RESTORATION OF HISTORICAL BUILDINGS
Wood is perfect structural material. Let s compare wood with concrete and steel which are superior products of present technology.
Wood has high supporting force
. 1 kg wood supports load more than 1 kilograms concrete or steel. 250 meters spans can be passed by wood without using columns. Steel can not be used in such constructions since it is heavy.
Wood is resistant against natural conditions and earthquake
Wood has the highest grade with respect to durability against weather conditions and chemicals. According to British standards, service lifetime of wooden posts which are used in electricity and telecommunications lines is 50 years, wooden fillers have 50 years service lifetime in water cooling towers and service lifetime of wooden road bridges is 50 years. Service lifetime of concrete and steel has almost life time in these areas. Carbonation problem has dealt a big blow to reinforced concrete which is believed to have indefinite service lifetime.
Wood has high resistance against fire
Despite common opinion, resistance of wood against fire is higher than concrete and steel. Recently In USA places where great crowded people will present are built as wooden carcass against fire hazards and in Germany steel constructions are coated with wood because of same reason. Research and compiled statistics regarding with fire expressly points out that wood which is used as supporting material is one of most reliable material. Reason for start of fire is never wood and amount of resistance of wood against great fires can be exactly calculated because of heat impermeability and carbonization. Wooden structures can be designed to resist fire for 30-90 minutes. However bare steel constructions can resist to normal fire for only 10 minutes (because of high expansion coefficient) and structure may collapse suddenly without warning.
This property, requirement of least energy for production and processing ( one fifth of aluminum with same amount), to be able to be recycling and superior insulation problems make it to be material which responds to environmental and energy problems of our era with best manner. Despite known issues, use of wood provides survival of forests. Hence forest areas increase continuously in countries using wood more.