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Verified record
License not state-verified. We could not confirm a current registration in the state registry. Insurance is self-reported. Look up in the official Massachusetts registry ↗
Highlights
- Decades-long clients — several report 20-plus years of repeat work
- Slate specialist — praised as a rare expert in an uncommon trade
- Honest diagnosis — traced a leak to the chimney instead of the whole roof
Castle Slate Roofing Co. is a Somerville outfit built around one increasingly rare skill: slate roof repair and restoration, plus the custom copper work and gutters that go with it. It's a sole proprietorship — Kevin Williams Sr. has run it for 49 years — serving Somerville, Newton, Boston, Needham, Winchester, Brookline and Wellesley. Its Google page runs 4.9 stars from 17 ratings, and the Better Business Bureau grades it A+. What stands out across the reviews is how long people keep coming back. In a 2023 review, one customer described using Kevin for over 20 years, starting with a major slate-and-metalwork repair when they bought their house and continuing with periodic maintenance since. In a 2022 review, another homeowner said Castle had maintained the original slate roof and copper work on their 1929 Tudor for more than thirty years. A 2024 review describes an 11-year relationship maintaining the slate roof on a 100-year-old Somerville church at what the reviewer called very reasonable prices. One customer put the specialty plainly: Kevin 'seems to be a real expert in this field where there are so few people who are experienced with slate.' In a 2025 review, a homeowner with a leaking roof got a quote from another slate company that was three times higher and had misdiagnosed the source as broad roof damage; Kevin traced it to the chimney, repointed it, and the leak stopped. Jobs described range from single slate replacements to full renovations — one 2026 review describes taking over maintenance of a 1938 church-condo slate roof, including flashing repairs around skylights added during the building's conversion, after a previous contractor had turned the job down as too small. BBB's A+ grade comes with one caveat worth knowing: the business isn't BBB-accredited, and BBB's own page carries no review text or complaint count behind the letter grade. For slate or copper roofing specifically, this is a contractor with an unusually deep, decades-long track record.
What does a roof replacement cost in Greater Boston?
Typical Greater Boston range for this kind of work, from regional averages — not a quote from Castle slate roofing co.. Use it to sanity-check bids, then get the real number in writing.
A square is 100 sq ft of roof surface — bigger than the floor plan because of pitch and overhangs.
Estimated range
$9,000 – $18,600
Typical roofing project around $13,800
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