Types Of Pitched Roof Framing
Understanding how a roof is built in order to create a waterproof layer is essential to the design. Realizing that the roof is supported by outside walls, interior weight bearing walls, and the ceiling joists as part of the overall water-shedding capability will help in planning a roof overhaul.
Before construction of a pitched roof or any type of repair work, you have to factor in the age of the roof, the type of covering, and the climate of the location. In Colorado, the climate is generally considered semiarid in the lower elevations, with lower humidity and moderate precipitation, but the higher elevations will include lower temperatures along with more moisture.
Roofs are under a lot of pressure, so in order to stay intact and in place, a roof must be able to resist loads that are pushing both downward and upward on it. There are four main types of pitched roof designs with many variations and combinations:
Gabled – The roof slopes around a triangular extension of the end wall. This piece of wall is the gable.
Hipped – A hip is the joint between two adjacent slopes of a roof. Some complex roofs have several hips.
Shed – This simple roof has only one slope. It is commonly used on lean-to structures, such as additions.
Mansard – A modified version of the pitched roof that creates a spacious living area in the roof space.
See more here: All About Roofs: Pitches, Trusses and Framing
Best Wood For Construction of a Pitched Roof
The pitch of the roof helps to determine the type of roofing materials, but in general the wood that is used is dimensional lumber which is less expensive. Pine is a very common type of wood in framing, because it is soft, not so heavy, and easier to work with.
The following video provides an overview of the best wood for framing a pitched roof as opposed to wood used to build fine furniture:
The wood that is used as the horizontal member to span long distances in the framing process is many times engineered wood. Dimensional lumber can be utilized depending on the load and span, but there are times when the architectural design requires engineered lumber.
It is also known as composite or man-made wood and it includes a range of products which are manufactured by binding strands or particles of wood together with adhesives under intense heat and pressure. The consistency of the material quality is one of the key benefits, as the wood doesn’t generally shrink, warp, cup, crown, or twist.
Cost of Dimensional Lumber vs Engineered Lumber
It does cost more per lineal foot, but the advantages are mentioned here:
The manufacturing processes required for wood products add costs, making engineered wood more expensive per lineal foot than traditional sawn lumber. “The benefit is realized in total installed cost of the product,” according to Mike O’Day, manager of engineered lumber for Georgia Pacific. “The installed costs consist of material usage, and labor requirements for installation. Engineered lumber can speed installation time and reduce labor since they are lighter and can be spaced further apart than dimensional lumber. The result is typically a lower total installed cost per square foot with engineered lumber,” adds O’Day. Engineered lumber also reduces the number of call backs for builders. Squeaky, or bouncy floors are usually expensive to correct. Installations using engineered I-beams can significantly reduce callbacks related to this problem.
Read more here: Wood vs. Engineered Lumber
The use of engineered lumber has significantly increased, mostly due to the strength and consistency of the product, but it is also better for the environment. The fact that leftover pieces of wood can be used to make the product, there is little waste.