Conventional framing options for most residential buildings in the United States are lumber framing. However, Light gauge steel (LGS), is slowly coming to light as an option for framing residential buildings. Some of its noticeable properties are;
- Flexible in design
- Performs well in natural disasters
Notwithstanding, LGS is struggling to replace lumber as a residential framing option, mainly because it is expensive and because of the poor thermal resistance of steel.
In this case, if you are caught in between these crosshairs, the best thing for you to do is contact a structural engineering consultant or a structural engineering firm. They would help in picking the best option for you, according to your budget. However, budget aside, the best framing option must be the best in the following:
- Behavior in earthquakes, fires, and floods
- Saving energy cost
After considering the above factors, you must then arrange these factors in order of your preference. In other words, which is most important to you. This article gives you the bases to make your decision.
Because of the susceptibility of wood to moisture and termite infestation, the durability of wood is often a point of interest. However, wood can absorb moisture and release moisture in the same manner, this ability would allow the wood to be good enough in climates with high relative humidity.
Although the ability of wood to release moisture is a plus, it needs enough time to release moisture. In this case, if it withholds its water content for a long time, wood would damage. Not to mention its affinity with termites.
Notwithstanding, wood-framed buildings can have a long lifespan. There are examples of long-lasting wood-framed buildings.
Light gauge steel
Steel, on the other hand, is very durable. The non-porous and inorganic nature of steel prevents it from being affected by mold or rot. This is because steel cannot absorb water and therefore cannot suffer moisture-related damage. However, when there is an exposure of steel to water and air, corrosion can occur.
Behavior in earthquakes, fires, and floods
There are examples of wood-framed buildings in seismic zones, however, these buildings are braced with lateral load reinforcements to minimize damage. Bracing can be achieved by installing shear walls. Although there are other forms of earthquake-resistant design, shear walls will ensure the transferring of forces to the foundation of the building, usually concrete.
One major con of wood or lumber framing is its very poor fire resistance. Pines and Firs are the most common tree species used for wood-framing, because of their economic value. However, their soft and hardwood ignite, with the former igniting and spreading flames faster than the former.
Although fire-resistant materials can be incorporated into the design of wood-frame structures to improve its fire resistance.
Additionally, in areas vulnerable to flooding, if wood framing must be material of construction, its design must include flood-resistance measures. Wood is susceptible to water-related damages like mold and rot. Some flood-resistant measures include;
- Applying water-repellent paint to the frame
- Using Expanded Polystyrene (XPS) insulation boards
- Spraying high-density closed-cell foam into stud bays
light gauge steel
Generally, the stiffness and design flexibility of steel makes it a better option for earthquake resistance. The lateral damage a building can suffer is a function of the building’s stiffness. Whereas, the design flexibility of steel ensures multiple seismic framing options as opposed to the lumber-framing limitation to shear walls.
Some of the seismic framing options for steel include;
- Flat-strap X-bracing
- Steel sheathing.
Admittedly, unlike wood, steel does not ignite a flame. And can sometimes act as a barrier to fire spread. However, at temperatures above 5500F, the strength of steel begins to deteriorate. Unfortunately, residential fires, sometimes rise to 1,1000F. And studies show that at this temperature, about 50 percent of the yield strength of steel is lost, which can lead to buckling.
Notwithstanding, there are fire-resistant measures capable of blocking of the frame from direct exposure to fire.
In areas susceptible to flood, galvanized steel can be so important. The protective zinc coating of galvanized steel acts as a barrier to moisture and its related damages. However, in the presence of salt or alkalis and prolonged water contact, galvanized steel will lose its coating and can corrode.
As we can see, LGS seems superior to lumber in many aspects. Steel is durable, in the sense that it doesn’t form mold or rot in flood-prone areas. In seismic prone areas, the strength and design flexibility of steel makes steel a better option for resisting earthquake loads.
Notwithstanding the cost of steel, the strength of steel means fewer materials can be used, which can save cost on materials. However, steel has its weaknesses, its tendency to collapse or buckle at high temperatures.