Engineering and Construction

Wood in panel form is advantageous for many building applications (Figure 3.28). The panel dimensions are usually 4 by 8 feet (1220 by 2440 mm).

Panels require less labor for installation than individual boards because  fewer pieces must be handled, and  wood panel products are fabricated  in such a way that they minimize  many of the limitations of boards and
dimension lumber: Panels are more nearly equal in strength in their  two principal directions than solid  wood; shrinking, swelling, checking,  and splitting are greatly reduced.

Additionally, panel products make  more efficient use of forest resources  than solid wood products through  less wasteful ways of reducing logs  to building products and through  utilization in some types of panels  of material that would otherwise be  thrown awayÑbranches, undersized trees, and mill wastes. Many wood  panel products are made largely  from recovered or recycled wood  waste, and panels made from rapidly  renewable vegetable fibers are also  available.

Figure 3.28 Plywood is made of veneers selected to give the optimum combination of economy and performance for each application. This sheet of roof sheathing plywood is faced with a D veneer on the underside and a C veneer on the top side. These veneers, though unattractive, perform well structurally and are much less costly than the higher grades incorporated into plywood made for uses where appearance is important.