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603 Contracting LLC

Carpentry Framing - Install, Construction Manager, Deck or Porch - Build or Replace- For Business,

About us

603 Contracting is a trusted general contractor based in Derry, NH, serving homeowners and businesses throughout southern New Hampshire. We specialize in residential remodeling, additions, new home construction, and commercial tenant improvements, delivering high-quality craftsmanship with a professional and reliable approach. Our team is committed to clear communication, structured project management, and maintaining a clean, organized work environment. From kitchen and bathroom renovations to full home builds and commercial fit-ups, we handle projects of all sizes with attention to detail and a focus on customer satisfaction. Contact us today to discuss your construction needs!

Business highlights

Se habla espanol
7 years of experience

Amenities

Free Estimates

Yes

Accepted Payment Methods

  • CreditCard
Reviews
5.017 Reviews
Number of StarsImage of DistributionNumber of Ratings
5
100%
4
0%
3
0%
2
0%
1
0%

Filter reviews by service

Showing 1-17 of 17 reviews
Kyle W.
Jan 2026
5.0
Mike was very professional, communicated clearly, and finished the job in a timely manner. Great experience overall.

Joe M.
Jan 2026
5.0
We hired 603 Construction during Covid to build an addition on our home, and the result completely transformed how we live in the space, especially our kitchen, which has become the heart of our home and an incredible gathering place for family and friends. Like any major project (especially during Covid), there were challenges along the way, but Mike and team handled them and delivered a final product that has created lasting memories for my family and friends. Great group of guys that work hard to deliver! Highly recommend!!

Homeowner
Jan 2026
5.0
$22,500
I hired 603 contracting to finish my basement, they did a great job.

Kyle B.
Jan 2026
5.0
Addition to Existing Structure - Build - For Business
Top quality service at exceptional pricing, can’t say better things about Mike and his team at 603, they were great to work with!

Leonard B.
Jan 2026
5.0
$14,000
They did a great job renovating my kitchen. I will hire them again for my next project.

Brian S.
Jan 2026
5.0
$15,000
On time on budget and a pleasure to have in the house.

Victor M.
Jan 2026
5.0
Had a basement flood. After the clean up/drying 603 came in and rebuilt my basement beautifully. Put down new wood floors/sleeper system, hung drywall, and painted. Came out better than it was before the flood. Very professional and great work!

Frank L.
Jan 2026
5.0
Mike and his crew were great with out kitchen remodel. They were on time every day, managed the project efficiently and gave us a great price. Highly recommend.

Tom G.
Jan 2026
5.0
Addition to Existing Structure - Build - For Business
We hired 603 Contractingfor an addition project and couldn’t be happier with the result. From the initial planning through completion, the work was well-organized, professional, and done to a high standard. Communication was clear throughout the project, timelines were realistic, and any questions or changes were handled promptly and fairly. The craftsmanship and attention to detail really showed, and the job site was kept clean and safe during construction. The project was completed as expected, and the final result exceeded our expectations. I would absolutely recommend this contractor to anyone considering an addition or major home improvement project and would not hesitate to work with them again.

Emmanuel G.
Jan 2026
5.0
Laminate Wood or Stone Flooring - Install - For Business
$15,000
Professional, reliable, and high-quality work. Everything was completed on schedule and exceeded expectations. Highly recommended!

Patrick E.
Jan 2026
5.0
$15,000
The best company around! Amazing work done by even better people! Highly recommend to everyone!

Matt B.
Jan 2026
5.0
work was dpnd well and on time with gpod communication

Calvin C.
Jan 2026
5.0
Excellent job these guys are my go to for any home improvement projects. They remodeled my basement and redid my kitchen / bathroom floors etc. Communication was easy any questions I had. They answered almost immediately 10 out of 10. Will be using them again!

Amanda M.
Jan 2026
5.0
$50,000
Detailed craftsmanship and honest pricing!

Patricia B.
Jan 2026
5.0
603 contacting , was awesome . Built me a full bathroom in my lower level that is amazing . Also built a ramp in my garage for my ill husband . Micheal and all his guys were great !!

Patrick E.
Jan 2026
5.0
Google Review
My Father in Law had a heart attack and we needed someone to help with snow removal asap. I called Mike from 603 and within 2 hours He was at my father in laws house! What an amazing company and such a great person! Even with a packed schedule, he made this a priority! I would recommend 603 Contracting to everyone that needs anything construction related or snow removal! Thank you!

Raymond N.
Jan 2026
5.0
Google Review
I found Mike online, he and his completed my stairs in 1 day and they look great. He explained everything and his team where clean and respectful.

Licensing

State Contractor License Requirements

All statements concerning insurance, licenses, and bonds are informational only, and are self-reported. Since insurance, licenses and bonds can expire and can be cancelled, homeowners should always check such information for themselves. To find more licensing information for your state, visit our Find Licensing Requirements page.

*Contact business to see additional licenses.

FAQ

603 Contracting LLC is currently rated 5.0 overall out of 5.

603 Contracting LLC accepts the following forms of payment: CreditCard

Yes, 603 Contracting LLC offers free project estimates.

No, 603 Contracting LLC does not offer eco-friendly accreditations.

No, 603 Contracting LLC does not offer emergency services.

No, 603 Contracting LLC does not offer warranties.