What is softwood?
Softwood is an organic product that comes from the trunks, and sometimes the branches, of coniferous, or cone-bearing, trees.
Softwood, usually supplied in long, rectangular shapes such as planks, posts and rails, has some key roles in holding our modern world together.
About 80 percent of all timber comes from softwood, which is another way of saying it is about four times more common than hardwood.
Softwood is sometimes used as a substitute for hardwood, primarily because it's generally cheaper. But there are other reasons, including the fact that it's usually lighter and easier to cut and shape as it yields more readily to cutting tools and machines.
What is softwood used for?
Buildings, furniture and thousands of other things
It’s used in the construction of most houses – particularly in the roof and inner walls – and many other buildings, as well as furniture, containers and pallets, fences, doors and literally thousands of other things.
It’s also the main constituent of some man-made boards, such as medium density fibreboard, which have their own huge range of applications.
How is softwood formed?
Heartwood and sapwood
As the trunk and branches of a tree grow bigger, the insides of the cells they are composed of deteriorate and die, leaving behind just the cell walls, which become what is known as the heartwood.
The only living part of the trunk or branch is the part known as sapwood, between the heartwood and the bark – the tree’s protective covering. The sapwood continues to transport nutrient from the ground to the higher reaches of the tree.
The dead heartwood is what – after being sawn and planed – becomes the softwood that is used in thousands of different ways.
How is newly-felled softwood dried?
|After felling and usually (but not always) after being cut into large, initial shapes, softwood is either left to dry naturally over several months – even years in some cases – or quickly dried in a purpose-built oven, known as a kiln.|
What types of trees do softwoods come from?
Softwood comes from coniferous trees such as pines, larches, spruces, cypresses, and their relatives.
These are evergreen trees that have fine, needle-shaped leaves. They are generally faster-growing than hardwood trees and so softwood is thought of as being more “sustainable” – continuous fresh planting maintains a cycle of growth and felling covering about 30 years.
How soft is softwood?
Softwood isn't really soft at all – at least not in the way that a jelly or a cushion is soft – otherwise it could hardly be used in buildings, furniture, doors and other structures that need to be quite strong. Generally speaking, it is simply a bit softer than most hardwoods.
However, there are some softwoods that are harder than many hardwoods – for instance, yew is a hard softwood. Conversely, some hardwoods are softer than some softwoods. But generally speaking, hardwoods are hard and softwood is softer.
What sizes of softwood are available?
Softwood usually comes in standard lengths from 1.8m (5' 11") up to 6.3m (20' 8"), with other lengths at 300mm (11 13/16”) increments in between. Timber merchants in general won't stock smaller sizes, preferring to sell the longer lengths, although some merchants may cut pieces for you within reason.
Why 300mm increments?
The 300mm increment is used because the lengths are an approximation of the old imperial sizes in feet (1 foot is about 300mm).
Typical thicknesses are from 16mm (5/8”) to 100mm (4”), while widths go from 75mm (3”) to 275mm (11”). Note that not all combinations of thickness, width and length are available – if you're not sure of available sizes, get advice from timber merchants and/or DIY stores.
Why your softwood might be smaller than you think
Softwood is sold in various states of preparation. Rough-sawn stock is sawn but not planed; PSE (planed square edge) is planed on one edge only; PBS (planed both sides) is planed on two sides; and PAR (planed all round) is planed on two sides and two edges (but not the short, “end grain” edges).
Quoted sizes are usually for rough-sawn wood. The planed versions will be slightly smaller due to a little of the surface area being lost during planing.
Although yew, some types of pine, and redwoods are considered by many to be attractive, softwood generally lacks the more aesthetic qualities of hardwood.
Softwood generally tends to be light-coloured with less distinct grain, and it is often very knotty – the knots are the circles and ovals resulting from branches growing out laterally from the trunk. The heartwood eventually forms around these as the tree continues to grow, so part of the shape of the branch is trapped in the grain of the trunk wood.
Lighter weight and more easily damaged
Most softwoods are quite light compared with hardwoods. Because they are usually not as hard, they tend to split and break more easily, but they are easier to work on with cutting tools.
Strength in numbers
Although they may be relatively weak individually, lengths of softwood used together in a formation – such as a series of roof trusses – are collectively very strong.
Did you know?
Timber for building is graded according to British Standard (BS) EN 338:2003 Structural Timber, which gives 12 grades for softwoods, from C14 up to C50. The numbers represent the characteristic bending stress for each strength class. Builders merchants or wood yards usually supply timber stamped with the grade, so you can satisfy building inspectors that you meet regulations.
Summary of softwood's advantages and disadvantages