T&J Builders specializes in custom ADUs in Dover NH, Portsmouth NH, NH Seacoast, Lakes Region & Southern Maine. Services include garage conversions, in-law suites & detached cottages for rental income, multigenerational living & added property value.

T&J Builders – ADU Contractor in Portsmouth, NH

About T&J Builders

Custom ADU Builders Serving NH Seacoast, Lakes Region & Southern Maine

T&J Builders specializes in designing and building Accessory Dwelling Units (ADUs) for homeowners throughout Dover NH, Portsmouth NH, the New Hampshire Seacoast, the Lakes Region, and Southern Maine. Whether the goal is generating rental income, creating space for family members, or increasing property value, T&J Builders delivers ADUs that are functional and built to last.

An Accessory Dwelling Unit (ADU) is a secondary residential space located on the same property as a primary home. ADUs can take several forms, including:

Detached backyard cottages
Attached additions
Garage conversions
Basement or in-law apartments

These structures offer flexible living solutions while maintaining a degree of privacy and independence for occupants.

Reasons Homeowners Choose to Build an ADU

Homeowners across New Hampshire and Maine are turning to ADUs for a variety of practical reasons:

Rental income to help offset mortgage costs
In-law or multigenerational living arrangements
Guest housing or dedicated home office space
Aging-in-place solutions
Increased overall property value

T&J Builders works with homeowners to determine the most suitable ADU option based on the specific property, available budget, and long-term goals.

ADU Design & Construction Services

As an experienced ADU contractor and custom builder, T&J Builders manages projects from start to finish. Their services include:

Site evaluation and feasibility assessment
Custom ADU design
Permitting and zoning guidance
Foundation, framing, and structural work
Plumbing, electrical, and HVAC installation
Interior finishes and exterior detailing

T&J Builders has working knowledge of local zoning and building requirements in Dover, Portsmouth, and surrounding NH and Maine communities. This familiarity helps support a smoother approval and construction process for homeowners navigating local regulations.

As a detached ADU builder, garage conversion contractor, and in-law suite builder, T&J Builders brings relevant experience to a range of ADU project types. Each project is approached with custom solutions rather than a one-size-fits-all method, with the aim of having the finished ADU complement the existing home.

T&J Builders proudly serves homeowners throughout the following areas:

Dover, NH
Portsmouth, NH
New Hampshire Seacoast
Lakes Region, NH
Southern Maine

For homeowners who are unsure whether their property qualifies for an ADU, T&J Builders can assist in evaluating the options and walking through the process from concept to completion.

Services

T&J Builders performs the following services

Architecture & Design
Permit Specialist
Construction
Feasibility & Site Assessment
Finishing & Fit-out
HVAC installation

T&J Builders Reviews

Alexis McConnell

2026-01-06

"5 Stars. Love them. We have been working with TJ Builders for almost a year now. They started last winter with a large addition into our house. Taylor and his guys were great and quick with problem solving when problems inevitably arose. They were within a week of the proposed timeline for our first project which seems unheard of, especially with the fickle New Hampshire winters. In the spring they added a dormer to the attic and finished it with two bedrooms and a bathroom. They helped rework architectural plans we had previously gotten done that, in reality, did not work. Taylor was accommodating to all the odd requests we had like a bookshelf hidden door to an office, reading nooks in eves, small storage spaces under stairs and a different crazy color in each room. Throughout both projects we added lots of extras as they came up like a generator, radon mitigation and retaining wall with a patio for water mitigation along with a bunch of little things. Taylor and all the guys that work at TJ Builders are super friendly and helpful. Always willing to talk through an issue, help learn a new system or just listen to your mother tell endless stories that seem completely unrelated to anything thats going on. We felt comfortable having them in our space and around our family. I have recommended TJ to anyone who asks and will be going back to them for any future projects."

Karen Kelsey

2025-12-29

"The bottom line is that I am very happy that I chose Taylor and his crew to build my new garage, breezeway and ADU accessory dwelling unit. TJ Builders has completely transformed my little 1954 light blue cape into what looks like a brand new home. It is stunning. Taylor is very responsive and always answers his phone. If you are in the thick of the construction and he knows that he will be unavailable at a certain time, he will tell you in advance so that you know why if he doesnt answer. Any issues that arise, he is very quick to resolve. For instance, I ordered my own kitchen sink, the countertop sub was onsite to measure and informed us that the sink was too large for my space. I contacted Taylor, and within the hour, he found and delivered a new sink for the countertop company to use for their template. The sink and countertops are gorgeous by the way. Taylor has formed a solid team and sub contractor base that produces quality results. To everyone involved with this build: Architect, land surveyor, excavator, foundation contractor, sidingroofing, electrician, plumber, sheetrock flooring, and to Taylor and his finish team Thank you so much. Karen Kelsey"

Joe Bigley

2025-07-31

"Absolutely delighted to share my experience with TJ Builders! Over the past nine years, they have transformed our home in the most incredible ways, and I couldn't be more grateful for their expertise and dedication. From the outset, TJ Builders demonstrated exceptional professionalism and craftsmanship. They built our stunning two-tier back deck, which has become the centerpiece for family gatherings and summer barbecues. The quality of their work is evident in every detail, and the deck has held up beautifully through the seasons. Their team also constructed our outdoor fencing and shower, creating a perfect oasis in our backyard. Its not just functional; it adds a touch of luxury to our outdoor space. The craftsmanship is top-notch, and we have received numerous compliments from friends and neighbors. When it came to renovating our bathrooms, including our master bath, TJ Builders exceeded all expectations. They listened to our ideas and brought them to life with a seamless blend of style and practicality. The quality of the finishes and the attention to detail truly set them apart. Most recently, they completed a stunning remodel of our kitchen, and we are absolutely in love with the results. The layout is more functional, and the design is both modern and inviting. Cooking and entertaining in this space has become a joy, and we owe it all to TJ Builders' vision and craftsmanship. Throughout the years, the team has been incredibly reliable, friendly, and communicative. They have treated our home with the utmost respect and have always gone the extra mile to ensure we are satisfied with the results. Their commitment to quality and customer service is truly commendable. If youre looking for a contractor who will treat your project with care and deliver exceptional results, I wholeheartedly recommend TJ Builders. They have transformed our home into a space we love, and I cant thank them enough for their hard work and dedication!"

Rene Plante

2025-05-09

"We used TJ Builders recently to update a small upstairs bath. Taylor and his team did a wonderful job for us. Taylor was very easy to work with. He listened to our ideas and gave us exactly what we asked for. Taylor's subs were very professional and respectful of our home. Consider TJ Builders for your nexy project, you won't be disappointed."

Mike Layton

2025-02-18

"We've been planning a big project for quite a while so when it was time to find a builder, we were focused on doing our due diligence and doing it right. While we interviewed four different builders, our first call was to TJ Builders and Taylor picked up our first call even though it was a Saturday. Since that first phone call, Taylor has provided A communication and customer service. Additionally, Taylor was the only builder to show up with an architect which was extremely important given where we were in the planning process. Knowing the builder and architect have a good working relationship would seem to improve the process and it certainly did. With any plan, we made some adjustments along the way and Taylor rolled with them, always focused on making sure we got the addition we were dreaming of. All of this combined with the great group of guys that make up Taylor's crew, ensured a smooth process and an addition that turned out exactly as we hoped. We can't recommend Taylor and TJ Builders enough!!"

prev next

Specifics

Opening hours

Monday open 24h

Tuesday open 24h

Wednesday open 24h

Thursday open 24h

Friday open 24h

Saturday open 24h

Sunday open 24h

Location

Get directions

Did we help?

Please let T&J Builders know that you found them on Top ADU Pros to allow us to continue helping others find the best adu contractors.

get in contact

T&J Builders