Case Study: Shaft Wall Alternative

Codewatcher FlameBlock at Tapestry community

Builder nets ease of use and sound control with this shaft wall alternative product.

In July 2017, North Carolina builder Fleming Homes started work on The Tapestry, a 99-unit townhome project designed for active adults in Garner, N.C. For the partition walls separating the townhome units, they used LP FlameBlock Fire-Rated OSB Sheathing in a UL Design No. 350 Type B assembly for a 2-hour partition wall that is fire rated on both sides.

Before this project, Fleming Homes COO Wayne Baker had used partition walls using shaft wall liner, commonly referred to as “shaft walls.”

CodeWatcher FlameBlock

FlameBlock is shown here on a multifamily project. The product can be used for UL Design No. U350 Type B assembly.

“We were looking for an alternative to the shaft wall application because they are so difficult and aggravating to build,” says Baker. “A dealer rep at BMC told us about the FlameBlock assembly as an alternative. The city codes council reviewed the plans and found them fire code compliant.”

The builder was also looking for a product that would help with sound control, which is a major concern for the active adult community. “The typical ‘active adult’ is a 55+ homeowner moving into a connected unit from a single-family stand-alone home,” notes Baker. “Many have never lived in a multifamily community. They are very worried about sound control.”

Recent product testing conducted by LP Building Products and Intertek, a product testing and certification company, showed that the UL U350 Type B assembly well-exceeded the code minimum for sound transmission with an STC rating of 62. Not only does this wall assembly carry an STC rating, it also provides greater design flexibility compared to the traditional partition wall assembly using shaft wall liner. In the UL U350 Type B assembly, the two-sided layer of LP FlameBlock sheathing eliminates the heavy, 1-inch-thick gypsum and associated hardware, resulting in labor and material cost savings plus a reduction in dead load when compared to shaft wall.

It also proved to be more cost-effective when working with sub-contractors and outside laborers.

“Shaft walls use fire tape. They’re extremely cumbersome to build,” Baker says. “Framers don’t like to build them so they charge you more per square foot just to build it. It’s just a more expensive system to use than the FlameBlock system.”

According to Baker, the installation went very smoothly. “Because of the ease of installation and the simplicity of the product, it saved us a lot of time. The process has gone much faster than the traditional shaft walls.”

The Tapestry is expected to be completed by July 2020 and will have five distinctive villas with craftsman-style architecture and stone accents. In addition to the townhome units, there will be a clubhouse featuring a card room, large stone fireplace, fitness room, and conference room that will serve as a gathering place for the community.

Baker says he plans to use LP FlameBlock sheathing on any projects that require a partition wall in the future. “Even the name ‘FlameBlock’ itself speaks volumes. If we can reassure these active adults that we’ve done everything we can for the safety and the fire rating and we use the resilient channel to cut down on the sound, we’ve met two of their biggest concerns.”

Sarah Caperton is OSB Product Manager, LP Building Products.