Green Stamp Insulation
Local business · 184 Riverview Ave, Waltham, MA 02453, USA
Their work
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Verified record
Highlights
- Difficult attics — took a 2023 job other companies refused to quote
- Site protection — 2023 crew masked HVAC in plastic before spraying
- First-pass inspection — a 2022 4,500 sq ft home passed on the first try
- Free follow-up — returned a year later to touch up at no charge
- In-house expertise — a HERS rater who taught an energy-code class
- Mass Save work — several customers found them through the program
- Surface damage — a 2014 customer reported a cracked ceiling and wall
- Repair handling — that same customer said repairs went poorly
- Dated accounts — most written reviews date from 2022 and 2023
- Registration — the active licence status comes from a directory, unverified
Several insulation companies would not even quote the job. That is what a homeowner wrote in November 2023 about their complicated attic — and Green Stamp took it on, quoted it accurately, gave a fast install date, and turned up on time every day until it was finished. The Waltham company has been an insulation contractor at the same Riverview Avenue address for years; a North Shore magazine listed it there in October 2017, and its Better Business Bureau profile records 23 years in business from a 2003 incorporation, with 19 employees and an A+ grade. That profile also carries the alternate name Moldtec America and describes mold remediation and removal, so the same outfit works both sides of the building envelope. What customers describe is spray foam and attic work, and the detail they go into suggests they knew what they were watching. A January 2023 customer said the crew arrived at 7:30 and spent the first couple of hours masking off the HVAC with plastic before any foam was sprayed, then worked to about four o'clock without stopping for lunch. In October 2022 another said a 4,500-square-foot house was insulated in ten days and passed inspection on the first try, with everything covered and the site cleaned afterwards. A 2022 reviewer planning an age-in-place renovation called the conserving envelope the hardest part of the whole project. One of the company's people, Ben Marshal, spoke on spray foam and building energy code at a construction supervisor renewal class in 2022 and is a HERS rater. Several of these homeowners found the company through Mass Save. The one bad account is old and specific. In an August 2014 review a Mass Save customer said blown-in insulation opened a nine-foot crack in their dining room, spread insulation and debris through the house and cracked a bedroom wall, and that the repairs were not handled helpfully. Twelve years is a long time, but a damage-and-repairs complaint deserves naming. Most of the written accounts date from 2022 and 2023, with the newest from August 2025 — a former owner of S+H Construction who said the company came back almost a year after the job to touch up areas at no charge. Two things to settle before you sign: BuildZoom shows a Massachusetts home improvement contractor registration as active, checked in March 2026 by the directory rather than by us, so confirm the number with the state yourself; and ask how finished surfaces get protected and repaired on a blow-in job, since that is precisely what went wrong in the 2014 account.
Heard around town
News & the web
- MixedSustainable Design in Manchester-by-the-SeaOct 10, 2017
“Insulation Contractor Green Stamp Co. 184 Riverview Ave. Waltham, MA 02453”
— Northshore Magazine, nshoremag.comRead the article ↗
Read the comments
Most recent comments
- 5.0Aug 29, 2025
As the former owner of S+H Construction, I have known Greenstamp for years. Last year we renovated our own home and Greenstamp did an outstanding job. They even came back almost a year later to touch up some areas at no charge. Great company !
— Doug HannaView on Google Reviews ↗ - 5.0Nov 28, 2023
Very professional, knowledgeable and pleasant to work with. Company came out, gave accurate quote, provided fast installation date, and was on time each day until the job was completed. Our house has a complicated attic, which several companies refused to even quote.. there were a couple of issues that occurred during install, but they very quickly resolved them! I would work with green stamp for any future insulation projects on our house. A+++
— Dmitry EpsteinView on Google Reviews ↗ - 5.0Jan 10, 2023
The men at Green Stamp arrived at 7:30 and worked straight until the job was done at around 4:00, not even stopping for lunch. They spent the first couple of hours just preparing the job, putting up plastic to protect the HVAC, etc., before they started spraying. They were very courteous and did a very good, clean job. I was quite nervous about having spray foam insulation in my home, having heard that if it's not installed correctly, I might have off- gassing. But Green Stamp was slow and careful, and the spray foam cured in a couple of hours, and there are no fumes whatsoever. Thank you Green Stamp! (Caitlin from Concord, Mass)
— Caitlin SelleView on Google Reviews ↗ - 5.0Nov 11, 2022
When we decided to age in place, it became clear that our home would require renovation and a small addition. Our goal was to create a structure with a conserving envelope, energy production, and high efficiency mechanics. The most challenging, by far, was the conserving envelope. In 2019, it was suggested that I contact Ben Marshall of GreenStamp. I called him, and most impressively, he came to the house, looked at the plans and explained insulation and the options to me. The project, which was to start in April 2020, did not begin till the fall of 2021. When it was time to insulate in the fall of 2022, Ben again came to the house to look at the areas to be insulated. For many reasons, this was a complicated project. The crew arrived with detailed instructions. The lead on the crew has worked at GreenStamp for fifteen years. A company does not get this kind of loyalty unless they are doing something right. His longevity with the company and with the installation of insulation was very reassuring. And he was well informed about the project. Over the months and years, Ben and Andrew had the patience of saints. They answered question after question, responded to email after email, understood my desire for a net zero envelope, and although they may have wanted to leave this project, they never did. They were timely and thorough in response. I think the most important aspects are their encyclopedic knowledge about insulation, their respect for their customers, their training and education of their employees, and the care they took with the installation. We could trust them implicitly. The insulating envelope of this building reaches net zero standards for this climate, is everything, I’d hoped for, and I can’t recommend GreenStamp highly enough. Jocelyn Tager
— Jocelyn TagerView on Google Reviews ↗ - 5.0Oct 29, 2022
They just completed 4500sq ft home in ten days. Great job insulating - everything passed inspection on the first try. Also, they took care to cover every single item in the house and then did a good job cleaning. Awesome job!
— Randall PerezView on Google Reviews ↗
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Update history
Added 11 new comments, added 16 new photos, established rating 3.9
- behind the score: 2014 damage complaint — cracked ceiling and wall during a Mass Save blow-in job