Methods of New-Home Construction
There are plenty of ways to build a new home, but which method of construction is right for yours?
The best building method to use for your new home is an important discussion to have with your builder – and your architect, if you’ve hired one to create a custom home plan.
While most new homes in the U.S. are framed on site using conventional lumber (traditional stick framing), there are other ways to build a new home, including using light-gauge steel, modular homes that are built indoors and homes built with structural insulated panels and homes built with concrete. Below is an overview of the most common methods of new-home construction. Equipped with this information, you and your builder are ready to decide which method of construction is the best approach for your new home.
• Traditional Stick-Framing
What most likely comes to mind when you envision a new home being built is something called “stick framing.” This building system takes its name from the fact that workers assemble the skeleton of the home – wall studs, floor and ceiling joists, and roof trusses or rafters – stick-by-stick, usually on the jobsite, using lumber cut to varied sizes. This includes the familiar “2 by 4,” which has dimensions of roughly two inches by four inches.
Stick framing is also sometimes called platform framing, because workers build the first-floor platform on the foundation. This is followed by framing the first-story walls, adding the second floor platform, then building the second story walls, and ultimately adding the roof framing.
In a small but growing number of homes, wall panels are stick-built of wood but assembled in a manufacturing plant and then trucked to the building site and assembled there. Proponents of this system, referred to as panelization, point out that entire wall systems can be constructed in a factory setting, away from weather and rain. Whether walls are stick-built on site or constructed in a factory, the overall wood-framed structure of the home is similar.
Once the structure of the home has been framed, the so-called mechanicals – including pipes, wires, and ducts – are routed through walls and floors. Insulation is then packed between the framing members of exterior walls. Following an inspection, inside walls are typically covered with drywall. The exterior of the home is covered with a weather-resistant cladding such as stucco, siding, or brick veneer.
The American home building industry has used this system for decades. As a result, new-home construction has become standardized around this time-tested method of stick-built framing.
According to the National Association of Home Builders (NAHB) Research Center, stick-built homes account for more than 90 percent of all new homes built in the nation each year. Everyone involved in residential construction – builders, carpenters, other trade contractors (also referred to as sub-contractors) and architects – thoroughly understands this building model. In addition, an extensive building material supply chain has developed across the country to support this method of new home construction.
Despite its near ubiquity, stick framing can have some drawbacks. If framing lumber is too moist, it can shrink and warp as it dries and that can cause drywall cracks. And the multitude of spaces between framing members can be difficult to insulate and air seal correctly using standard fiberglass batts. There are solutions to these issues – such as using properly dry lumber and one or more insulating systems that are installed with care – to ensure a quality home.
Although this site-built stick frame method of constructing new homes using wood and lumber clearly dominates, there are other ways to build the structure of a home. These methods can also provide additional energy efficiency or better resistance to storms. The alternatives include steel, modular, structural panels, and concrete. Here’s how each compares to the traditional wood-framing method of construction outlined above:
• Light-Gauge Steel
Think of a stick-built home, but with the sticks made of metal. The advantage, of course, is that steel won’t burn, shrink, rot, or provide food for termites. When properly engineered, steel can be stronger than a wood frame. And because it doesn’t shrink or warp, there is little worry about drywall cracks.
Light-gauge steel is used in commercial buildings for interior partitions so there’s a well-established supply chain. The lower market share for steel-framing is mostly due to price and familiarity. A steel home costs more to build – around 3 percent more according to most estimates – and few residential builders have the tools or skills needed to work with it. (Note: All costs in this article are very rough averages. Building materials fluctuate in cost from month to month, and also vary from region to region.)
Steel studs also pose different challenges for plumbers and electricians, and because steel conducts heat, the insulator has to take steps to isolate the frame from the sheathing – usually by wrapping the home with rigid foam insulation.
• Modular Homes
A modular home uses conventional stick framing and must satisfy the same building codes as a site-built home, and holds its value about as well. (Don’t confuse it with a mobile home, which is a depreciating asset built on a steel chassis that falls under the Federal HUD building code.) Modules are built in a factory and finished on the inside. They’re trucked to the site and set in place with a crane. The local builder knits them together and adds finishing touches, like decks.
Although you’ve probably seen a modular home – usually two halves of a simple box – rolling down the highway, they’re not the whole story. Modulars come in all quality levels and price points, and some manufacturers combine custom-built modules in different ways to create complex designs, that include cathedral ceilings and other popular architectural features.
In principle, the factory environment offers better control over everything from the framing to the insulation, but in reality the product varies. The quality offered by some modular builders can equal site-built homes and some firms have designed “green” homes. Other modular builders have been known to cut corners – for example, with thin interior walls that offer little privacy from noise. Ask lots of questions, get references, and scrutinize the product specs as carefully as you would with any home. Expect higher quality to carry a higher price tag.
• Structural Insulated Panels
A Structural Insulated Panel, or SIP, is a sandwich of rigid foam insulation between oriented strand board (OSB) that results in a structural panel. SIPs come with pre-cut window and door openings as well as conduit for electrical wiring. They’re used for walls and ceilings, and can be combined to create nearly any home design. Specially trained crews assemble them on the jobsite. They’re often used to cover a traditional timber frame, or post-and-beam structure, but they can also be self-supporting.
A SIP home tends to be well insulated and draft free, so it needs less energy to heat and cool than a typical stick frame. As such, you may need a smaller heating and cooling system.
While the materials for the building shell will cost more than a wood frame, builders who offer this system claim that overall cost roughly equals stick framing, and may even be lower. That’s because it takes less labor to assemble the panels, and the insulation is already in place.
Concrete is probably the world’s most-used building material, but aside from foundations you will only see it in a minority of U.S. single-family homes. In homes that do use it, walls are built from either concrete masonry units (CMUs) or insulated concrete forms (ICFs). Wood framing is used for floors, ceilings, interior walls, and roofs.
Concrete Masonry Units: CMUs, are hollow concrete blocks stacked on site and covered on the inside or outside with foam insulation board. Because the blocks’ thermal mass slows the transfer of heat, the inside of the home stays cooler on hot days. Not surprisingly, they’re most popular in the South and especially Florida, where CMU homes are priced competitively with wood framing.
Autoclave Aerated Concrete (AAC) block: A variation on the concrete masonry units above, AAC is a mix of Portland cement, aluminum, fly ash (a waste product from coal power plants), and other additives. Chemical reactions between the materials form microscopic air bubbles that act as insulation. Costs will be somewhat more than standard CMUs.
Insulated Concrete Forms: ICFs are rigid foam forms or Lego-like blocks that are assembled on site and then filled with steel reinforcing rods and concrete. The forms stay in place to serve as the home’s insulation. ICF walls offer thermal mass and provide insulation values of up to R-25 – higher than most wood-framed walls. That makes them a good fit for any climate.
About 30 ICF manufacturers serve the U.S. market, according to the Portland Cement Association. Costs are at least 2 percent to 5 percent more than a wood framed home of similar design, but the actual price depends on the local market and could be much higher.
What sets an ICF home apart is its sheer mass. Concrete stands up well to high winds, so ICF manufacturers and builders position the system as a good choice in hurricane-prone areas. (But remember that, in most cases, hurricane damage starts with roof uplift, and the home still has a wood framed roof.) The heavy walls also deaden street noise so, when fitted with quality windows and doors, the home should be quieter than a wood frame. And concrete also doesn’t get eaten by bugs.
As a next step, discuss a method above that interests you with your builder. If you decide to use a method other than traditional stick-building, make sure that your builder and his trade contractors have strong experience in the type of construction you chose. If you’re working with an architect, and want to build using a method other than stick-framing, make sure your architect is also experienced in the type of construction that you elect.
What’s the common element of each of the construction methods above? In the hands of an experienced builder, architect and team of trade contractors, each will provide you with a high quality, energy-efficient and durable new home that’s ready for many years of enjoyment.