Common Wood Defects: Types & Causes of Lumber Issues
Unfortunately, there are very few perfect pieces of lumber out there. If you are going to build a deck, you might as well become familiar with the different types of defects so you know what to watch out for.
Defects in lumber are faults that detract from the appearance and utility of the wood. Some are present when the wood is produced and others develop or become more severe as the wood ages. As a general rule, you can reduce the amount of defects by purchasing higher-grade materials at the outset.
Properly drying the wood before it is installed will also help. Using protective stains on your deck can prevent some damage to the wood by slowing down the drying process in order to limit checking. Stains can also conceal visual defects by covering them with a consistent color throughout the deck.
Warping is any variation from a true plane surface on a piece of lumber. This occurs due to the differences between radial, tangential and longitude shrinkage in a piece of wood or growth stresses that encourage the board to reform its original shape.
Manufacturing Defects For Decking
These are defects found in lumber that are caused by sawing and dressing lumber. The machining process to produce dimensional lumber puts a large amount of stress on wood. In trying to reshape a large uneven log composed of complicated grain patterns into usable lumber can cause reactions that produce low-quality lumber.
Roller Check – Roller check occurs when a cupped board is mechanically flattened between roller planes. A light roller check is up to 2’ long, a medium roller check is between 2’ and 4’ long and heavy roller check is more than 4’ long.
Skip – Skip is referred to as any area where the planer missed the surface, leaving it roughed up. Skip is caused when the width or thickness of a piece is too small for the planer to remove all the rough surfaces.
Machine Burn – Machine burn is the visible darkening of wood due to the overheating of the knives, usually because they are too dull. This defect can usually be removed by sanding.