Limitations of Conventional Wood System
There are three major problems with use of all-wood conventional formwork systems.
1. High labor costs. The conventional formwork system is a labor-intensive system. Labor costs range from 30 to 40 percent of the total cost of concrete slabs.
2. High waste. Erecting and dismantling conventional formwork is conducted piece by piece. This causes breaking of edges and deformation of wood. It is estimated that 5 percent waste is generated from a single use of formwork.
3. Limited number of reuses. Number of reuses is the key to an economical formwork construction. Typically, conventional formwork is limited to five to six reuses. A limited number of reuses forces the contractor to use several sets
of formwork; this adds to the expense of formwork construction.
4. Higher quality of labor force and supervision. Conventional formwork systems work best with a high-quality labor force and adequate supervision. In areas with an unskilled or semiskilled labor force and minimal supervision, more sophisticated formwork systems are more appropriate.
5. Limited spans. Since dimension wood is low strength compared to that of aluminum and steel sections, it has limited use in applications where long spans are desired.