Disrupting the light gauge steel stud industry...

Its been a long time coming. Steel studs been widely used in non-combustible construction- interior and exterior, load-bearing and non-load bearing, shaft walls, demising walls, ceilings, soffits. These assemblies are well tested, predictable and for the most part, they perform as intended. But let's look at a couple things that conventional steel framing has not done very well.

1) Sound Transmission- Structure borne noise: where a structure is directly vibrated and the vibration is transmitted through the structure in all directions. Think of ringing a bell, banging a gong or clanging symbols as illustrations of how sound vibrations travel through a solid medium like metal.

Reducing the surface area through which the sound vibrations can travel is a key strategy in improving sound performance. Imagine how much quieter a gong might sound if it looked more like a doughnut with 50% of the surface area removed. That is a key to improving sound performance. The problem with reducing the surface area of the steel is that putting holes in the steel actually makes it weaker. In fact, the Northwest Wall & Ceiling Bureau (NWCB) published a technical document (#200-105) stating that "Notching, cutting or boring holes in non-structural light gauge metal framing members for the installation of MEP elements must take into consideration the effects to the structural integrity of the framing member", referencing The Steel Stud Manufacturers Association (SSMA) ICBO ER-4943P which is very specific as to the allowable size and location of punch-outs (see image below):

SSMA General Note #4 states: “When provided, factory punch-outs will be located along the centerline of the webs of the members and will have a minimum center-to-center spacing of 24.” Punch-outs will have a maximum width = half the member depth (d/2) or 2-1/2,” whichever is less, and a maximum length = 4-1/2.” The minimum distance between the end of the member and the near edge of the web punch-out = 10.” Engineering calculations performed by the SSMA have determined that punch-outs meeting these criteria will not compromise the integrity of the stud.”

Challenge- reducing the surface area of the stud web without weakening the stud.

Solution- by creating supplemental flanges, the surface area of the stud is greatly diminished while the strength of the stud is increased dramatically. This approach achieves approximately a 40% reduction in the surface area of the stud while increasing its strength by an average of 30%. An added benefit of this increased strength is that lighter gauge steel may be used to achieve greater limiting wall heights (further improving sound transmission class (STC) by as much as 8-10 points.

2) Steel is an excellent thermal conductor. While this may be beneficial when boiling water on the stove, the thermal conductivity of steel framing presents challenges when used in exterior walls due to a well documented phenomenon know as "thermal bridging". Through CONDUCTION, heat moves through the steel from the warm side of the wall to the cool side. In cold climates, this means that heat from the inside of the building is lost to the exterior as it flows through the studs. The result is that more energy is required to keep the building warm and comfortable.

Solution- by reducing the surface area of the stud, thermal bridging is reduced by an average of 35% (Source: RDH Building Science Laboratories Report No. 10935.000)

Through extensive hot box testing, RDH compared 6" conventional steel studs with 6" R-studs of the same gauge and spacing. On average, thermal bridging was reduced by an average of 35% and as much as 40%. This improvement in thermal performance may result in lower overall energy use <or> the use of less insulation required to meet local Energy Code requirements. In ASHRAE Climate zones 2 and 3, this has the potential to eliminate the need for 1 inch of exterior insulation (depending on stud spacing and a range of other variables). The use of 3D thermal modeling to determine the U-Value of the wall assembly and its applicability for a given climate zone will govern whether or not (or how much) continuous insulation (ci) is required.

3) Material usage- Over the past couple of decades many strategies have been employed to combat the issues of thermal bridging and sound transfer through light gauge steel framing. In sound assemblies, adding layers of gypsum wall board (GWB), resilient channel (RC) and acoustical insulation helped to mitigate the transfer of sound through walls. Remember the old saying "the walls are thin". Someone usually said that after hearing their neighbor's TV in an apartment or condo. The sound rating of the conventional wall assembly below is a STC 44 and it consists of 25ga studs @ 24" o/c with 2 + 2 GWB.

An alternative assembly consisting of 25gs R-studs @ 24" o/c with 1+ 1 GWB yields a sound rating of STC 49 using two less layers of GWB.

Imagine eliminating all of that gypsum wallboard a 15 story apartment or condo building.

Emerging technologies, means and methods, material science, automation and artificial intelligence (AI) are having a profound impact on industries like agriculture, manufacturing, automotive, electronics, fashion, retail, online dating, banking and more- and the construction industry is no exception. Modular construction, improved materials and increased efficiencies are improving energy performance, occupant comfort, environmental impact and even upending traditional cost models. Light gauge steel framing is only one of many parts of a building but incremental improvements on many fronts can add up!

To find out more about R-stud, visit www.rstud.biz. To learn more about m?dfacade visit us at www.modfacade.com