Unit 1 Types of Construction Residential and Light Construction • Heavy Construction • Prefabricated Building Units • Green Building • Specialization in the Trade

Residential construction is a category of light construction. Residential construction is a type of light construction that includes houses, condominiums, and small multi-family dwellings (apartment buildings). See Figure 1‑1. Residential and light construction employs the greatest number of carpenters. Other light construction projects include small- to medium-size commercial buildings such as stores, restaurants, and warehouses.

In platform framing, each floor unit provides a working platform for the walls above. The framing method used for most light construction is platform framing. Platform framing consists of studs, plates, joists, bracing, and other structural members. Studs for a platform-framed structure are one story high. Double top plates over the studs support the floor joists for the next level. A subfloor is fastened to the joists, providing a platform for the next level. See Figure 1‑2.

Post‑and-beam construction is characterized by exposed members, in this case redwood members, that also serve as the basic structure of the building. Post‑and‑beam construction is another wood‑framing method. As its name implies, post‑and‑beam construc-tion relies on posts and beams for its basic structure. See Figure 1‑3. In most cases the beams are exposed, providing an attractive and open appearance to the building interior.

Stone‑veneer foundation and chimney combined with resawn redwood siding create an attractive effect for the house. In brick‑veneer or stone‑veneer construction, brick or stone is used as an outside covering (veneer) over a conventionally framed stud wall. See Figure 1‑4. Brick-veneer and stone-veneer buildings give the appearance of having masonry exterior walls, but the primary support is provided by wood and metal structural members.

Reinforced concrete is typically used for most heavy construction. Most heavy construction uses reinforced concrete. Reinforced concrete is concrete that contains steel re-inforcement (rebar) or fiberglass reinforcing rod to strengthen it. Large office buildings, hospitals, bridges, freeways, and dams are types of heavy construction. See Figure 1-5.

In monolithic concrete construction, each major element of a structure is cast as a single piece. Monolithic concrete refers to the traditional method of concrete construction in which each major element of a building, such as a wall, is cast as a single continuous piece. Monolithic concrete construction is primarily used for small- to medium-size buildings. See Figure 1‑6. Prefabricated forms are erected and/or wood forms are built to the shapes of the walls, beams, columns, and floors of the building. Rebar is placed and secured inside the forms and concrete is placed (poured) in the forms. When the concrete has set (hardened) sufficiently, the forms are stripped.

Most multistory commercial buildings have a steel framework. Most high‑rise buildings (skyscrapers) and some small- er buildings are erected with a steel framework. See Figure 1‑7. In the past, carpenters built wood forms around the steel framework and concrete was placed in the forms. Today, however, precast concrete units are lifted into place by crane and fastened to the steel frame. The use of precast concrete units is more efficient and less costly than the older construction method. In many cases, carpenters are involved in attaching the precast concrete units to the steel framework.

Precast concrete wall panels of a building are raised into position with a crane. In tilt‑up construction, concrete wall units are cast on the floor or transported to a job site after being cast at a precast plant. The wall units are raised into position with a crane and properly braced. See Figure 1‑8. In lift‑slab construction, floor slabs are stack‑cast around columns at the first floor and raised into place by hydraulic jacks. Carpenters perform key operations in both tilt‑up and lift‑slab construction.

A fully automated assembly line is used to construct panel wall sections. In addition to residential structures, light commercial structures such as office buildings and schools may be constructed with panel systems. The basic units of panel systems are the wall sections, which are constructed on an automated assembly line framing station. See Figure 1‑9.

Carpenters install prefabricated panel wall sections. When delivered by truck to the job site, the wall sections are installed by carpenters. See Figure 1‑10. In addition to wall sections, a panel system may also include a roof system that includes roof trusses. Floor sections may also be provided, although the joists and subfloor are typically installed on the job site.

An exterior wall panel is lifted after completion and prepared for shipment to the job site. In an open panel system, the outside surface of the exterior wall panel is covered with sheathing or insulation board, but the inside surface of the wall is left exposed (open). In many cases, finish siding and completed window and door units are also installed at the man-ufacturing facility. See Figure 1‑11. The plumbing and electrical systems are installed on the job.

Sustainable design and construction yields environmental, economic, and health benefits for the builders and the surrounding community. Green building, also known as sustainable design, refers to building design and construction methods that efficiently use materials, energy, water, and other natural resources. In comparison to traditional design, green building places a greater emphasis on occupant health and productivity; efficient energy, water, and other resource utilization; and reducing the overall impact on the environment. Green building principles are achieved through optimum building location on a building site and better design, construction, operation, maintenance, and removal—in other words, the complete building life cycle. See Figure 1-12. The green building initiative was developed due to concerns about diminishing natural resources, increasing pollution levels, and other factors that may cause harm to the environment.

LEED® certification levels are determined by accomplishing certain goals within each of six certification categories. Voluntary rating systems provide standards and guidance for green buildings to architects, engineers, construction managers, lenders, and government off-icials. The primary rating system for green buildings is Leadership in Energy and Environmental Design® (LEED®). LEED certification offers confirmation and proof that a building meets its environmental goals. LEED certification levels are based on a point system ranging from 26 points to 69 points. LEED certification levels are as follows: • Basic—26 points to 32 points • Silver—33 points to 38 points • Gold—39 points to 51 points • Platinum—52 points to 69 points Six categories with various certification criteria are used to determine the LEED certification levels. See Figure 1-13.

Mass production methods are used on new subdivision housing tracts Mass production methods are used on new subdivision housing tracts. Separate crews install the foundations, wall and roof framing, exterior trim, and interior trim. Improved production and scheduling methods in con-struction have led to increased specialization of work. On housing tracts, for example, a large number of homes are constructed at the same time by crews of carpenters specializing in various divisions of carpentry work. See Figure 1‑14. One crew of carpenters installs all the foundations of the houses while other crews separately place the floor units, walls, roofs, and ceilings.