There are a huge number of materials that are used for outdoor furniture. Metals, such as galvanised steel and aluminium, are often used. Another common material used for garden furniture these days is plastic, such as uPVC. Each has certain advantages and disadvantages. However, many Australians still prefer the traditional feel of wood. Along with the finish of timber products, the internal structure of the wood should be considered before one type is chosen over another for outdoor furniture. Simply put, some timbers are better at lasting when they are outside. What should you be looking at when selecting the right sort of timber material for your garden furniture?
Understanding Soft and Hard Timbers
Softwood is a widely used term, but it can be a confusing one when you are choosing between different timbers for outdoor furniture. This is because hardwood and softwood, although being distinct groups, are not split according to how hard or soft they actually are and, consequently, you cannot rely on either term for the purpose of selecting a suitable timber for garden furniture. For example, despite being a hardwood, balsa has a very soft feel which might sound comfortable for an outdoor bench seat, but it would not last long outdoors and wouldn't be strong enough to sit on. Basically, hardwoods have more pores in them than softwoods and are not necessarily harder, so don't be put off thinking they might be uncomfortable, nor that softwoods are not durable enough for constructing outdoor seating.
The Internal Structure of Wood
Inside a trunk, there are two main parts of a tree which form the wood that could be used for furniture making: the sapwood and the heartwood. Sapwood is generally full of natural starches, which means that it is not durable enough for the purpose of making outdoor furniture. On the other hand, heartwood is widely used to make all sorts of outdoor timber products. Unless specially treated, sapwood should be avoided for exterior seating and tables.
In Australia, the expected life of a timber when used outside is given according to its class. Class one offers the greatest level of durability, and if you make exterior furniture from it, then you can expect around 25 years of continued use. Class four is the least hard-wearing, and although it is not unsuitable for garden furniture making, the expected life of any items that are constructed from it will be much lower. This rating system is not a guarantee of wooden furniture's durability against weather and infestation but is more of a reflection of known past performance of the timber type in a variety of outdoor settings. It can only be used as a guide, therefore.