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Top-Rated Addition to existing structure builders in Cos Cob - Updated Nov 2026

Avatar for A2Z Contractors, LLC
A2Z Contractors, LLC
4.6(
133
)
Addition to Existing Structure - Build

Serving Cos Cob, CT and surrounding areas

Approved

In business since 2010

Free estimates

Emergency services offered

"I recently hired A-Z Contracting and Weslyn for a laundry room build and a bathroom renovation, and I couldn’t be happier with the results. They built our new laundry room from scratch, including all new plumbing, electrical work, and a new dryer vent installation. They also renovated and extended our bathroom, and the finished space looks fantastic. Weslyn and his team were trustworthy, punctual, and extremely reliable throughout the entire project. I felt completely comfortable giving them access to my home while I wasn’t there, which says a lot about their professionalism and integrity. The craftsmanship is excellent, and the attention to detail really shows in the finished work. All of the workers were knowledgeable, polite, and respectful of our home. The project was completed efficiently and to a very high standard. I would absolutely use A-Z Contracting again and highly recommend Weslyn and his team to anyone looking for quality work done right."
bathroom
bathroom
bathroom
bathroom
bathroom

+5

Response time2 days
16 neighbors recently requested a quote
Recommended by89%of homeowners
Avatar for Tapia Home Improvement
Tapia Home Improvement
4.9(
27
)
Addition to Existing Structure - Build

Serving Cos Cob, CT and surrounding areas

Approved

In business since 2008

Free estimates

Warranties offered

"I recently had the pleasure of working with Miguel and his team on a major renovation of my house, which took about five months to complete. Throughout the entire process, Miguel was incredibly patient and attentive, ensuring that everything was done to the highest standards. His workers were always punctual, professional, and dedicated to their work. The quality of the renovation is outstanding, and I couldn't be happier with the results. Even now, if I run into any small issues, Miguel is always willing to come by and check it out, promptly fixing any problems. I highly recommend Miguel and his team for any renovation projects."
Additional Photos
Additional Photos
Additional Photos
Additional Photos
Additional Photos

+75

Response time5 days
Response rate100%
2 neighbors recently requested a quote
Avatar for RockSolid Construction, LLC
RockSolid Construction, LLC
4.6(
26
)
Addition to Existing Structure - Build

Serving Cos Cob, CT and surrounding areas

Approved

In business since 1992

Free estimates

Small jobs welcome

"I hired Jeff and his quote was extremely competitive. More importantly his references were impeccable. Overall the work came out great. However there were several little things that I had to catch and a few very minor things that did not get done. Overall we are very happy with how it worked out."
Response time5 hrs
Response rate100%
2 neighbors recently requested a quote
Avatar for MDI Construction, LLC
MDI Construction, LLC
4.4(
19
)
Addition to Existing Structure - Build

Serving Cos Cob, CT and surrounding areas

Approved

In business since 2012

Free estimates

Offers commercial services

"This man Misha performed a miracle for me! My custom railings came out exactly they way they were supposed to. The price was great and I will definitely hire him again to do more work! Thank you Misha!"
Full House Renovation
Interior works. Greenwich
New Home Building
Full House Renovation
Interior works. Greenwich

+49

Response time6 hrs
Response rate100%
Recommended by94%of homeowners
Avatar for JR General Contractor, LLC
JR General Contractor, LLC
4.8(
15
)
Addition to Existing Structure - Build

Serving Cos Cob, CT and surrounding areas

Approved

In business since 2010

Free estimates

Small jobs welcome

"Prices are very reasonable and performs an excellent quality of work. He takes time to answer your questions and is very professional in dealing with his customers. Highly recommended, and will definitely hire for future projects."
Footings starts
Footings starts
footings
concrete day
concrete day

+65

Response time2 days
Recommended by86%of homeowners
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FAQs for addition to existing structure building service projects in Cos Cob, CT

You can typically raise your roof by four to eight feet, depending on your home's structure and roof design. The exact amount depends on factors like roof slope and framing support. Raising the roof creates additional interior space, enhances natural light, and increases your home's value. Consult a professional to determine the feasible height increase for your home.

Yes, you need a building permit to raise your roof. Obtaining a building permit ensures your project complies with local building codes and safety regulations. A professional contractor can assist with the permit and inspection process and ensure all legal and safety requirements are met. Your contractor will be familiar with building codes in your area, which can differ between cities or states.

While it's possible to raise a flat roof, it requires extensive structural modifications. Flat roofs lack the attic space and support structures of pitched roofs, so raising them involves significant engineering to ensure safety and durability. This process can be complex and costly, so professional assessment is essential before undertaking a project of this magnitude.

The Cos Cob, 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.