Twelve reviews in the last six months, and the same step keeps getting named: the prep. SJ CoverUp Wallpaper works out of 242 Main St in Winthrop, run by Sebastian Velez and Johan Pulgarin, who say they set up in Boston in 2025 after more than five years working in Southwest Florida. The trade is deliberately narrow — hanging wallpaper, stripping old paper, and the wall repair and priming that decide whether either goes well.
Customers write about that preparation more than the paper. A May 2026 Google reviewer's living-room job needed wall repair and the whole room painted white before anything went up, and described both owners handling it. Another, in June 2026, wrote about old paper removed, walls prepped, and the process explained up front. In an April 2025 Angi review, a homeowner with a dormered bathroom — varying ceiling heights, a patterned paper that had to line up — said it was finished in under a day and left clean. A February 2026 customer described a nursery mural whose panels landed seamlessly, down to a papered light-switch cover and the crib reassembled.
One account runs the other way, and it is specific. In September 2025 an Angi reviewer gave a single star: the wall was not prepared right, the install was poor with wallpaper overlapping, and when they raised it they found the owner rude and blaming the paper and the wall. That's one job among twenty-three written accounts, nothing since has repeated it, and the six months to August 2026 carry no negatives at all. It is still the thing to ask about, because it failed at exactly the step everyone else praises.
Both owners are named personally in review after review, which tells you who is turning up. The star averages split by platform: Google 5.0 from 9 ratings and Thumbtack 5.0 from 11, against 4.7 from 12 on Angi — where that one-star sits — and HomeAdvisor's matching 4.7 is the same page syndicated, not a second opinion. Both list membership in the Wallcovering Installers Association, and 25 project galleries are posted.
The company says it covers Boston, Worcester, Danvers, Plymouth, Framingham, Lowell, Lawrence and Newburyport, that it is fully insured, and that it has completed over 200 projects across New England and Southwest Florida. For a papered powder room, a mural nursery, or a pattern that has to match around an awkward ceiling, this is a specialist rather than a general painter. Ask how they will prepare your particular walls and get that scope in writing — prep is where the one bad job went wrong.