Timber is very popular in construction, and you’ll find it used in the form of timber fence panels, timber decking, and even decorative timber cladding. There are many types and forms of timber, and to help you understand we’ve put together this comprehensive guide.
What is Timber?
Timber is wood that has been cut and processed for use in building, furniture making and carpentry. Timber is usually sorted into three purpose categories: construction timber, finishing timber and decorative timber. There are also two types of timber, hardwood and softwood.
What is the Difference Between Hardwood and Softwood Timber?
As you might guess from the name, hardwood is denser and therefore stronger than softwood. Hardwood is typically derived from deciduous trees (lose their leaves annually) and softwood comes from conifers (keep their leaves year-round). Hardwood is preferred for construction timber, timber decking or fence panels. Softwood is typically used for decorative timber but can be treated to have the strength of hardwood.
| Hardwood | Softwood |
| Distinct wood grain | Less pronounced wood grain |
| Scratch and chip resistant | Easier to scratch or chip with a chisel |
| Denser and heavier per cm³ | Less dense and lighter per cm³ |
| Slow growing | Fast-growing |
| More expensive | Less expensive |
Is Oak Hardwood or Softwood?
Oak is a very popular hardwood and provides exceptional strength and durability, that’s why so many people buy timber fence panels and timber decking using oak. Other popular hardwoods are walnut, beech, maple, and ash.
Is Lumber the Same Thing as Timber?
Lumber may sound like a synonym, but technically defines wood that hasn’t been processed or treated and still has its bark. When timber is processed, it can be treated with preservatives to help prevent rot or insect damage. You’ll know if it has been treated if it has a class and a number in is technical specifications. More on that later.
Timber Terminology
Looking to buy timber online? You’ll have to learn the following terminology to be able to tell its size and specifications at a glance.
Grade
This refers to the strength and/or quality grade of the timber, and you’ll find a lot of timber online is graded using different standards, depending on the wood and its origin. The most common is the Canadian Lumber Standard, or CLS. Grades C16 and C24 mean the timber in question is a load-bearing timber, with the latter being the stronger.
When building timber decking or shelving, the load bearing grade will be important, but for skirting boards or timber fence panels, not so much.
Edge Finish
This is how the edge of the wood is presented. Rough and planed finishes refer to how smooth the finish is. As for the shape, square edges are most common, but rounded edges and waney edges are commonly put up for sale.
Material/Tree
This is the tree species that the timber was processed from. If the tree is not in the product name, then you’ll find it in this part of the product specification. The tree species matters if you are looking for a particular colour/aesthetic or need very specific qualities (e.g. strength and longevity) met for your construction project.
Stain
This is an aesthetical treatment added to the wood to change its colour whilst preserving the grain and natural characteristics. Usually this is provided as an optional extra, as you can stain the timber anytime by yourself.
Treatment
The type of process the timber has undergone to enhance its durability, strength, or resistance to pests. There are 4 classes of treatments, optimised for particular use cases.
UC1 timber has been treated to primarily protect against wood boring insects like woodworm and termites. This wood is for indoor use only, as it has few protections against moulds and funguses.
UC2 timber is a step up from UC1 and is used for interior constructions where there is risk of damp and moisture. It offers similar protections against wood boring pests.
UC3 is moderate protection against mould, fungus, and insects. It’s best used for timber decking and cladding that does not have direct contact with the ground and allows for quick water drainage.
UC4 timber has been significantly protected against mould, fungus, and insects, perfect for timber fence panels exposed to the elements. It is also useful for decking that has direct contact with the ground or with water.
Certification
The certification of the timber is the proof that it was derived from sustainably harvested lumber. In this age of deforestation and climate change, it’s never been so important to get your wood from sustainable sources. At Celtic Timber, all our wood is either certified from the FTC or the PEFC.
When you buy timber online and notice “available certified” in the specification, you’ll have to jump through a few extra hoops (and a bigger quote price) to get proper certified timber.