Durability

Durability

In human history, wood has always been an important building material. There are many examples of wooden buildings from around the world, including China, that have lasted for centuries in all types of climate. They provide evidence that wood construction can last virtually forever, providing it is designed and built properly to meet specific climatic conditions, and maintained appropriately over its full life cycle.

Design, specification, treatment and maintenance need to be carefully considered for the different climatic conditions. Appropriate design, material selection, construction, and maintenance will ensure that wood is safe from the decay and mould associated with exposure to excessive moisture, as well as from the termite infestations.

Durability depends on protecting wood from excessive moisture. Building envelopes should be designed to prevent water vapour condensation within envelope cavities and to allow any dampness to dry out. In wet climates, more steeply sloped roofs, large overhangs and rain screens can be used. As with any building system, the building envelope must be sealed against rain penetration around windows, doors, and other exterior wall openings, including roof penetrations and balconies.

In areas with termite hazard, effective prevention and control can be achieved with appropriate design and construction practices. In recent years, multiple lines of defense have been developed and integrated into modern wood construction to ensure moisture and termite resistance.

Exterior wood products used for decks and other landscaping projects are either made from naturally durable wood species, Western red cedar and yellow cedar, or pressure treated with chemical preservatives.

Strict regulations on environment and human health ensure these chemicals are benign to humans but resistant to insects and fungi. Good design, workmanship, and maintenance are also critical for prolonging the service life of outdoor wood products.

Modern wood frame construction has a good record of durability

Modern systems of wood frame construction also have a good record of durability. This building type has a long history in Europe and North America, and there are still houses standing from the original developments. Many North American and European wood houses are over a hundred years old.

Progress in design, material use and treatment, construction techniques and maintenance have been made in recent decades to make sure that wood buildings can endure indefinitely.

A survey on wood building service lives

Buildings are rarely demolished because they are beyond repair, or have
become structurally unsound. Generally it is to make way for a larger or
more modern building. Simple to maintain and repair, wood buildings
are easily renovated to adapt to new requirements. At the end of their
economic service life, they can be demolished, with recovered materials
being reused, recycled or used as biomass energy.

EXAMPLE FROM JAPAN?????????????

Liuhe Temple, Hangzhou, over 1,000 years old
Stave Church, Norway, from 1150, post and beam structure
Distribution of 94 non-residential buildings by age class and structural material