What wood is best for your exterior project? What is the Most Durable Wood, what are the best types of hardwoods?
We have compiled a series of league tables to help compare and rate the properties of wood. All of our assessments are based on kiln dried timber (with the exception of the Green Oak and the Season Oak) starting from sawn, square edged boards.
more can be read on this here: https://www.wooduchoose.com/blog/wood-durability-league-table/
We have also searched the web and found more interesting articles for you to read:
We’ve put together some resources about Timber Durability to help you choose the best timber for your gate or garage door, or whatever you’re looking to make.
The Timber Durability chart contains 5 classes of timber, with each class determining how long each timber listed will last – these are all to BS EN 350-2:1994 – Durability of wood and wood-based products. Natural durability of solid wood. Guide to natural durability and treatability of selected wood species of importance in Europe.
The Timber Durability Database is a table of durability grades/ratings by wood type, with images to match.
Different woods have different natural resistance to attack from destructive organisms such as wood-decaying fungi and wood-destroying insects. Irrespective of the wood, sapwood generally has no resistance to biological attack, while the heartwood’s natural resistance varies from poor to very good, a property that only becomes apparent when the wood is naturally exposed primarily to moisture.
Heartwood comprises inactive wood cells. The openings between the fibres that occur in sapwood and that allow water transport are closed in heartwood and no longer function as transport routes. Heartwood tends to be quite resistant to water transport, except in end-grain wood. Sapwood commonly sucks up significantly more water than heartwood in all directions.
Consider a tree and your business as a machine. The tree is essentially a machine for fixing solar energy. To do that it functions as a pump that has a plumbing system to get water (and lots of it) up to the factories, the leaves, where carbon dioxide and water are combined into sugars, thus fixing the energy of the sunlight. The process is not very efficient, perhaps just 2% of the solar radiation is fixed, much of it being reflected back into space, and of course all the other living cells in the tree are busy releasing carbon dioxide. The sugars synthesized then have to be transported down the tree to supply all the living cells that make the tree work, like growth, roots, new leaves etc. This done by the inner bark and by horizontal cells that move food inwards (rays).
When buildings are designed with local climate impacts in mind, wood buildings can last for centuries. Wood has the ability to absorb and release moisture, and is resistant to many of the chemicals and conditions that adversely affect steel and concrete, such as corrosive salts, dilute acids, industrial stack gases, sea air, and extreme climate variances.
When used in tandem with proper envelope design, building with wood can reduce future maintenance and repair costs. Good design also ensures that wood materials last and weather well in various climates, including those with high humidity, frequent sun, and heavy rain.
In order to determine the suitability of different timbers for given applications, we use a rating called timber durability. Each timber is assigned a class from one to five which reflects the ability of that timber’s heartwood to resist decay and infestation by insects. In other words, how long will a timber last? It does not consider the lifespan of the sapwood for any species as all sapwood is rated as a class five, meaning not durable. Durability classes cannot take into account local conditions such as temperature, moisture, weather, physical stress upon timber, and competency of installation, but they do give a good guide as to how long any type of timber will last.
Timber Durability Classes. There are five different classes of timber durability, as defined by TRADA, The Timber Research and Development Association, ranging from class five to class one, where class five is consider not durable and class one is considered very durable.
Durability is a measurement of how long specific species of timber would last if a 50mm x 50mm cross section was left in the ground unprotected.
An untreated Oak beam, which is classed as 'durable', for example, will last 15-25 years depending on environmental conditions.
Due to modern advanced treatment techniques the durability of timber in construction is now far superior. Architects are able to create timber structures with the high performance and efficiency required for the 21st century. In an age of urbanisation, there is a need for fast and sustainable construction methods that bring a sense of nature into the home and workplace environment. Consequently, wood is undergoing a renaissance in the architectural industry, being recognised as a key constituent in the palette of materials that architects have to work with in today’s world.
More can be read on this here: https://www.wooduchoose.com/blog/wood-durability-league-table/
Biew our wood database
Posted on Wednesday 08 September 2021 at 11:46
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