Verified record
Flagg Builders is a Haverhill, MA outfit co-owned by Keith and Glenn, built around kitchen and bathroom renovations and home additions. Homeowners keep coming back with the same kind of project: a full-gut bathroom or kitchen, a finished basement, or a room built essentially from scratch. The written record is short but unusually consistent: thirteen reviews dated 2019 through 2025 across six platforms, and every one is five stars. On Angi, a homeowner described a full finished-basement build last summer -- a living room, game area, gym and bathroom -- with Keith matching custom trim and materials to a colonial the family had built four years earlier, down to sourcing from the same supplier. Another 2025 review credits Keith with a custom built-in, board-and-batten trim, an accent wall and basement stairwell molding, calling the craftsmanship 'flawless.' A third describes a kitchen-and-bathroom remodel that stayed within its estimate and included a new deck built to match an existing one. A common thread across the reviews is Keith's own hands-on presence -- helping pick tile, walking through options, staying responsive to questions -- rather than a crew working unsupervised. One 2025 review described a project completed under budget on a flexible schedule during the pandemic, spanning two bathrooms, a kitchen, living room, staircase and three bedrooms built essentially from scratch. A single older review, from 2019, praised the same responsiveness and attention to detail on a bathroom remodel, suggesting the pattern isn't new. The company's Massachusetts home improvement contractor registration is verified active with the state. BuildZoom separately lists Keith Flagg's construction supervisor and home improvement contractor licenses as active, with 11 permitted projects on file and a BuildZoom score in the 73rd percentile of Massachusetts contractors. There isn't much to flag before calling -- the written record is thin in volume but carries no complaints, disputes, or negative mentions anywhere in it. What's worth asking about is scope and timeline: several reviews describe large, multi-room projects, so a homeowner with a smaller job should confirm how Flagg Builders scales down and what a typical schedule looks like. For a full kitchen or bathroom remodel, a basement build-out, or an addition where matching existing finish work matters, Flagg Builders' reviews suggest a contractor who does the detail work personally. Worth confirming: current scheduling and how a project of your size compares to the larger remodels the reviews describe.
Flagg Builders LLC is reliable, professional, and meticulous. I used them for my kitchen remodel along with other parts of my house, and I am beyond happy with the results! Highly recommend.
Flagg Builders did a complete finished basement project last summer for us. A living room, game area, gym, and bathroom. Keith is a unicorn in construction. He has the utmost integrity. We had built a custom colonial 4 years ago. Flagg matched all of the custom materials and workmanship. He even went out of his way to use the same custom materials and supplier as our original builder, whom we loved. We also challenged Keith to match the custom first floor stair case in our basement. He relished the challenged and really aced it with very impressive craftsmanship. Leaves the job area immaculate after each, and often long, work days. He is phenomenal to work with not just his talent but his people oriented demeanor. Very personable and friendly. Listens intently. Genuinely cares that his customers are happy. Again this guy is a unicorn. Town inspectors were impressed by his work. One stating ?framing is the best that I?ve seen?. TEN STARS!! Five from me and five from my wife!!
I hired Flagg Builders to renovate a one bedroom rental apartment. Keith was very easy to work with, providing helpful suggestions when needed. All of our questions were addressed quickly. Keith is extremely attentive to detail and completely transformed this apartment into a beautiful living space! We couldn't be happier with our decision to hire Flagg Builders.
Keith and his crew were extremely professional and highly skilled. They came in under budget at the end of the extensive project and they were always prompt and punctual yet flexible with their scheduling (this was during the pandemic). Our project included two full bathrooms, a kitchen, living room, staircase, and three bedrooms from scratch essentially. All the work has held up beautifully and this is a home with four people and two large german shepherds. I highly recommend Flagg Builders to anyone seeking experienced craftsmanship.
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2 changes recorded — last scanned Sep 11, 2026.
Typical Greater Boston range for this kind of work, from regional averages — not a quote from Flagg Builders, LLC. Use it to sanity-check bids, then get the real number in writing.
Estimated range
$23,000 – $35,000
Typical remodeling project around $29,000
Fixed a leak others declined4.7
Fast, single-day roof replacements4.7
Built-in cabinets and dressers4.5
Fast response4.3