Making High-Performance the Standard

Project superintendent Mike Hume can’t recall a project where they haven’t used stone wool in the building envelope design, whether new construction or retrofit. “I’ve worked with Nick Schiffer for many years, and it’s never been a question of if we’re using stone wool in the envelope, but rather how many assemblies will include it,” he says. “It’s just our standard. Clients come to us knowing this is how we’ll approach the design of their project. It’s not an upgrade they need to ask for or be sold on."

NS Builders is known for building high-performance homes. Nick’s instinct has always been to follow the building science and apply those principles to each project; it’s been his part of his business strategy since the beginning of NS Builders. And that includes material selection for insulation. But you may be surprised to learn he first began including ROCKWOOL stone wool insulation when searching for an acoustic solution in the family home he was building for himself and his wife.

“We knew we were going to have kids, so we wanted to make sure our walls had soundproofing,” Nick says. “We dug into different options and were introduced to ROCKWOOL’s stone wool insulation. We used it for the interior and really enjoyed using it from the install, so we started learning about the potential to use it for other applications as well.” The rest is history.

“People look to Nick for guidance on best practices,” adds Mike. “He knows what he’s talking about from first-hand experience and is committed to sharing his expertise with others in the trade. He wants everyone to apply high-performance principles to their projects, regardless of size. And he focuses on the necessary skill and attention to detail required for the actual construction as much, if not more, than the materials. Everyone in our business benefits from his commitment to education.”

You can learn more about Nick’s commitment to builder education and elevating the trade in this column he wrote for gb&d PRO and tune in weekly for new insights from Nick and a roster of industry leading guests on the Modern Craftsman podcast.

“Insulation isn’t just about meeting code requirements, it’s also not just about ‘filling the cavity’. We’re intentional with the details, the product, and good craftsmanship knowing it will pay dividends for the homeowners when it comes to comfort," says Nick.

This custom home in Needham, Massachusetts is a perfect example of how quality products and craftsmanship contribute to a durable building envelope. The home is 7,900 square feet and in climate zone 5.

The owners of this home clearly had a vision for the stunning aesthetic design that would make it look like it had been there for generations. The distinctive curved roofline and attention to heritage details, like the reclaimed brick, help it meet that objective. But equally important was ensuring they would be building a home that would stand the test of time and be comfortable for its occupants.

ROCKWOOL stone wool insulation products are included in nearly every part of the building envelope, with a few exceptions that were driven by the home’s unusual design features.

More than 4,000 ft² of 3” ROCKWOOL Comfortboard^® 80 was used under the concrete foundation, establishing a durable and high-performing thermal barrier that is required in the northeast. Inside the foundation walls the team also installed 3” of Comfortboard 80 before framing the space; the basement won’t be finished for usable living space until a later time, but this forethought and attention to detail means it will already be warm and dry and ready for cosmetic finishes when the time comes.

The exterior of the home above ground got the same attention to detail. ROCKWOOL Comfortbatt^® R23 was used in the stud cavities to support the air-tight and vapor-permeable assembly—energy efficient, fire-resilient, durable and water resistant to promote drying in the event of leaks without risk of rot or mold.

The interior walls and ceilings were all insulated for fire and sound using ROCKWOOL Safe’n’Sound^®, including the ceiling of the unfinished basement. Nick was unable to spec stone wool for the roof and attic of the home because of its unique, curved design; installation of batts and boards in the non-standard space would be time-intensive, impractical and cost prohibitive.

Early testing of the building envelope shows their efforts are paying off—the home achieved 0.83 exchanges on the blower door test, making it a highly efficient and comfortable space for the homeowners.

“Performance like this isn’t an unreachable goal,” says Nick. "It’s a very attainable objective with the right approach to envelope design and installation, paying as much attention to the craftsmanship details as the products. Our talented crew makes sure the investment in high-performing products is optimized with their skilled installation.”

Watch a portion of the insulation installation on the Needham project in Nick's "Using ROCKWOOL for insulation and sound attenuation" video. He shares best practices for installing stone wool insulation, why interior wall insulation is important, and how his team addressed the structural complexities of the roof with a hybrid approach to insulation.

Foundation:

• Stone
• Comfortboard 80 3”
• 15-Mil Stego
• 6x6 Wire mesh in the slab & #5 rebar @ 12” O.C. in the foundation walls
• 4” Slab & 10” Foundation walls

Basement walls:

Exterior:

• Tremco liquid-applied with Warm-N-Dri 2-3/8” R10 insulation board

Interior:

• Comfortboard 80 3”
• Wood studs in front of the insulation with an open cavity for batt insulation at a later time when finishing the space

Exterior walls (outside in):

• Cedar shingles and Boral ship lap
• Siga Majvest 500SA
• Plywood
• Comfortbatt R23
• Siga Majrex

Interior walls/ceilings/floor:

• 3” Safe’n’Sound in interior walls
• 2x3” Safe’n’Sound in interior ceilings/floors
• No barriers