Customer Testimonials

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The Envelope Group provides an unparalleled combination of product quality, service, knowledge, attention to detail and price. They provide expert insulation installers with fantastic product knowledge as well as an understanding of how their product interacts with all other aspects of construction. We could not recommend them any more highly.

- Cullen Construction, Inc.

I have been building quality homes in the main line for over 15 years. We use the Envelope Group for all of our spray foam and specialty insulation needs. With the ever increasing importance of indoor air quality and energy efficiency, it is good to have a partner like Kirby Slack who totally understands the complexities of R- value, perm ratings and dew points. Our company often refers our clients, building inspectors and other homebuilding professionals to them when codes conflict with up-to-the-minute science, trade publication information or common sense. He is a respected industry expert.

- Andrew M. Kerns

Ranieri & Kerns Associates, LLC. Builders/Construction Managers

I wanted a cleaner solution in my attic than traditional fiberglass insulation. The geothermal consultant who designed a geothermal heating and cooling system for my home suggested I look at spray foam insulation. I liked the insulating quality of spray foam and how it seals so completely. It was also great to have all the old insulation removed and the attic vacuumed out before the spray foam was applied.

I shopped around and found the Envelope Group focused exclusively on spray foam and therefore was more knowledgeable with a better price than the other companies I interviewed.

- Anthony C.

Malvern, PA

We have completed three projects (garage, sunroom and mudroom) using The Envelope Group for spray foam insulation. We have been so pleased with their work we intend to complete another project this fall (basement). Kirby is knowledgeable, professional, responsive and reasonably priced. The work is scheduled promptly and the worksite kept clean. I would highly recommend The Envelope Group for your spray foam insulation needs.

- Emma S.

Wayne, PA

We hired The Envelope Group to replace our 50+ year old insulation with state-of-the-art spray foam insulation. Owner Kirby Slack and his team were courteous and attentive to our particular needs. The project was completed just as promised – in a clean and efficient manner. The home heating and cooling costs will drop significantly because of the new spray foam insulation. We couldn’t be happier with our decision to hire them.

- Scott F.

Radnor, PA

It has been a pleasure working with Kirby! I was initially referred to the Envelope Group by my contractor. We live in an eighty year old house that has no insulation, so when we built our addition this past spring, I needed to be educated about insulation. Not only did my contractor say the only way to go for our project was spray foam insulation, but he also said that the Envelope Group is the only company he works with.

Kirby came out for an estimate and took the time to educate me about the product and process, and was super flexible with our time frame. He is in fact, coming back for stage two of our project in the next month or so. I appreciated their prompt estimate sent by email, and the invoice was sent that way as well. Kirby returned any calls I had within hours & on the day of installation arrived on time, thoroughly explained the process & cleaned up afterward without a trace!

I wouldn’t hesitate to recommend the Envelope Group and look forward to working with Kirby again on future projects.

- Cathy H.

Haverford, PA

I found the Envelope Group online. I left my name and number in the morning and within an hour Kirby Slack returned the call. He came the next morning to measure, and by the afternoon we got the estimate. I called Kirby and said it’s a go with the job. A date was set and he and his technician, Sean came on the designated date. The truck was very well organized and very neat. Kirby and Sean were very courteous, professional and very knowledgeable as we had a few questions. When the job was completed, everything was cleaned up and hauled away. Overall, it was a very pleasant and good experience. There are many people who call themselves professionals, but this company and the people representing it were professionals in every sense of the word. I would recommend them.

- Helen B.

Northeast Philadelphia

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