12 Little Quarry Lane
4.67(
3
)
Approved Pro

All Phase Construction II, LLC

12 Little Quarry Lane
4.67(
3
)
Approved Pro
Customers say: Quick response
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
17 years of experience

All Phase Construction II, LLC, specializes in all aspects of home improvement from large remodeling projects all the way down to finish work. There is not a project we can't handle. Give us a call today for an estimate on your next project!

"Excellent job. Great craftsmanship. Mannerly. Cleaned up after themselves. Had addition put on the house (master bath). Honest. Respectful and talented craftsmanship. Meticulous workers. Highly recommend this company. Would do it again in the future. The owner is a businessman with honesty and intelligence. Thank you for such a great looking bath and renovation to our basement. Love it."

Charles B on July 2020

All Phase Construction II, LLC, specializes in all aspects of home improvement from large remodeling projects all the way down to finish work. There is not a project we can't handle. Give us a call today for an estimate on your next project!

"Excellent job. Great craftsmanship. Mannerly. Cleaned up after themselves. Had addition put on the house (master bath). Honest. Respectful and talented craftsmanship. Meticulous workers. Highly recommend this company. Would do it again in the future. The owner is a businessman with honesty and intelligence. Thank you for such a great looking bath and renovation to our basement. Love it."

Charles B on July 2020


Avatar for JR General Contractor, LLC

JR General Contractor, LLC

22 Olive Street
4.83(
15
)
Approved Pro

JR General Contractor, LLC

22 Olive Street
4.83(
15
)
Approved Pro
Customers say: Quick response
15 years of experience
Free onsite estimate

JR General Contractor LLC, is committed to excellence 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.

"Yes they did an excellent job"

Louise R on May 2025

JR General Contractor LLC, is committed to excellence 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.

"Yes they did an excellent job"

Louise R on May 2025


Avatar for AI Art and Design

AI Art and Design

3 AVONDALE RD
5.00(
7
)
Approved Pro

AI Art and Design

3 AVONDALE RD
5.00(
7
)
Approved Pro
3 years of experience
Free onsite estimate

We are a design studio with over 10 years of international experience. We'll help you hone your style, get inspired, and realize your design dreams. Beyond design we are also project managers and custom builders. This means we can deliver a project to our clients from start to finish, by streamlining the process and understanding the feasibility of each design.

"We hired Ion and AI Art and design after lengthy process with many others. He showed a high understanding of design and a sensitive. He designed and took us through the whole process with other professionals in the design and construction phases. It was a pleasure seeing everything coming together. The house looks spectacular. We highly recommend working with AI and Ion on your project. "

Michael B on July 2025

We are a design studio with over 10 years of international experience. We'll help you hone your style, get inspired, and realize your design dreams. Beyond design we are also project managers and custom builders. This means we can deliver a project to our clients from start to finish, by streamlining the process and understanding the feasibility of each design.

"We hired Ion and AI Art and design after lengthy process with many others. He showed a high understanding of design and a sensitive. He designed and took us through the whole process with other professionals in the design and construction phases. It was a pleasure seeing everything coming together. The house looks spectacular. We highly recommend working with AI and Ion on your project. "

Michael B on July 2025


Avatar for Newfield Development Company

Newfield Development Company

201 Marshall Ridge Road
5.00(
1
)
Approved Pro

Newfield Development Company

201 Marshall Ridge Road
5.00(
1
)
Approved Pro
Customers say: Quick response
Recommended by 100% of Angi customers
Recommended by 100% of HomeAdvisor customers
33 years of experience

We provide a full range of contracting and construction management services. Planning, pre-construction and construction services can be delivered in a variety of ways to meet the specific needs of your project. Our projects include - New Homes - Additions, large & small - Renovations - New Kitchens - New Baths - Elevator Installations - Land Development - Sub-divisions - Home Repairs - Basement De-watering

"He was honest, completely upfront and trustworthy. He kept us informed of what was happening, and overall did a great job--very happy!"

Catherine N on August 2014

We provide a full range of contracting and construction management services. Planning, pre-construction and construction services can be delivered in a variety of ways to meet the specific needs of your project. Our projects include - New Homes - Additions, large & small - Renovations - New Kitchens - New Baths - Elevator Installations - Land Development - Sub-divisions - Home Repairs - Basement De-watering

"He was honest, completely upfront and trustworthy. He kept us informed of what was happening, and overall did a great job--very happy!"

Catherine N on August 2014


Avatar for J A L Construction

J A L Construction

334 Exeter St
5.00(
6
)
Approved Pro

J A L Construction

334 Exeter St
5.00(
6
)
Approved Pro
Customers say: Quick response
50 years of experience
Free onsite estimate

J A L Construction has over 50 years of experience delivering high-quality construction and remodeling services. Our experience speaks for itself—we take pride in reliability, clear communication, and craftsmanship that stands the test of time. Whether you’re planning a full home addition, remodeling your kitchen or bathroom, or updating your exterior, we bring skill and dedication to every job. Our services include additions, major renovations, kitchen and bath remodels, deck and porch builds, siding installation, structural steel beam work, window replacement, and brick, stone, or paver patios and walkways. We work closely with homeowners to understand their vision and deliver results that exceed expectations. At J A L Construction, no job is too big or small. We look forward to earning your trust and helping bring your next project to life.

"The job was done in a timely manor without any issues. This was important because it is my rental unit,"

Sharon Z on August 2025

J A L Construction has over 50 years of experience delivering high-quality construction and remodeling services. Our experience speaks for itself—we take pride in reliability, clear communication, and craftsmanship that stands the test of time. Whether you’re planning a full home addition, remodeling your kitchen or bathroom, or updating your exterior, we bring skill and dedication to every job. Our services include additions, major renovations, kitchen and bath remodels, deck and porch builds, siding installation, structural steel beam work, window replacement, and brick, stone, or paver patios and walkways. We work closely with homeowners to understand their vision and deliver results that exceed expectations. At J A L Construction, no job is too big or small. We look forward to earning your trust and helping bring your next project to life.

"The job was done in a timely manor without any issues. This was important because it is my rental unit,"

Sharon Z on August 2025


"I recently had an asphalt driveway put in. The crew was very professional. The driveway is smooth and very happy with the quality of the new driveway. They even went above and beyond and put in a small drainage area for water runoff. It has definitely improved the appearance of my home."

Elaine A on February 2025

Omega Development is a Fairfield, County staple. With over 20+ years of experience Omega is your one stop shop for all things construction.

"I recently had an asphalt driveway put in. The crew was very professional. The driveway is smooth and very happy with the quality of the new driveway. They even went above and beyond and put in a small drainage area for water runoff. It has definitely improved the appearance of my home."

Elaine A on February 2025


"Inson is a creative genius with a superb eye. He did everything with meticulous detail and completely transformed our apartment into an amazing, gorgeous home. We enjoy entertaining, and our friends love coming over, always remarking how beautiful and inviting our home is- and that was exactly what we wanted, except Inson brilliantly upgraded our concept, within budget and on time (even with our aggressive timeline because we needed to be out of our old place and into our new within months!). Inson’s team was also great to work with - always polite and professional. We highly recommend Inson and plan on working with him again on our Hamptons home!"

Sandy T on November 2021

Full Service Residential Design Firm that focuses on full transparency and meeting our clients budget and timeline. Impeccable attention to detail and cost analysis are our strong point. A full design team takes your project from inception to completion in record time.

"Inson is a creative genius with a superb eye. He did everything with meticulous detail and completely transformed our apartment into an amazing, gorgeous home. We enjoy entertaining, and our friends love coming over, always remarking how beautiful and inviting our home is- and that was exactly what we wanted, except Inson brilliantly upgraded our concept, within budget and on time (even with our aggressive timeline because we needed to be out of our old place and into our new within months!). Inson’s team was also great to work with - always polite and professional. We highly recommend Inson and plan on working with him again on our Hamptons home!"

Sandy T on November 2021


Avatar for Douglas Marshall Cooper Associates, LLC

Douglas Marshall Cooper Associates, LLC

57 Westchester Avenue
4.63(
22
)
Approved Pro

Douglas Marshall Cooper Associates, LLC

57 Westchester Avenue
4.63(
22
)
Approved Pro
Customers say: Quick response
29 years of experience
Free onsite estimate

Douglas Marshall Cooper Associates is a full-service design and construction firm whose practice encompasses both new and existing buildings of residential and commercial use, as well as speculative housing and development. Mr. Cooper’s office is located in Pound Ridge, New York and includes a staff of himself, an associate partner, three assistants and a host of carpenters, masons, and laborers, in addition to various subcontractors that work on projects small to large. Douglas Marshall Cooper Associate's roots are based in Construction, Design, Real Estate Investment and Development & Construction Management. Our portfolio includes a wide range of work across these fields. Our uniqueness comes from understanding what it is to be the Owner, the Developer and the Builder –- a trifecta that is evident in DMC Associate's core portfolio of prestigious residential, commercial, and corporate projects. Douglas Marshall Cooper Associates, LLC...a solid track record. A powerful future.

"I wish I could give zero stars. We hired Douglas for a kitchen remodel which involved installing a kitchen island, pantry, and all the related plumbing and electrical work. The communication between Douglas and his carpenter was terrible. We submitted sketches and agreed upon the design for the cabinets which were meant to be overlaid. When the island arrived, the cabinets were inset which did not match the rest of the kitchen. In addition, the kitchen island has split and cracked at more than half of the joints. The pantry cabinet has split and areas of unpainted MDF are showing. We have needed to paint and touch up many of these spots. Regarding the plumbing, we have had multiple significant leaks from piping and tubing that the team installed. Water has leaked even through the floor and into the basement. Upon review from other plumbers, all have confirmed the parts used were cheap and of low quality, and the workmanship was subpar. After a major leak in the middle of the night, we reached out to Douglas and respectfully voiced our issues and complaints. He ignored us for a full month, and then instead of simply stopping by to take a look at the problems (which would have been the first major step to alleviating our frustrations), he responded in a despicable manner. He even included the following quote from his lawyer, He laughed saying that perhaps you lost your job (due to the CoronaVirus) and were probably scrounging for any money you could scrape up. Who would want to work with someone like this?"

Keri P on October 2020

Douglas Marshall Cooper Associates is a full-service design and construction firm whose practice encompasses both new and existing buildings of residential and commercial use, as well as speculative housing and development. Mr. Cooper’s office is located in Pound Ridge, New York and includes a staff of himself, an associate partner, three assistants and a host of carpenters, masons, and laborers, in addition to various subcontractors that work on projects small to large. Douglas Marshall Cooper Associate's roots are based in Construction, Design, Real Estate Investment and Development & Construction Management. Our portfolio includes a wide range of work across these fields. Our uniqueness comes from understanding what it is to be the Owner, the Developer and the Builder –- a trifecta that is evident in DMC Associate's core portfolio of prestigious residential, commercial, and corporate projects. Douglas Marshall Cooper Associates, LLC...a solid track record. A powerful future.

"I wish I could give zero stars. We hired Douglas for a kitchen remodel which involved installing a kitchen island, pantry, and all the related plumbing and electrical work. The communication between Douglas and his carpenter was terrible. We submitted sketches and agreed upon the design for the cabinets which were meant to be overlaid. When the island arrived, the cabinets were inset which did not match the rest of the kitchen. In addition, the kitchen island has split and cracked at more than half of the joints. The pantry cabinet has split and areas of unpainted MDF are showing. We have needed to paint and touch up many of these spots. Regarding the plumbing, we have had multiple significant leaks from piping and tubing that the team installed. Water has leaked even through the floor and into the basement. Upon review from other plumbers, all have confirmed the parts used were cheap and of low quality, and the workmanship was subpar. After a major leak in the middle of the night, we reached out to Douglas and respectfully voiced our issues and complaints. He ignored us for a full month, and then instead of simply stopping by to take a look at the problems (which would have been the first major step to alleviating our frustrations), he responded in a despicable manner. He even included the following quote from his lawyer, He laughed saying that perhaps you lost your job (due to the CoronaVirus) and were probably scrounging for any money you could scrape up. Who would want to work with someone like this?"

Keri P on October 2020


Avatar for Above & Beyond Contracting

Above & Beyond Contracting

47 Ethelridge Rd
4.96(
72
)
Approved Pro

Above & Beyond Contracting

47 Ethelridge Rd
4.96(
72
)
Approved Pro
Customers say: Quick response
Recommended by 98% of Angi customers
Recommended by 98% of HomeAdvisor customers
23 local quotes requested

Above & Beyond Contracting excels in all areas of residential home improvement and commercial needs. Our work includes state of the art kitchens, baths, basements, windows/doors, decks and more. Our commitment to the customer is our number one priority. Our staff is professional, dependable, and honest. Let us make your design ideas a reality. 914-681-6080.

"If you're looking to remodel, hire Bud at Above & Beyond Contracting! Him and his crew were reliable, trustworthy, friendly and easy to work with. His quote was by far the most detailed & fair I received. If there was an issue, he put your mind at ease and took care of it. He recommended details I didn't even think of and it elevated the remodel & I love it. I am so happy with my renovation and couldn't be happier that I went with Above & Beyond Contracting."

Chris R on June 2025

Above & Beyond Contracting excels in all areas of residential home improvement and commercial needs. Our work includes state of the art kitchens, baths, basements, windows/doors, decks and more. Our commitment to the customer is our number one priority. Our staff is professional, dependable, and honest. Let us make your design ideas a reality. 914-681-6080.

"If you're looking to remodel, hire Bud at Above & Beyond Contracting! Him and his crew were reliable, trustworthy, friendly and easy to work with. His quote was by far the most detailed & fair I received. If there was an issue, he put your mind at ease and took care of it. He recommended details I didn't even think of and it elevated the remodel & I love it. I am so happy with my renovation and couldn't be happier that I went with Above & Beyond Contracting."

Chris R on June 2025

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FAQs for addition to existing structure building service projects in Greenwich, CT

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 Greenwich, CT 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.