Know Your House: Components of Efficient Walls

Two of the biggest improvements of the industrial revolution were that the mass production of dimensional lumber for framing, along with the nail. Not only did those 2 products allow to be constructed by the thousands, but they led to a style of architecture. Houses were constructed of rods, instead of heavy timbers or masonry.

From the early 19th century, with the start of stick-built homes, balloon framing became the standard. With this kind of framing, the exterior walls are constructed of wood studs which begin in the base’s sill plate and cease in the highest top plate. The wood studs which make up these partitions can therefore easily be 18 or more feet in length. Balloon framing died out only because of the unavailability of wood studs of such long spans.

Everything came about is stage framing, the process used to build wood-frame homes today. It depends on each story of a house being constructed as a stage so the exterior walls are constructed of wood studs no longer than about 10 or 12 feet.

Here’s a peek at a basic and traditional platform-frame exterior wall, as well as a version of this system which uses far less substance.

Related: Insulated Concrete-Form Construction | Post and Beam Construction

Bud Dietrich, AIA

Fundamental 2-by-4 framing. The most common way of building a wood-frame exterior wall is to use 2-by-4 wood studs spaced 16 inches in the center of one stud to the center of another. These studs are then fastened to a 2-by-4 bottom plate and a double 2-by-4 top plate. Corners have three studs so that there’s always a surface to fasten another material (drywall, sheathing etc.) onto.

Wood-frame walls like these can be easily constructed on the wood floor deck and tilted into place. Once tilted into place and made plumb (straight up and down), square and even (the corners are at 90 degrees or a different angle, based on the layout), these walls are firmly fastened to the ground structure.

Other than the framing needed for openings, like for doors and windows, the closing structural part of a wood-frame wall is the outside sheathing. Sheathing, usually OSB (oriented strand board) or plywood, is traditionally employed in most homes to help make the structure rigid so that the house doesn’t twist or rack.

This type of sheathing also gives a surface that siding could be attached to. You will find other substances, such as rigid insulating material, that can be used instead of OSB or plywood. Whenever these substances, which will increase energy efficiency, are used, structural rigidity will be accomplished through bracing or specific fasteners or other.

Bud Dietrich, AIA

Openings for doors and windows. To accommodate doors and windows, the framings of walls have framed rough openings. In reality, most manufacturers produce doors and windows that fit within a particular rough opening. Knowing the exact window and manufacturer is important in the planning stage so the carpenters build the walls as necessary.

The parts that form a rough opening are the king stud, jack stud (I would love to understand the origin of those terms), header, sill and cripple. Each piece has a job to perform. For example, the jack studs encourage the header, and the header is used to span the opening.

And it should be noted that using a typical 8-foot ceiling, the conventional 80-inch-high doorway fits neatly into a rough opening created out of a double 2-by-12 header. With the header positioned tightly against the underside of the double top plate, then the rough opening steps around 82 inches high. Even though this isn’t exactly the most effective use of substance (the header is often considerably bigger than required), it has become the standard because of its simplicity.

Bud Dietrich, AIA

Optimized framing. Wood framing began when wood was abundant and inexpensive, and a house’s thermal efficiency was not a consideration. As a result, traditional wood framing utilizes far more substance than it needs to, and also the typical 3.5-inch wall thickness doesn’t allow for as much insulation as is needed to get a thermally efficient residence.

More advanced framing techniques now use 2-by-6 wood studs instead of 2-by-4s, a single top plate and 2 studs instead of 3 stud corners. The advantages of utilizing 2-by-6s include:
Increased cavity space to accommodate more insulationStud spacing that’s 24 inches instead of 16 inches on center, resulting in less total materialTo ensure structural integrity and accommodate the installation of materials like drywall and sheathing, particular clips and connectors are developed for this particular framing approach. For example, alloy splice plates can seam together the only top plate.

Optimized framing additionally uses headers which are sized as needed to length door and window openings. As this has the advantage of reducing material costs, in addition, it achieves a distinct architectural appearance, as taller doors and windows could be had.

Next up in this series: the roof structure and how that defines the structure of your property.

More in Know Your Own House:
Post and Beam Construction
Insulated Concrete-Form ConstructionWhat Makes Up a House’s Foundation
What Makes Up a Floor Construction

See related