Choosing the right timber for your project is the key to success. It must be strong and durable enough for your needs and give you the kind of finish you want.
There are a lot of names, codes and abbreviations used in labelling timber. Here’s our simple guide to the ones you’re most likely to see.
The most common terms are softwood and hardwood, which are sometimes abbreviated to SW (or SWD) and HW (or HWD).
Softwoods come from conifers or Pine trees, with the most common being plantation radiata Pine. Softwoods are lower-density and generally lighter to handle and easier to drill and cut.
Hardwoods come from flowering trees, including many native eucalypts. They are dense timbers that are stronger and more naturally durable. They can be extremely heavy and are more challenging to work with.
One example: treated Pine decking is a softwood, while Merbau decking is a hardwood.
The timber you buy will have been sawn and milled in one way or another. There are various terms for the level and type of finish that results, including:
There is a range of processes applied to different timbers for different purposes. They include:
Timber is also treated differently according to its intended use. Treatments include:
The “H” or hazard rating of timber relates to the level of timber perseverative treatment. The higher the number the greater the level of treatment applied to the timber. The ratings are:
These ratings tell you how much load timber can take. This then relates to the allowable length of spans of bearers and joists for decks and house flooring and situations such as cantilevered balconies.
There are two rating scales. The F scale is primarily used for hardwoods, while the MGP (machine-graded Pine) classification is used for Pine.
If you are working with plans that specify an F or MGP rating do not substitute one for the other without seeking professional advice.
F ratings start at F1 for the weakest timbers. Examples include:
Not all the timber we use comes straight from a tree. Manufactured timbers, also known as engineered timbers, are increasingly used for a broad range of applications.
Their manufacturing processes can maintain consistency in smoothness, strength and other properties, whereas natural timber may be more variable.
Here are some of the manufactured timbers you’re most likely to encounter:
Check out our step-by-step guides, which include How to build a deck, How to build a retaining wall, How to build a planter box with bench seats and How to build timber screening. And please let us know if we can help with your project – we'd love to help you get a fantastic result for your home.
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