Founded more than 40 years ago, Niles Bolton Associates (NBA) has designed projects in 49 states. The company is headquartered in the Buckhead area of Atlanta, with an office in Alexandria, Virginia. NBA has built a reputation as one of the nation’s most innovative design firms for sophisticated mixed-use communities.
The Use of LP® FlameBlock® Fire-Rated Sheathing
Between 2013 and 2018, the Alexandria office of NBA worked on two projects that used LP® FlameBlock® Fire-Rated Sheathing in the UL assemblies. Both projects had five floors of Type IIIA wood-framed residential construction over two levels of Type IA cast-in-place concrete.
Trellis House is a mixed-use, market-rate rental community near Howard University in Washington, D.C. Due to the proximity to the property line on one side of the building, 2-hour walls rated for exposure from both sides were required so the team selected to use the V337* assembly. Landmark College Park near the University of Maryland needed an easy-to-install, cost-effective means to provide a 2-hour rated exterior wall, and the team opted for the W408 assembly on this build. NBA principal Steve Gresham and project architect Kevin Cabitt trusted both assemblies featuring LP FlameBlock Fire-Rated Sheathing to accomplish the goals set before their team.
The LP FlameBlock Advantage
Both the W408 and UL V337 assemblies give architects greater design flexibility by helping reduce wall thickness compared to common alternatives and helping expedite wall construction. The assemblies use one sheet of two-sided LP FlameBlock sheathing and help reduce the amount of exterior gypsum required to attain the exterior fire resistance. LP FlameBlock panels have an Exposure 1 rating, which means that they can withstand normal exposure to moisture during construction. They also provide an excellent substrate for securely fastening exterior facing cladding.
“We were able to meet strict zero lot line fire codes using the V337 wall assembly with LP FlameBlock sheathing at Trellis House,” says Cabitt. “During construction, the windows were installed on one façade before the code officials requested the wall to be 2-hour rated for exposure to fire on both sides of the wall. After a quick examination of assemblies utilizing LP FlameBlock panels, we determined our needs were satisfied by the V337 assembly. Some wall assemblies would have required taking out the windows to do that, but not the V337 assembly. That saved a lot of time and money on the project.” Since Trellis House was built, LP has obtained approval of the UL V337 2-hour rated assembly, which provides a UL listing for this assembly. This makes approvals from building officials easier to obtain.
For Landmark College Park, the value came through ease of installation. “Overall, there was much greater construction ease with the W408 wall assembly compared to the UL assembly U301,” says Gresham. “The W408 assembly has fewer parts, so the installers can do a better job. It was also easier for us to determine that the fire-resistant portion was in place because of LP FlameBlock sheathing’s distinctive white color.”
*Formerly W408 Extended, now tested with UL designation