Lumber Buying Tips and Tricks
Lumber is essential in homebuilding and remodeling. Even a solid masonry house may have a large proportion of wood elements, including rafters and joists, and the studs in a stud wall. In addition to these, there are decorative aspects: doors, moldings, and stairways. These pages deal with the different types of lumber used in homes, the properties of different woods, and sourcing sustainable lumber.
Hardwood and Softwood
Hardwood is usually harvested from deciduous trees (ones that shed their leaves), and softwood from coniferous trees (which bear cones). Hardwoods take longer to grow, and are more resilient than softwoods, so they are considered to be higher-quality woods. Because of this, they are more expensive. This does not mean that softwood is a less effective building material — indeed, it makes up the bulk of all lumber used in the home. It is used planed on all four sides in structural components such as wall studs, and planed for moldings such as baseboards. Some of the more common hardwoods and softwoods used in house construction and decoration are detailed below.
Oak: A traditional building material, oak is common in many homes. "Green" (newly harvested) oak is still sometimes used to make timber frames for houses; when green, it is still soft, so is more easily cut and shaped. As it dries, oak acquires a hardness more like concrete than like wood, making it a very strong construction material. In addition to structural elements, oak can also be used for decorative elements to provide a high-quality finish.
Uses include: Structure of many houses, decorative beams, kitchens, veneer on kitchen units, flooring, decorative carpentry such as baseboard and architrave
Beech: A straight-grained hardwood with a fine, even texture. American beech is light or reddish brown in color, while European beech is a lighter, yellowish brown color.
Uses include: Kitchen counters, floors (veneer), decorative moldings such as quadrant, scotia, etc.
Teak: Teak is a dark hardwood, sometimes used in finish carpentry to provide a high-quality finish.
Uses include: Staircases, garden and indoor furniture
Idigbo: Resilient and easily worked, Idigbo is also very reasonably priced for a hardwood
Uses include: Woodworking
Mahogany: More commonly associated with furniture than with house construction
Uses include: Furniture, paneling in period properties
Maple: A highly decorative hardwood with a light, attractive appearance and hardwearing characteristics.
Uses include: Flooring, cabinets, stair parts, veneers
American black walnut: A coarse, dark hardwood used in some aspects of interior carpentry.
Uses include: Kitchens, veneers
Pine: One of the most commonly used woods. Some species of pine can contain more orange or red streaks.
Uses include: Rough carpentry, finish carpentry
Cedar of Lebanon: Another light-colored softwood. Often used in interior carpentry.
Uses include: Rough carpentry, finish carpentry
Western red cedar: Has a red-tinged appearance. Used mainly for exterior applications.
Uses include: Paneling, shingles, decking
Douglas fir: Has a definite reddish brown tinge, and is commonly used in plywood.
Uses include: Construction, decking, flooring
Hemlock: A light, nonresinous wood.
Uses include: Doors, windows, framing
Characteristics of Wood
In addition to choosing a type of lumber, think about other qualities it needs. These are not mutually exclusive; a piece of lumber can be both seasoned and treated, for example.
Wood has a high moisture content when it is first cut, and needs to dry out ("season") before being used. When you buy wood, it will often still have a relatively high moisture content. Wood can distort during the drying process. To overcome this, store it horizontally, above ground level, and supported evenly along its length. Before using lumber, leave it to acclimate for a few days in the environment where it will be used. Most suppliers produce kiln-dried lumber, on which seasoning has been accelerated and the wood artificially dried. Using kiln-dried wood can prevent problems later.
Lumber for finish carpentry such as baseboards does not need to be treated. Rough carpentry (e.g., rafters or a stud wall) needs treated wood. Pressure-treated wood is usually tanalized (impregnated with a preservative, shown here), and has a green or brown tint. It can be placed in contact with outside surfaces, such as soil, where there is a high risk of damp attack or insect infestation. All wood, however well treated, will break down eventually, but the degree to which it has been treated will influence its working life span.
Regardless of the type of wood, and whether it has been seasoned or treated, make sure you know whether your supplier is selling it by its rough-sawn or its planed size.
Rough-Sawn Wood vs. Planed Wood
Wood may be supplied either rough-sawn or planed (smoothed on all sides). This can make buying it confusing because lumber is usually priced and sold according to its dimensions when it is first cut into rough-sawn lengths. Rough-sawn lumber is therefore close to the size stated when you buy it, although it may be slightly smaller due to shrinkage during the drying process. But planed lumber is smaller than its labeled size, because it has been smoothed with a plane on all sides. When you go to your local lumberyard to purchase lumber, you'll need to know their actual sizes.
Used where it will not be visible — in a stud wall, for example. It will be close to the size quoted, because lumber is measured when it is rough-sawn.
Used where it will be visible, such as for a baseboard. It may not be the stated size, because wood has been removed from every face to give the smooth finish.
Green sources of lumber
The most important issue when buying new wood is to know whether it has come from a sustainable source. Lumber from recognized sources usually bears a stamp, such as that of the internationally recognized Forest Stewardship Council — a not-for-profit organization that promotes the responsible management of forests.
Reclaimed wood has the advantage of being thoroughly seasoned, and may look more appealing than new lumber. However, some of it may be unusable, so check for damage when buying.
Checklist When Buying Lumber
- Make sure that the wood you are buying comes from a sustainable resource.
- Find out how it has been treated and seasoned, and how it has been stored.
- Check lengths to see if they are bowed or warped, are split, are damp, or contain excessive or dead knots.
- Find out whether the quoted sizes are nominal or actual, so that you get the correct quantity of lumber.
- Ask if the supplier will deliver to your home. This can be useful if you require a large quantity and/or particularly long lengths. Check lumber carefully when it is delivered.
When buying wood, look out for splits, knots, and uneven grain. Splits can occur naturally in wood due to shrinkage or growth defects, but it is more likely that the wood has been dried too rapidly or the planks stored incorrectly. Softwoods damage and warp more easily when being stored. You will pay more for defect-free wood, but it is worth examining lumber thoroughly before purchasing.
Bent or twisted wood is difficult to saw accurately. Bending is usually caused by stacking or otherwise storing wood badly. Bowed or warped lumber may have unseen stresses due to the twisting. Look along the lumber for signs of bowing or warping.
In rough carpentry, knots, shown here, are hidden and don't matter. They may spoil finish carpentry by bleeding (especially on softwood) or showing through paint. Treat them with knotting solution first.
Copyright 2009 Dorling Kindersley Limited
Text copyright 2009 Julian Cassell and Peter Parham